IMMUNO

Question 1

Which virus is most closely associated with Kaposi’s sarcoma in HIV-infected patients?
1 Human herpes virus 2
2 Cytomegalovirus
3 Human herpes virus 6
4 Human herpes virus 8
5 Epstein-Barr virus

Answer 1

Human herpes virus 8
HHV-8 has been repeatedly associated with all forms of Kaposi’s sarcoma.

Question 2

Which antibody is most commonly found in circulation of patients with atopic dermatitis?
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM

Answer 2

IgE
IgE is an anaphylactic antibody that is involved in nearly all immediate allergic and anaphylactic type reactions and commonly seen in elevated levels in patients with atopic dermatitis. Mast cells, basophils, langerhans cells, dermal dendritic cells as well as monocytes from atopic individuals all express high-affinity Fc�RI receptor which can bind IgE. More recently, it became clear that can bind monomeric IgE via the high-affinity Fc�RI IgG is the antibody that can cross the placenta and the most common antibody found in circulation. IgA is found in mucous membrane secretions and is able to agglutinate antigens and activate the alternate but not the classic complement pathway. IgD is not found in circulation other than in hyper-IgD syndrome, an autosomal recessive disorder caused by mutations in the mevalonate kinase gene. A significant elevation of serum IgD is seen in 95% of these patients. IgM is the antibody produced in the early stages of antibody responses. It is a pentamer which can agglutinate antigen and active the classic complement pathway.

Question 3

Tacrolimus is a non-steroidal anti-inflammatory medication that works by inhibiting calcineurin activity through complexing with what binding protein?
1 FK506
2 TGF-beta
3 NF-kappa-B
4 SRE
5 IL-23

Answer 3

FK506
Tacrolimus and pimecrolimus are non-steroidal calcineurin inhibitors that act as anti-inflammatory medications. In dermatology, they are most commonly used in topical preparations. These medications form complexes with FK506 binding protein, which inhibits calcineurin activity. A key regulatory step in the activation of T cells is the activation of calcineurin via calmodulin.

Question 4

All of the following stains can be reactive in this condition except
1 CDXIIIa
2 CD31
3 CD34
4 Ulex europaeus
5 Factor VIII-related antigen

Answer 4

CDXIIIa
The picture shows Kaposi’s scarcoma(KS). It is controversial whether KS represents neoplasia or hyperplasia; all clinical variants are viewed as a virally induced disease - human herpesvirus 8 (HHV-8) is the suspected agent. Cutaneous lesions present as variably distributed pink patches, blue-violet to black nodules or plaques, and polyps, depending on clinical variant and stage. Variable staining can occur with CD31, CD34, Ulex europaeus and factor VIII-related antigen. CD XIIIa is positive in dermatofibroma.

Question 5

Which systemic anti-inflammatory agent specifically blocks the ability of T cells to leave the vasculature and enter the skin?
1 Etanercept
2 Infliximab
3 Efalizumab
4 Alefacept
5 None of the above

Answer 5

Efalizumab
Efalizumab is a humanized monoclonal antibody to CD11a that blocks the immunologic synapse between LFA-1 on the T-cell and ICAM-1 on the antigen presenting cell. By targeting LFA-1 efalizumab specifically blocks the ability of T cells to leave the vasculature and enter the skin.

Question 6

Angiocentric NK/T-cell lymphoma in children may present as:
1 Papular acrodermatitis of childhood
2 Acropustulosis of infancy
3 Childhood dermatomyositis
4 Hydroa vacciniforme
5 En coup de sabre

Answer 6

Hydroa vacciniforme
Hydroa vacciniforme a photodermatitis that typically occurs with sun exposure in the spring has been reported with NK/T cell lymphomas in childhood.

A vesicular and bullous eruption having a tendency to recur in summer during childhood and commonly appearing on sun-exposed skin. The lesions are surrounded by an erythematous zone and resemble a vaccination

Question 7

Which of the following TH2 cytokines is a B cell growth factor?
1 IL-4
2 IL-5
3 IL-10
4 IL-13
5 IFN-gamma

Answer 7

IL-4
IL-4 is a B cell growth factor. IL-5 is an eosinophil growth factor. IL-10 is a general down-regulator of TH1 immunity. IL-13 (along with IL-4) promotes an isotype switch from IgM to IgE. IFN-gamma is not a TH2 cytokine. It is secreted by TH1 cells, and is the main macrophage-activating cytokine.

Question 8

Dermatitis herpetiformis is associated with which HLA type(s)?
1 HLA-B8
2 HLA-DR3
3 HLA-DQw2
4 All of the above
5 None of the above

Answer 8

Dermatitis herpetiformis is associated with

HLA-B8, -DR3, and -DQw2.

Question 9

All of the following statements regarding Langerhans cells are true EXCEPT:
1 They are highly phagocytic
2 They express CD1 on their surface
3 They are found in some areas of lymph nodes and spleen
4 They have a high density of Class II molecules on their surface
5 None of these answers are correct

Answer 9

They are highly phagocytic
Langerhans cells are dendritic cells found in high concentrations in epithelial surfaces and some areas of lymph nodes and spleen. They express CD1 on their surface and have a high density of Class II MHC molecules. They are poorly phagocytic.

Question 10

Which of the following dietary supplements may inhibit platelet function?
1 Vitamin A
2 Vitamin C
3 Vitamin D
4 Vitamin E
5 Vitamin K

Answer 10

Vitamin E
Supplemental vitamin E can inhibit platelet function and predispose to hemorrhagic stroke. It can be particularly hazardous in patients with beta-thalassaemia mutations.

Schematic model showing the beneficial role of α-tocopherol on the extracellular matrix (ECM). α-Tocopherol can induce connective tissue growth factor (CTGF) (Villacorta et al., 2003) and subsequently collagen, and it inhibits collagenase (MMP-1) expression (Ricciarelli et al., 1999), due to specific inhibition of protein kinase C (PKC) activity (Ricciarelli et al., 1998); these events may lead to acceleration of wound repair processes as well as to stabilization of the fibrous cap.

Question 11

IL-23 plays a critical role in the pathogenesis of psoriasis. Which of the following cytokines is critical for IL-23-mediated epidermal hyperplasia in psoriasis?
1 IL-2
2 IL-12
3 IL-17A
4 TNF-alpha
5 IFN-gamma

Answer 11

IL-17A
IL-23 and Th17 cells producing IL-17A and IL-22 are found in excess in skin affected by psoriasis. IL-6, IL-22, and IL-17A have all been shown to be critical in mediating epidermal hyperplasia in psoriasis in response to IL-23.

Question 12

Which of the following diseases occur with an increased frequency in persons deficient in C2?
1 Psoriasis
2 Dermatitis Herpetiformis
3 Androgenetic Alopecia
4 DLE
5 Leiner’s disease

Answer 12

DLE
Among the complement deficiencies, C2 defienciency is most frequently seen. Most of these patients are healthy. Diseases that occur with increased frequency in patients with C2 deficiency are SLE, SLE-like syndrome, frequent infections, anaphylactoid purpura, lethal dermatomyositis, vasculitis, disseminated cutaneous lupus erythematosus, and cold urticaria.

Question 13

Immunocytomas are:
1 Low grade B-cell lymphomas
2 Aggressive B-cell lymphomas
3 Low grade T-cell lymphomas
4 Aggressive T-cell lymphomas
5 NK cell lymphomas

Answer 13

Low grade B-cell lymphomas
These indolent tumors present as solitary or multiple nodules usually on the extremities. The cells have been reported to have CD-20 (B cell marker) and have been reported to be bcl-2 positive.

Question 14

Which cytokine is not upregulated in atopic dermatitis patients?
1 IL-13
2 IL-4
3 IL-5
4 IL-10
5 IFN-gamma

Answer 14

IFN-gamma
Interferon gamma is Th1 cytokine which downregulates Th2 responses. The remaining are Th2 cytokines active in atopic dermatitis. IL-4 is a B-cell growth factor and active in signaling isotope switching from IgM to IgE. IL-5 is an eosinophil growth factor. IL-10 downregulates Th1 immunity and IL-13 signals isotope switching along with IL-4.

Question 15

Which of the following immune-mediated events has been demonstrated in psoriasis vulgaris?
1 Clonal expansion of CD8+ T cells
2 Decrease dermal Langerhans cells
3 Downregulation of keratin 16
4 Increase Th2 CD4+ T cells
5 Decreased production of interferon-gamma

Answer 15

Clonal expansion of CD8+ T cells
The involvement of T cells in the pathophysiology of psoriasis vulgaris is well-recognized. Availability of monoclonal antibodies has allowed for extensive characterization of T cell subsets and other mediators increased in psoriasis lesions. CD8+ T cells are highly concentrated in psoriatic epidermis and studies have demonstrated increased IL-2R and HLA-DR surface molecules indicative of persistent activation. Clonal expansion of CD8+ T cells has been observed suggesting that this subset is the major antigen-reactive population.

Question 16

Which cytokine is primarily responsible for stimulation of neutrophils?
1 IL-1
2 IL-4
3 IL-5
4 IL-6
5 IL-8

Answer 16

IL-8
IL-8 is primarily responsible for the stimulation of neutrophils. IL-5 stimulates eosinophils. IL-4 stimulates mast cells and IgE isotype switching.

Question 17

The elicitation of nickel contact dermatitis requires signaling by which of the following?
1 TLR2
2 TLR4
3 LFA-1
4 TNF-alpha
5 IL-4

Answer 17

TLR4
Allergies to nickel (Ni(2+)) are the most frequent cause of contact hypersensitivity (CHS) in industrialized countries. The efficient development of CHS requires both a T lymphocyte-specific signal and a proinflammatory signal. Ni(2+) triggers an inflammatory response by directly activating human Toll-like receptor 4 (TLR4). Studies with mutant TLR4 proteins revealed that the non-conserved histidines 456 and 458 of human TLR4 are required for activation by Ni(2+) but not by the natural ligand lipopolysaccharide.

Question 18

In adult patients with Henoch-Sch�in purpura with IgA vasculitis, which of the following complications is most likely to occur?
1 Pulmonary hemorrhage
2 Hemorrhagic cystitis
3 Peripheral neuropathy
4 Mesangial nephropathy
5 Facial edema

Answer 18

Mesangial nephropathy
A urinalysis should be ordered in patients with palpable purpura. Red blood cells and proteinuria are often seen in Henoch-Sch�in syndrome.

Question 19

Serum IgA antibodies to tissue transglutaminase occur in:
1 Bullous pemphigoid
2 Linear IgA disease
3 Pemphigus foliaceus
4 Bullous lupus erythematosus
5 Dermatitis herpetiformis

Answer 19

Dermatitis herpetiformis
Autoantibodies to tissue transglutaminase are an area of active investigation in both celiac disease and dermatitis herpetiformis.

Question 20

All the following conditions exhibit a T-helper cell 1 (Th1) cytokine secretion profile except:
1 Psoriasis
2 Systemic lupus erythematosus
3 Granulomatous leprosy
4 Rheumatoid arthritis
5 Multiple sclerosis

Answer 20

Systemic lupus erythematosus
Systemic lupus erythematous is associated with a Th2 cytokine profile, whereas the other conditions are associated with a Th1 cytokine profile. Th2 cells are typified by secretion of IL-4, IL-5, IL-6, IL-9, IL-10 and IL-13, whereas Th1 cells are typified by secretion of IFN-gamma, TNF-beta, and IL-2.

Question 21

Which of the following immunoglobulins cannot activate the complement pathway?
1 IgM
2 IgG1
3 IgG2
4 IgG3
5 IgG4

Answer 21

IgG4
 Immunoglobulins (Ig) differ in their ability to activate complement. IgM is the largest Ig, is the major Ig in the primary immune response, and consists of a pentamer that activates the classic complement pathway. IgG is the most abundant Ig and the major Ig in the secondary immune response. Four subclasses of IgG exist based on the amino acid residue sequences of their constant region, IgG1 through IgG4. IgG1 and IgG3 are potent activators of the classic complement pathway, IgG2 is less effective and IgG4 is unable to do so.

Question 22

Which cytokine is chemotactic for neutrophils?
1 IL-2
2 IL-3
3 IL-5
4 IL-6
5 IL-8

Answer 22

IL-8
IL-8 is chemotactic for neutrophils. The other cytokines elicit other types of immune cells, IL-2 (T-ells), IL-3 (mast cells), IL-5 (eosinophils), IL-6 (plasma cells).

Question 23

Each cytokine activates what type of cell?

Plasma cells

Mast cells

Eosinophils

Neutrophils

T-cells

Answer 23

IL-8
IL-8 is chemotactic for neutrophils. The other cytokines elicit other types of immune cells, IL-2 (T-ells)

IL-6 (plasma cells)

IL-3 (mast cells)

IL-8 (neutrophils)

IL-5 (eosinophils)

IL-2 (T-cells)

Question 24

Calcipotriene-induced improvement in psoriasis is associated with increased lesional levels of which cytokine?
1 Interleukin-2
2 Interleukin-8
3 Tumor necrosis factor
4 Interleukin-10
5 Interluekin-12

Answer 24

Interleukin-10
Psoriasis is generally described as a TH1 autoimmune disease where IL-12/IFN-gamma pathway is dominant. IL-10 is the prototype of TH2 and calcipotriene application results in increased levels of IL-10, thus decreasing TH1 disease.

Question 25

An 8 month-old baby with diffuse purpura is admitted to the hospital for her third episode of bacterial meningitis. Which component of her immune system is impaired?
1 CD4 + T cells
2 Natural killer cell activation
3 CD8 + T cells
4 Complement activation
5 Antibody production

Answer 25

Complement activation
Predisposition to sporadic and occasionally recurrent meningococcal disease occurs in patients with congenital or acquired complement deficiencies, particularly late acting components C5-9

Question 26

Gene rearrangement analysis is usedful for determining:
1 Lymphocyte clonality in mycosis fungoides
2 Lymphocyte activity
3 Gene Function
4 Gene Mutations
5 T cell receptor status

Answer 26

1 Lymphocyte clonality in mycosis fungoides
Gene rearrangement studies are useful to detect clonality in antigen specific cell types (B cells, T cells).

Question 27

Imiquimod induces which of the following cytokines?
1 Interleukin-10
2 Interferon-alpha
3 Interleukin-2
4 Interleukin-4
5 Interleukin-5

Answer 27

Interferon-alpha
Imiquimod is a topical immunomodulator that increases a variety of cytokines including interferon-alpha.

Question 28

When attempting to identify Langerhans cells in a specimen, which marker is most helpful?
1 CD1
2 CD4
3 CD7
4 CD8
5 CD20

Answer 28

CD1
CD1 is a surface antigen specific for epidermal Langerhans cells. It is not expressed in other epidermal structures. The other characteristic ultrastructural feature of Langerhans cells is the Birbeck granule. CD4 is found on T-helper cells and occasionally on Langerhans cells. CD7 is a T-cell marker that is often lost in cutaneous T-cell lymphoma. CD8 is found on cytotoxic T-cells. CD20 is a B-cell marker.

Question 29

The most definitive HLA association with psoriasis is:
1 HLA-Cw6
2 HLA-B27
3 HLA-B13
4 HLA-B17
5 HLA-B37

Answer 29

HLA-Cw6
HLA-Cw6 is associated with a 9-15x greater risk for developing psoriasis. All of the other HLA antigens listed are associated with various types of psoriasis, but at with lesser strength of association.

Question 30

Patients with a type I reaction to latex may have cross-reactions with which of the following foods?
1 Avocado
2 Horseradish
3 Cashews
4 Parsnips
5 Garlic

Answer 30

Avocado
Latex allergy is a TH2 form of contact sensitivity that is IGE mediated. Using the old Gel and Coombs classification, it was classified as type I hypersensitivity.

Question 31

Which of the following cytokines is primarily involved in activating eosinophils?
1 IL-5
2 TNF-alpha
3 IL-10
4 IL-2
5 Interferon-gamma

Answer 31

IL-5
5 Interferon-gamma
Eosinophils provide many functions of the immune system, including protection against helminths. They are activated by IL-5

Question 32

Which cytokine is upregulated in lesions of tuberculoid leprosy?
1 IL 2
2 IL 4
3 IL 5
4 IL 10
5 None of the answers are correct

Answer 32

IL 2
Tuberculoid leprosy is characterized by a type I immune related response. Tuberculoid leprosy has increased amounts of TH1 cytokines including IL-2, interferon gamma, and IL-12. These lead to a t-cell and macrophage mediated cytotoxic response. IL-4, IL-5, and Il-10 are typically downregulated in tuberculoid leprosy.

Question 33

Toll-like receptors (TLRs) have been found to play an important role in innate immunity. This has been utilized in the development of medications frequently used in dermatology. The mechanism of what medication involves activation of TLR7.
1 Clobetasol
2 Tacrolimus
3 Cyclosporine
4 5-Fluorouracil (5-FU)
5 Imiquimod

Answer 33

Imiquimod
TLRs recognize pathogen-associated molecular patterns (PAMPs) present in a variety of pathogens and activate signaling pathways involved in innate immunity, as well as augmenting adaptive immunity. The mechanism of action of imiquimod involves activation of these pathways via TLR7. None of the other medications listed above involve TLRs as their main mechanism of action.

Question 34

T-cell anergy occurs if:
1 Stimulation by a MHC Class III molecule is involved
2 MHC/TCR engagement occurs without costimulatory molecules
3 FasL is bound on the T-cell
4 MHC Class I or II is bound in the presence of IL-2
5 A HLA-DM facilitator is not involved with the binding

Answer 34

MHC/TCR engagement occurs without costimulatory molecules
 MHC/TCR engagement occurs without costimulatory molecules. MHC Class III molecules are not involved in this process. The MHC III region encodes for soluble proteins of the complement cascade and the tumor necrosis family. Fas-FasL interactions promote apoptosis on the target cell, not stimulation. IL-2 is a stimulatory molecule, produced by Th1 T-cells. It does not produce anergy. HLA-DM facilitates loading of proteins processed by antigen presenting cells into the MHC class II molecule before being brought to the cell surface.

Question 35

A deficiency of this complement component may result clinically in susceptibility to pyogenic infections, glomerulonephritis, and partial lipodystrophy:
1 C1 Esterase Inhibitor
2 C3
3 C4
4 C50
5 Properidin

Answer 35

2 C3
C3 is the central component of the complement cascade. It plays a key role in the opsonization of bacteria. An autosomal recessive deficiency of C3 may result in susceptibility to pyogenic infections, glomerulonephritis, and partial lipodystrophy.
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Question 36

Anti-epiligrin (laminin 5) antibodies may be seen in:
1 Pemphigoid gestationis
2 Pemphigus vegetans
3 Fogo selvagem
4 Cicatricial pemphigoid
5 Paraneoplastic pemphigus

Answer 36

4 Cicatricial pemphigoid
Patients with cicatricial pemphigoid have been reported to have anti-epiligrin antibodies.

Question 37

Psoriasis affects over 2% of the world�s population and has a strong association with which HLA class I haplotype?
1 HLA-DR4
2 HLA-DR1
3 HLA-CW6
4 HLA-B27
5 HLA-DQ6

Answer 37

3 HLA-CW6
HLA-CW6 has been seen in up to 90% of patients with early onset psoriasis, 50% with late onset psoriasis and only 7.4% of the general population. HLA-DR1 and DR4 are both related to Rheumatoid Arthritis and have a 7x increased relative risk (RR) for developing disease. HLA-B27 is linked to ankylosing spondylitis, postinfection arthridites and Reiter�s disease, with increase relative risks of 100x, 10-20x, and 35x respectively.
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Question 38

All of the following statements regarding Natural Killer (NK) cells are true EXCEPT:
1 NK cells have properties of innate and acquired immunity
2 NK cells express CD 2 molecules
3 NK cells are large granular lymphocytes
4 NK cells mediate tumor lysis
5 NK cells mediate lysis of viral-infected cells

Answer 38

2 NK cells express CD 2 molecules
NK cells do not express CD 2 molecules. The other statements are true.

Question 39

The putative mechanism of action of topical macrolide immunomodulators is inhibition of:
1 Lymphokine production
2 Prostaglandin secretion
3 Antigen presentation
4 Neutrophil migration
5 Lymphocyte migration

Answer 39

Lymphokine production

Tacrolimus and pimecrolimus are topical macrolide immunomodulators that inhibit lymphokine or cytokine production via binding to macrophilin. This complex inhibits calcineurin, a phosphatase involved in the activation of NF-AT. This suppresses the production of IL-2 and IFN-gamma (TH1 cytokines) as well as IL-4, 5 and 13 (TH2 cytokines). In addition, they decrease the expression of IgE receptors on Langerhans cells and reduce mast cell degranulation.
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Question 40

Anti Jo-1 antibodies are directed against which of the following?
1 Topoisomerase
2 Lysyl oxidase
3 Gyrase
4 Histidyl transfer RNA synthetase
5 Telomerase

Answer 40

Histidyl transfer RNA synthetase

Anti Jo-1 antibody is typical of autoimmune diseases that involve muscle, including dermatomyositis.

Question 41

Rituximab works by targeting the CD20 antigen which is predominantly expressed on which of the following cells?
1 Plasma cells
2 B cells
3 B cells and plasma cells
4 T cells
5 Dendritic cells

Answer 41

B cells
Rituximab targets the CD20 antigen which is predominantly expressed on mature B cells but not plasma cells, T cells, or dendritic cells. Therefore, even when used in antibody-mediated diseases (such as pemphigus vulgaris), the response to therapy requires a long duration of time as the drug targets B cells which must then differentiate into plasma cells that ultimately produce the pathogenic antibodies in their secreted form.

Question 42

Psoriatic arthritis is most commonly associated with which HLA?
1 HLA-B27
2 HLA-Cw6
3 HLA-Aw19
4 HLA-Bw35
5 None of these options are correct

Answer 42

HLA-B27 is associated with an increase in psoriatic arthritis as well as pustular psoriasis and acrodermatitis continua of Hallopeau.

Question 43

Herpes gestationis is most commonly associated with which HLA?
1 HLA-DR3
2 HLA-B27
3 HLA-B51
4 HLA-DR9
5 HLA-DQ8

Answer 43

HLA-DR3 is the most commonly found HLA association in herpes gestationis. HLA-DR4 is also found in addition to HLA-DR3 in about 50% of patients. There is nearly 100% incidence of anti-HLA antibodies patients affected by herpes gestationis.

Question 44

A male infant presents with thrombocytopenia, eczema, and recurrent infections. You suspect which of the following immunodeficiency disorders?
1 Ataxia telangiectasia
2 Di-George anomaly
3 Hyper-IgM syndrome
4 Leiner’s disease
5 Wiskott-Aldrich syndrome

Answer 44

Wiskott-Aldrich syndrome is an X-linked recessive disorder that presents with thrombocytopenia, small defective platelets, eczema, autoimmune disease, infections, and lymphoreticular malignancy.

Question 45

A 44 year old female complains of intra-oral burning lesions. Examination reveals erythematous plaques with white striae on the buccal mucosa consistent with oral lichen planus. No cutaneous lesions are seen. Which of the following HLA types is associated with oral lichen planus?
1 B8
2 Cw6
3 Bw35
4 B27
5 B51

Answer 45

Oral lichen planus is a relatively common condition that can cause significant morbidity. Oral lichen planus is associated with HLA-B8. HLA-Cw6 is associated with psoriasis, Bw35 with cutaneous lichen planus, B27 with psoriatic arthritis, and B51 with Behcet's disease.

Question 46

Which of the following is a criterion for the diagnosis of Behcet’sdisease?
1 Inflammatory bowel disease
2 Uveitis
3 Conjunctivitis
4 Nasal septal perforation
5 Lobular panniculitis

Answer 46

Behcet’s is a triad that includes oral ulcerations, genital ulcerations and uveitis. Behcet’s also displays arthritis and gastrointestinal disease. Blindness is the most-feared outcome, and relates to the uveitis.

Question 47

Which cytokine is responsible for fever in patients with sunburn?
1 IL-1
2 IL-5
3 IL-10
4 IL-11
5 TNF-beta

Answer 47

IL-1
IL-1 is a pyrogenic cytokine responsible for the fever in sunburn. It also is causes B cell maturation and proliferation and NK cell activation.

Question 48

Which cytokine is responsible for activating natural killer cells?
1 Interleukin 4
2 Interleukin 2
3 Interferon-alpha
4 Terferon-gamma
5 Tumor necrosis factor-alpha

Answer 48

Activation of natural killer cells occurs via interleukin 2 (IL-2). IL-2 is a key component of the Th1 (cell-mediated) immunity. It acts to promote growth, proliferation and activation of T cells, B cells and natural killer cells.

Question 50

Subacute cutaneous lupus erythematosus has been associated with the ingestion of which of the following drugs?
1 Phenytoin
2 Allopurinol
3 Terbinafine
4 Trimethoprim/sulfamethoxazole
5 Auranofin

Answer 50

SCLE has been reported to be associated with terbinafine. This condition is often associated with anti-Ro (SS-A) and anti-La (SS-B) antibodies.

Question 51

All of the following statements regarding Toll receptors are true EXCEPT:
1 Toll receptors are present on macrophages and dendritic cells
2 Toll 2 receptors are typically activated by lipopolysaccharide
3 Toll 4 receptors are typically activated by gram negative bacteria
4 Nuclear factor kappa B (NFKB) is the final common pathway of toll receptors
5 None of the above (all are true)

Answer 51

Bacteria can induce inflammation through activation of Toll receptors, which are present on a variety of cutaneous cells including macrophages, dendritic cells, keratinocytes, and mast cells. Typically, Toll 2 receptors are activated by gram positive bacteria and Toll 4 receptors are activated by lipopolysaccharide or gram negative bacteria. Nuclear factor kappa B is a final common pathway of toll receptors and other immune receptors involved in initiating a variety of proinflammatory cytokines.

Question 52

What cytokine is most critical for the development and maturation of eosinophils.
1 Interleukin-2
2 Interleukin-4
3 Interleukin-5
4 Interferon-alpha
5 Interferon-gamma

Question 53

This patient says the rash is spreading and not controlled with topical therapy. You give him a course of oral treatment that lasts:
1 1 week
2 2 weeks
3 3 weeks
4 4 weeks
5 5 weeks

Answer 53

Generally, for poison ivy dermatitis, if patients are given a course of oral steroids, the course should be at least 3 weeks long, as if the duration is shorter, patients may develop a rapid rebound.

Question 54

All of the following statements regarding major histocompatibility complex molecules are true EXCEPT:
1 MHC class II molecules bind stably to peptides derived from proteins sythesized and degraded in the cytosol
2 MHC class I molecules bearing viral peptides are recognized by cytotoxic T-cells that subsequently kill the infected cell
3 Class I molecules such as HLA-A, B, and C, are present on all nucleated cells
4 The MHC is located on chromosome 6 in humans
5 MHC Class II molecules bearing peptides are recognized by TH1 or TH2 cells.

Answer 54

MHC class I molecules bind stably to peptides derived from proteins sythesized and degraded in the cytosol, while MHC class II molecules bind stably to peptides derived from proteins degraded in endocytic vesicles. MHC class I molecules bearing viral peptides are recognized by cytotoxic T-cells that subsequently kill the infected cell. MHC Class II molecules bearing peptides trigger helper T-cells and are recognized by TH1 or TH2 cells. Class I molecules such as HLA-A, B, and C, are present on all nucleated cells, whereas Class II molecules are on B cells, monocytes, dendritic cells, and are inducible on keratinocytes and endothelial cells. The MHC is located on chromosome 6 in humans, its polygenic and polymorphic nature contributes to the ability of the immune system to respond to a multitude of different and rapidly evolving pathogens.
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Question 55

Which of the following suture materials induces the least inflammation?
1 Surgical gut
2 Polyglycolic acid (Dexon)
3 Polyglycan 910 (Vicryl)
4 Polypropylene (Prolene)
5 Silk

Answer 55

Prolene is a nonabsorbable suture material that evokes only minimal inflammation.

Question 56

Which T-cell subset is commonly found in S�zary syndrome?
1 CD4+/CD7+
2 CD8+/CD7-
3 CD4-/CD7+
4 CD4+/CD7-
5 CD8+/CD7+

Answer 56

Sezary syndrome is the leukemia phase of mycosis fungoides (cutaneous T-cell lymphoma) and is usually a TH2-biased CD4+ leukemia.

Question 57

Naive T cells express which of the following surface molecules:
1 CD19
2 CD20
3 CD79
4 CD45RO
5 CD45RA

Answer 57

Naive T cells express CD45RA whereas memory T cells express CD45RO. CD19, 20, and 79 are B cell surface markers.

Question 58

Which of the following B cell receptors is involved in immunoglobulin isotype switching?
1 CD40
2 CD19
3 CD20
4 CD154
5 CD22

Answer 58

CD40 activation on B cells by CD40-ligand (CD154) on T cells induces isotype switching from an IgM to IgG response. Defects in the expression of CD40-ligand result in an immunodeficiency state (hyper-IgM syndrome) characterized by low levels of IgG, IgA and IgE, but elevated IgM. CD19, CD20, CD22 are pan-B cell markers.

Question 59

Which cytokine is up-regulated in this geometric, eczematous dermatitis?
1 IL-2
2 IL-4
3 IL-5
4 IL-7
5 IL-10

Answer 59

The geometric pattern of ertyhema suggests “outside job”. Allergic contact dermatitis is a cell-mediated and Th1 reaction. The cytokines up-regulated in this process are IL-1, IL-2, IL-12, interferons-alpha and gamma.

Question 60

Anti-centromeric antibodies are associated with which rheumatologic disease?
1 CREST
2 Mixed connective tissue disease
3 SLE
4 Dermatomyositis/polymyositis
5 Progressive systemic sclerosis

Answer 60

Anti-centromeric antibodies are associated with CREST syndrome. Anti-RNP antibodies are associated with MCTD, anti-dsDNA, ssDNA, and Sm associated with SLE, anti-Jo-1 associated with polymositis, and anti-Scl 70 associated with PSS.

Question 61

This woman should have a workup for:
1 Lymphoma
2 Nephrolithiasis
3 Pancreatic cancer
4 Hemochromatosis
5 Thalassemia

Answer 61

Porphyria cutanea tarda has been shown to be associated with hemochromatosis. Patients with porphyria cutanea tarda have mutations in the HFE gene, and early detection of mutations can improve life expectancy for these patients.

Question 62

Which of the following is the target antigen in pemphigus vulgaris?
1 Desmoglein 3
2 Desmoplakin
3 Cadherin
4 Type XVII collagen
5 Desmoglein 1

Answer 62

Desmoglein 3 is the dominant target auto-antigen in pemphigus vulgaris.

Question 63

Keratinocytes express what class of major histocompatibility complex under normal conditions?
1 MHC Class I
2 MHC Class II
3 MHC Class III
4 MHC Class IV
5 MHC Class V

Answer 63

Keratinocytes express MHC Class I molecules and therefore can be attacked by CD8+ Tc cells, in particular after viral infection. Although keratinocytes do not express MHC Class II molecules under normal conditions, they can be induced to do so in the setting of inflammatory conditions.

Question 64

All of the following statements regarding neutrophils are true EXCEPT:
1 Neutrophils’ major function is antigen presentation
2 Neutrophils have receptors for IgG and complement
3 Neutrophils are granulocytes
4 Neutrophils are the most abundant leukocytes
5 None of these answers are correct

Answer 64

Neutrophils’ major function is phagocytosis. The other statements are correct.

Question 65

Which of the following immunoglobulin crosses the placenta?
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM

Answer 65

IgG is the antibody that can cross the placenta and the most common antibody found in circulation. IgA is found in mucous membrane secretions and is able to agglutinate antigens and activate the alternate but not the classic complement pathway. IgD is not found in circulation other than in hyper-IgD syndrome, an autosomal recessive disorder caused by mutations in the mevalonate kinase gene. A significant elevation of serum IgD is seen in 95% of these patients. IgE is an anaphylactic antibody that is involved in nearly all immediate allergic and anaphylactic type reactions. IgM is the antibody produced in the early stages of antibody responses. It is a pentamer which can agglutinate antigen and active the classic complement pathway.

Question 66

Which of the following HLA alleles is most strongly associated with Behcet�s disease?
1 HLA-B27
2 HLA-B51
3 HLA-DQw2
4 HLA-DR1
5 HLA-DR4

Answer 66

HLA-B51 has been reported with increased relative risks in European, Asian and Middle Eastern populations.

Question 67

Of the following complement components, the most powerful neutrophil chemoattractant is:
1 C3
2 C5a
3 C3a
4 C5b, C6, C7, C8, C9
5 C4a

Answer 67

The complement system plays an important role in innate immunity. Of this group, C5a is the most powerful neutrophil chemoattractant. C3 represents the endpoint for the classic, alternative and lectin pathways, and results in the generation of immunologically active substances. C3a and C4a cause mast cell degranulation. Assembly of C5b, C6, C7, C8, C9 components results in the membrane attack complex (MAC), which perforates cell membranes causing death by osmotic lysis.

Question 68

Of the following complement components, the most powerful neutrophil chemoattractant is:
1 C3
2 C5a
3 C3a
4 C5b, C6, C7, C8, C9
5 C4a

Answer 68

The complement system plays an important role in innate immunity. Of this group, C5a is the most powerful neutrophil chemoattractant. C3 represents the endpoint for the classic, alternative and lectin pathways, and results in the generation of immunologically active substances. C3a and C4a cause mast cell degranulation. Assembly of C5b, C6, C7, C8, C9 components results in the membrane attack complex (MAC), which perforates cell membranes causing death by osmotic lysis.

Question 69

Which systemic anti-inflammatory agent targets CD2+ activated T cells for apoptosis?
1 Etanercept
2 Infliximab
3 Efalizumab
4 Alefacept
5 None of the above

Answer 69

Alefacept is a soluble form of LFA-3 that blocks the immunologic synapse between CD2 on the T cell and LFA-3 on the antigen presenting cell. Furthermore, alefacept targets CD2+ activated T cells for apoptosis.

Question 70

The pharmacologic activity of tacrolimus includes:
1 Phosphorylation of NFAT (nuclear factor of transcription)
2 Binding and inhibition of NF kappa B
3 Inhibition of interleukin-1 gene transcription
4 Activation of calcineurin
5 Inhibition of interleukin-2 gene transcription

Answer 70

Tacrolimus is a macrolide similar to cyclosporine and pimecrolimus (Elidel). Calcineurin is a phosphatase that dephosphorylates subunit on NFAT (nuclear factor of activated T cells).

Question 71

A 27 year old gentleman with a known history of chronic plaque psoriasis complains of pain and stiffness of his joints, particularly in his hands. Which HLA subtype is associated with psoriatic arthritis?
1 B27
2 Cw6
3 B17
4 B51
5 B8

Answer 71

Psoriatic arthritis, as well as generalized psoriasis,is associated with HLA-B27. HLA-Cw6 is associated with psoriasis, Bw35 with cutaneous lichen planus, B8 with oral lichen planus, and B51 with Behcet’s disease.
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Question 72

Which of the following substances is located in the core of an eosinophil?
1 Eosinophilic cationic protein
2 Eosinophil-derived neurotoxin
3 Eosinophil peroxidase
4 Major basic protein
5 Chymase

Answer 72

Major basic protein is the only protein located in the core of an eosinophil. Eosinophil cationic protein, eosinophil-derived neurotoxin, and eosinophil peroxidase are all located in the matrix. Chymase is a mediator stored in granules of a mast cell.

Question 73

A very common pentadecacatechol sensitizer is found in all of the following plants/plant components except:
1 Gingko fruit pulp
2 Poison sumac
3 Mango fruit pulp
4 Cashew oil
5 Indian marking nut oleoresin

Answer 73

Mango fruit pulp

The sensitizer in rhus dermatitis is a pentadecacatechol found in the oleoresin of anacardaciae plants, including poison ivy/oak/sumac, mango rinds (but NOT pulp), cashew nutshells and oil, Indian marking nut oleoresin, gingko fruit pulp, and Japanese lacquer tree oleoresin.

Question 74

This patient has a lichenified plaque in the lower mid abdomen as well as these two exczematous plaques. This patient needs:
1 Patch testing
2 A steroid
3 An antiviral
4 A KOH scraping
5 An antifungal

Answer 74

This patient is likely allergic to the nickel in her belt buckle and possibly to metals that she places in her pocket. She needs patch testing. While a topical steroid might help resolve pruritus, the patient ultimately needs to be diagnosed with her allergy and avoid nickel. Dimethylglyoxime can be used as an indicator to detect nickel in metals.

Question 75

Which component of the T cell receptor is associated with superantigen recognition?
1 D-beta
2 J-alpha
3 J-beta
4 V-alpha
5 V-beta

Answer 75

V-beta

Superantigens are able to bypass many elements of the normal immune response. They are not processed by antigen presenting cells. Instead, they bind directly to the MHCII complex and interact with T cells in a relatively non-specific fashion. Whereas conventional antigens** require recognition in **all 5 elements** of the T-cell receptor (V-alpha, J-alpha, V-beta, D-beta, J-beta), **superantigens** are recognized by **V-beta alone.

Question 76

Which of the following cytokines, together with IL-4, promotes isotype switching from IgM to IgE?
1 IL-5
2 IL-10
3 IL-13
4 TNF
5 IFN-gamma

Answer 76

IL-5 is an eosinophil growth factor. IL-10 is a general down-regulator of TH1 immunity. IL-13 (along with IL-4) promotes an isotype switch from IgM to IgE. TNF and IFN-gamma are TH1 cytokines, TH2 cytokines. IFN-gamma is secreted by TH1 cells, and is the main macrophage-activating cytokine.

Question 77

For this patient, you request that the lab perform indirect immunofluorescence using what substrate?
1 Monkey esophagus
2 Rat bladder
3 Guinea pig esophagus
4 Mouse epithelium
5 Hep-2 cells

Answer 77

This patient has pemphigus folicaceus, and indirect immunofluorescence works best on guinea pig esophagus.

Question 78

Which cytokine is the main macrophage-activating cytokine?
1 TNF
2 IFN-gamma
3 IL-4
4 IL-10
5 lymphotoxin

Answer 78

IFN-gamma is the main macrophage-activating cytokine, and is secreted by TH1 cells.

Question 79

Which cytokine is most important in recruiting neutrophils?
1 Interleukin-1
2 Interleukin-2
3 Interleukin-4
4 Interleukin-8
5 Interleukin-10

Answer 79

Interleukin-8

Chemotaxis is the process of cells moving through a gradient of towards increasingly higher concentrations. IL-8 has activating and chemoattractant properties on neutrophils.

Question 80

All of the following statements are true regarding cells of the innate immune system EXCEPT:
1 Neutrophils have receptors for IgG
2 Basophils are a type of granulocyte, as are neutrophils
3 IL-5 downregulates the functions of eosinophils
4 Langerhans cells are poorly phagocytic
5 Langerhans cells express CD1 on their surface

Answer 80

Neutrophils, eosinophils, and basophils are collectively known as granulocytes. Neutrophils have receptors for IgG and complement. IL-5 enhances all functions of eosinophils. Langerhans cells are dendritic cells found in high concentration in epithelial surfaces and some areas of lymph nodes and spleen. They have a high density of class II MHC molecules and express CD1 on their surface. They are poorly phagocytic.

Question 81

Elaboration of which of the following cytokines is characteristic of TH2 response?
1 Interferon-8 (gamma)
2 Interleukin-1
3 Interleukin-2
4 Interleukin-4
5 Interleukin-12

Answer 81

Interleukin-4 (IL-4) is a cytokine involved in B-cell proliferation. Along with IL-5 and IL-13, IL-4 is classified as a TH2 cytokine.

Question 82

Efalizumab is an antibody which is directed against LFA1 on the T-cell, blocking this molecule’s interaction with:
1 CD40
2 B7
3 LFA3
4 ICAM-1
5 P-selectin

Answer 82

ICAM-1 on the antigen presenting cell interacts with LFA1 on the T-cell. By interrupting this interaction, T-cell activation is blocked by preventing the pairing of LFA1 with ICAM-1. This prevents costimulatory signals from being given to the T-cell. T-cell ability to traffic into the skin is also inhibited in the arrest stage of trafficking.

Question 83

Natural killer (NK) cells eliminate infected cells in all of the following ways except:
1 NK cells adhere to and kill target cells coated with IgG
2 NK cells secrete perforins
3 NK cells secrete granzyme
4 NK cells secrete myeloperoxidase
5 NK cells do not target cells expressing major histocompatibility (MHC) class I molecules

Answer 83

4. NK cells secrete myeloperoxidase

NK cells focus on the destruction of infected or malignant cells. They achieve this via recognition of IgG on target cells, the so-called ‘antibody-dependent cellular toxicity.’ NK cells also eliminate cells by secreting perforin, which makes holes in the cell membrane, through which granzyme is injected. Granzyme induces apoptosis by activating the caspase cascade. In addition, NK cells do not target cells expressing MHC class I molecules on their surface; some virus downregulate MHC class I molecules to evade recognition by cytotoxic T cells, which may make them susceptible to NK cell attack. Neutrophils kill ingested organims using myeloperoxidase.

Question 84

Dermatitis Herpetiformis is most commonly associated with which HLA?
1 HLA-DR3
2 HLA-B27
3 HLA-B8
4 HLA-Bw35
5 HLA-DQ(A1*0501, B1*02)

Answer 84

HLA-DQ (A1*0501, B1*02) genes are present on 90% of all patients with Dermatitis Herpetiformis. The remainder of patients have the HLA-DQ8 gene. Other associations include: HLA-B8, HLA-DR3 and DR5/DR7.

Question 85

Which of the follwing is a chemotactic factor for eosinophils?
1 TNF
2 IL2
3 C5a
4 Plasminogen activator
5 IL8

Answer 85

Eosinophil chemotactic factors include all of the following: Histamine, soluble immune complexes, C5a, and HETE

Question 86

Which is not a feature of mast cells?
1 Expresses c-kit
2 Responds to RANTES
3 Produces IL-8
4 Produces prostaglandin D2
5 Stains with napththol chloro-acetate esterase

Answer 86

2 Responds to RANTES

Mast cells are an integral portion of immediate type hypersensitivity. RANTES is a chemoattractant for eosinphils, not mast cells.

Question 87

The antibody produced in the early stages of antibody responses is:
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM

Answer 87

IgM is the antibody produced in the early stages of antibody responses. It is a pentamer which can agglutinate antigen and active the classic complement pathway. IgG is the antibody that can cross the placenta and the most common antibody found in circulation. IgA is found in mucous membrane secretions and is able to agglutinate antigens and activate the alternate but not the classic complement pathway. IgD is not found in circulation other than in hyper-IgD syndrome, an autosomal recessive disorder caused by mutations in the mevalonate kinase gene. A significant elevation of serum IgD is seen in 95% of these patients. IgE is an anaphylactic antibody that is involved in nearly all immediate allergic and anaphylactic type reactions.
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Question 88

Pemphigus is associated with which HLA type(s)?
1 HLA-DRw6
2 HLA-B8
3 HLA-B51
4 All of these answers are correct
5 None of these answers are correct

Answer 88

Pemphigus is associated with HLA-DR4 or DRw6.
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Question 89

Which common contact allergen is detected via the dimethylglyoxime test?
1 Benzocaine
2 Chromates
3 Formaldehyde
4 Nickel
5 Rhus

Answer 89

Nickel is found in virtually all metals of common use. It is the most common sensitizer in women, and is detected by the dimethylglyoxime test.
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Question 90

The human major histocompatibility complex (MHC) is located on chromosome:
1 2
2 6
3 9
4 11
5 17

Answer 90

The MHC is highly polygenic and polymorphic, and this contributes to the ability of of the immune system to respond to a multitude of different and rapidly evolving pathogens. The MHC is located on chromosome 6 in humans.

Question 91

Histamine is a biologic amine produced by which of the following cells?
1 Monocytes
2 Eosinophils
3 Basophils
4 Platelets
5 Basophils and Platelets

Answer 91

In the skin, histamine is mainly contained within the granules of dermal mast cells. Histamine is present in mast cells, basophils, and platelets.

Question 92

A 5 year old patient is seen at a tertiary referral center for evaluation of a complex syndrome. Ultimately, he is diagnosed with IPEX syndrome (immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome.) What gene is mutated in IPEX syndrome?
1 FOXP3
2 LFA-3
3 TGF-beta
4 B7
5 Mac-1

Answer 92

IPEX syndrome is a rare x-linked disorder. Mutation of FOXP3 results in absence of regulatory T cells and is the cause of this syndrome, which includes immune dysregulation, polyendocrinopathy, and enteropathy.

Question 93

This skin disease has been shown to be associated with reduced Beta 2 defensin. The diagnosis is:
1 Atopic dermatitis
2 Psoriasis
3 Lepromatous leprosy
4 Tuberculoid leprosy
5 Subacute cutaneous lupus erythematosus

Answer 93

The answer is atopic dermatitis. Cathelicidin 37 (LL-37) and Human Beta 2 Defensins (HBD-2) have been reported reduced in atopic dermatitis and normal or elevated in psoriasis. This could be one factor that predisposes atopics, but not psoriatics to bacterial and viral infections.

Question 94

The classical complement pathway:
1 Can be activated in the absence of antibody
2 Can be activated by IgG4
3 Can be activated by IgM
4 Includes C3 and factor B
5 Does not cause membrane damage

Answer 94

The classical complement pathway is activated by antigen-antibody complexes, while the alternate complement pathway can be activated in the absence of antibody. IgM and IgG are capable of activating the classical pathway, but IgG4 does not activate complement. The proteins of the classical pathway are C1, C2, C3, and C4. Factor B, Factor D, properdin, and C3 are proteins in the alternate pathway. Biologic activities of complement include opsonization, chemotaxis, anaphylaxis, immune complex solubilization, membrage damage, and B cell activation.
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Question 95

Relapsing polychondritis is an autoimmune disease associated with immunity to which type of collagen?
1 I
2 II
3 III
4 IV
5 VII

Answer 95

Relapsing polychondritis has been reported to have autoantibodies to type II collage.
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Question 96

Which of the following is an example of a delayed hypersensitivity reaction?
1 Allergic contact dermatitis
2 Anaphylaxis
3 Latex allergy
4 Transfusion reaction
5 Serum sickness

Answer 96

There are 4 types of Hypersensitivities: (“ACID”) Type I: Anaphylactic and Atopic: Examples - Urticaria, Asthma, and Allergic Rhinitis Type II: cytotoxic: examples - Transfusion reactions, ABO incompatibility, Rh disease (erythroblastosis fetalis), Autoimmune reactions, Hemolytic disease of newborn, Goodpasture’s syndrome Type III: Immune complex, Serum sickness, and arthrus reactions: examples -PAN, glomerulonephritis, SLE, Rheumatoid arthritis, and serum sickness Type IV: Delayed (cell-mediated)typesL examples -TB skin test, transplant rejection, contact dermatitis, interactions and skin repsonsiveness to bacteria, fungi, viruses, and protozoa, photo-allergies, insect bites, etc
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Question 97

Major histocompatibility complex (MHC) Class I molecules:
1 Are inducible on keratinocytes
2 Complexed with antigen trigger cytotoxic T cells
3 Are recognized by receptors on CD4+ T cells
4 Bear peptides derived from pathogens taken up into vesicles
5 All of the above

Answer 97

MHC Class I molecules are present on all nucleated cells. They are recognized by receptors on surfaces of CD8+ T cells, and, when complexed with antigen, trigger cytotoxic T cells. The other statements apply to MHC Class II molecules.

Question 98

What is the best screening test for hereditary angioedema?
1 C1 esterase
2 C4
3 CH50
4 C2
5 C3

Answer 98

C4 is the best screening test for hereditary angioedema (Quinke’s edema). There are two types of hereditary angioedema. In type I, there are low antigenic and functional levels of a NORMAL C1 esterase inhibitor protein. In type II, there is a normal or elevated level of a DYSFUNCTIONAL C1 esterase inhibitor. The low C4 level is a result of continuous activation and consumption of complement components.

Question 99

The major histocompatibility complex (MHC)consists of a linked set of genes encoding for MHC Class I, Class II, Class III, and Class IB. Which of the following is/are true:
1 Class II molecules are present on all nucleated cells
2 Class I molecules are present on erythrocytes
3 Class I molecules are expressed on B8 cells, monocytes and dendritic cells
4 The level of Class I and II expression can be modulated by cytokines
5 The MHC region is located on chromosome 17 in humans

Answer 99

The major hisotcompatibility complex (MHC) consists of a linked set of genes encoding for MHC Class I, Class II, Class III, and Class IB. The level of Class I and II expression can be modulated by cytokines.

Question 100

1 Essential mixed cryoglobulinemia
2 Rheumatoid arthritis
3 Relapsing polychondritis
4 Wegener�s granulomatosis
5 Dermatomyositis

Answer 100

Hepatitis C infections can present as urticaria or papable purpura and cryoglobulinemia.

Question 101

Mononuclear phagocytes residing in tissues:
1 Are called macrophages
2 Phagocytose foreign antigens and degrade them into peptides
3 Present antigen to T-cells
4 Produce cytokines, which recruit other inflammatory cells
5 All of the above

Answer 101

Mononuclear phagocytes are components of the innate immune system. Once in tissues they are called macrophages. All of the above are correct.

Question 102

A patient had antibodies to desmoglein 3, but no antibodies to desmoglein 1 or desmplakin. The likely diagnosis is:

1 Pemphigus vulgaris
2 Pemphigus foliaceous
3 Bullous pemphigoid
4 Dermatitis herpetiformis
5 Erythema multiforme

Answer 102

The answer is pemphigus vulgaris, which typically has autoantibodies to desmoglein 3. While mixed forms of pemphigus can occur, the histology in this case confirmed pemphigus vulgaris.

Question 103

Eosinophils are typically seen in the cutaneous infiltrate of:
1 Krabbe�s disease
2 Kaposiform hemangioendothelioma
3 Kawasaki�s disease
4 Kimura�s disease
5 Ki-1 lymphoma

Answer 103

Eotaxin, which attracts eosinophils, is produced by T cells in Kimura�s disease.

Question 104

Langerhans cell adhesion to keratinocytes is mediated by what adhesion molecule?
1 E-cadherin
2 N-cadherin
3 Desmoglein 3
4 P-cadherin
5 B7

Answer 104

Langerhans cells are found in the epidermis and on mucosal surfaces. After antigen exposure and activation, they migrate to regional lymph nodes where they mature into antigen presenting cells. Adhesion to keratinocytes in the epidermis is mediated by e-cadherin.

Question 105

Proteins in the alternate complement pathway include:
1 Factor B
2 properdin
3 C3
4 Factor B and properdin
5 Factor B, properdin and C3

Answer 105

Proteins in the alternate complement pathway are Factor B, Factor D, properdin, and C3. The alternate complement pathway is active against pathogenic microorganisms, virus-infected cells, and neoplastic cells. The proteins of the classical pathway are C1, C2, C3, and C4.

Question 106

The most likely target for exfoliative toxin A in bullous impetigo is:
1 Desmoglein 3
2 Laminin 5
3 Desmoglein 1
4 Collagen VII
5 Cesmocollin

Answer 106

Desmoglein 1, the dominant target antigen of the autoantibody involved in pemphigus foliaceus, is also the target of the exfoliative toxin of group II staphylococcus aureus that is usually responsible for bullous impetigo.

Question 107

Chronic idiopathic urticaria is associated with which HLA type(s)?
1 HLA-DR4
2 HLA-DRB4 53
3 HLA-DQ8
4 all of the above
5 none of the above

Answer 107

Chronic idiopathic urticaria is associated with HLA -DR4, -DRB4 53, and -DQ8.

Question 108

Which of the following is true of Langerhan cells?
1 They are the primary antigen presenting cell in the epidermis
2 They are primarily involved in the innate immune response
3 They do not express the CD1a marker
4 They contain intranuclear birbeck granules
5 They are increased on the palms, soles, genitalia, and buccal mucosa

Answer 108

Langerhans’ cell function primarily in the afferent limb of the immune response by providing for the recognition, uptake, processing, and presentation of antigens to sensitized T lymphocytes. They are normally found scattered among keratinocytes of the stratum spinosum, or prickle cell layer. of the epidermis. They can be stained with CD1a or S-100. They originate in the bone marrow. They contain intracytoplasmic Birbeck granules.

Question 109

This lesion is hypoesthetic and is associated with which of the following:
1 Gamma interferon
2 Interleukin 2
3 Interleukin 12
4 All of these answers are correct
5 None of these answers are correct

Answer 109

The lesion is high immune or tuberculoid leprosy, which is associated with TH1 cytokines including IFN-gamma, IL2, IL12, IL15, IL18 and IL23.

Question 110

Anti-Ro (SS-A) antibodies are most commonly found in:
1 Mixed connective tissue disease
2 Eosinophilic fasciitis
3 Drug-induced systemic lupus erythematosus
4 Homozygous C2 deficiency
5 Neonatal lupus erythematosus

Answer 110

Ro 60 kDa autoantigen is a major target for patients with SLE and Sj�gren�s syndrome. Neonatal lupus occurs in newborns of mothers with anti-Ro antibodies and leads to children with photosensitive skin lesions and a cardiac conduction defect, a third degree heart block.

Question 111

An elderly gentleman with metastatic colon cancer is prescribed erlotinib, an epidermal growth factor receptor monoclonal antibody. What is the most common cutaneous finding seen as a result of this class of medication?
1 Acneiform eruption
2 Acral erythema
3 Morbilliform eruption
4 Hypotrichosis
5 Urticaria

Answer 111

Erlotinib, along with cetuximab and gefitinib, are epidermal growth factor receptor inhibitors that are used for the treatment of multiple visceral malignancies, including metastatic colon cancer. They have all been associated with an acneiform eruption.

Question 112

Which of the following cytokines has been shown to be critical for epidermal acanthosis in psoriasis?
1 TNF-alpha
2 TGF-beta
3 IL-2
4 FGF
5 IL-22

Answer 112

IL-22 has recently been shown to be critical in causing epidermal acanthosis. Interleukin (IL)-23, a cytokine involved in the development of IL-17-producing T helper cells (Th17 cells), was found to have a potential function in the pathogenesis of psoriasis. IL-22 is preferentially produced by Th17 cells and mediates the acanthosis induced by IL-23. IL-23 can directly induce the production of IL-22 in human naive T cells. Furthermore, IL-22 mediates IL-23-induced acanthosis and dermal inflammation through the activation of Stat3.

Question 113

Which of the following is not true about the effects of ultraviolet radiation on the immune system?
1 UV radiation causes an increase in number of Langerhans cells in the epidermis
2 UV radiation causes nuclear DNA damage
3 Effects can be demonstrated by the example of reactivation of latent herpes simplex infection after sun exposure
4 UV radiation acts to suppress the immune system both locally and systematically
5 Effects can be demonstrated by the ability of an antigen to induce an allergic hypersensitivity reaction when applied to skin which has been exposed to low doses of UV radiation

Answer 113

Effects of UV radiation on the immune system: UV radiation inhibits function of Langerhans cells (A-False). It causes DNA damage, can reactivate HSV, suppresses immune system, and can induce allergic hypersensitivity reaction

Question 114

This patient developed an acute vesicular rash after eating a mango. She has returned for a routine follow-up. She needs to be careful of exposure to:
1 Ginkgo fruit
2 Croton
3 Ragweed
4 Tea tree oil
5 All of these answers are correct

Answer 114

Patients allergic to the peel of a mango can also be allergic to other plants/products of the Anacardiaceae family. Cross-reactions can occur with exposure to any plants of the genus Toxicodendron, to the oil from the cashew nut shell, to the Brazilian pepper tree, to lacquer from the Japanese lacquer tree, to ink from the Indian marking nut, and to the fruit pulp of the ginkgo tree, and others.

Question 115

Allergic contact dermatitis is caused by T-cell response to topical exposure to compounds that form complexes with host proteins (haptens). Which cell is responsible for initial sensitization of the T-cells?
1 Melanocyte
2 Langerhans Cell
3 B-cell
4 Mast Cell
5 Macrophage

Answer 115

The Langerhans cell phagocytizes the haptens in the epidermis or dermis, begins the process of maturation and migrates to the regional lymph node, where na�ve T-cells are educated to expand to a clone of CLA positive memory T-cells. These cells then can expand and extravasate with subsequent exposure to the same allergen. Melanocytes, B-cells, Mast cells and macrophages are not involved in the sensitization process of allergic contact dermatitis.

Question 116

Which of the following causes a photoallergic contact dermatitis that is exacerbated by UVA radiation?
1 Ascorbic acid
2 Titanium dioxide
3 Oxybenzone
4 Zinc oxide
5 Dihydroxyacetone

Answer 116

Oxybenzone is the most common sunscreen agent causing photoallergic contact dermatitis. Patients sensitive should be instructed to avoid sunscreens containing oxybenzone.

Question 117

A previously healthy child presents with palpable purpura, arthritis, and vomiting. You suspect a hypersensitivity vasculitis characterized by:
1 Perivascular IgA
2 P-ANCA autoantibodies
3 Granulomas and eosinophilia
4 Infiltration of destruction of vessels by atypical lymphocytoid and plasmacytoid cells
5 Nectrotizing granulomatous vasculitis

Answer 117

The child has findings of Henoch-Schonlein purpura, a hypersensitivity vasculitits that presents clinically with a triad of purpura, joint pain, and GI complaints. Histologically it is characterized by perivascular deposition of IgA.

Question 118

A 33 year old patient presents with recurrent swelling of the lips, oropharynx, and face. A diagnosis of angioedema is made. Which marker is measured to differentiate between hereditary angioedema and acquired angioedema?
1 C1q
2 CR1
3 C-reactive protein
4 Fibrin split products
5 C5a

Answer 118

Angioedema is characterized by swelling of the soft tissues of the face and neck, often in association with a known trigger, such as a medication. Urticarial plaques are also commonly seen. In hereditary angioedema C1q levels are normal, while in acquired angioedema, they are normal.

Question 119

A patient with Stage 3 mycosis fungoides is referred to a tertiary referral center for further management. Denileukin diftitox is offered as a potential therapy. This medication binds to what receptor on the T cell?
1 IL-2
2 MHC II
3 CD20
4 TNF-alpha
5 CD19

Answer 119

Denileukin diftitox is a fusion of a fragment of diphtheria toxin and IL-2. It binds to high affinity IL-2 (CD25) receptors on T cells. As the medication is internalized, the toxin leads to cell death. This medication has been approved for cutaneous T cell lymphoma.

Question 120

Which of the following best describes the mechanism of action for infliximab?
1 Inhibition of calcineurin-mediated dephosphorylation of transcription factors
2 Inhibition of retinoic acid 4-hydroxylase activity
3 Inhibition of tumor necrosis factor alpha activity
4 Selective elimination of activated T cells via binding to high affinity IL-2 receptor
5 Selective T-cell up-regulation of IL-4 and IL-5 production

Answer 120

Infliximab is a monoclonal antibody given intravenously that binds to membrane-bound and soluble TNF-alpha.

Question 121

Which antibody can bind the FcER1 portion of mast cells, basophils, Langerhans cells, dermal dendritic cells?
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM

Answer 121

IgE is an anaphylactic antibody that is involved in nearly all immediate allergic and anaphylactic type reactions and commonly seen in elevated levels in patients with atopic dermatitis. Mast cells, basophils, Langerhans cells, dermal dendritic cells as well as monocytes from atopic individuals all express high-affinity FcERI receptor which can bind IgE. More recently, it became clear that can bind monomeric IgE via the high-affinity Fc�RI IgG is the antibody that can cross the placenta and the most common antibody found in circulation. IgA is found in mucous membrane secretions and is able to agglutinate antigens and activate the alternate but not the classic complement pathway. IgD is not found in circulation other than in hyper-IgD syndrome, an autosomal recessive disorder caused by mutations in the mevalonate kinase gene. A significant elevation of serum IgD is seen in 95% of these patients. IgM is the antibody produced in the early stages of antibody responses. It is a pentamer which can agglutinate antigen and active the classic complement pathway.
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Question 122

A patient with severe chronic psoriasis has failed multiple systemic therapies. Alefacept is initiated for a three month trial. This medication induces apoptosis of T cells by binding to what T cell receptor molecule?
1 CD2
2 CD45RO
3 LFA-3
4 CTLA-4
5 p40

Answer 122

Alefacept is a human fusion protein of LFA-3 with Fc protion of IgG1. It binds CD2 on CD45RO memory effector T cells, thus blocking the 2nd signal of T cell activation and leading to apoptosis. A provider must monitor the CD4 T cell count while a patient is on this medication.

Question 123

Major histocompatibility complex class I molecules bind to:
1 Peptides derived from proteins synthesized and degraded in the cytosol
2 Peptides derived from proteins degraded in endocytic vesicles
3 Peptides external to the cell membrane
4 Immunoglobulin E
5 None of these answers are correct

Answer 123

Major histocompatibility complex (MHC) class I molecules bind to peptides derived from proteins synthesized and degraded in the cytosol. They present these processed peptides to CD8+ T-cells. MHC class II molecules bind stably to peptides derived from proteins degraded in endocytic vesicles. CD4+ T-cells recognize the MHC class II molecules. Immune activation against the foreign antigens or pathogens taken up by the cell is the result of these interactions. Peptides external to the cell are not recognized by MHC molecules. IgE does have a receptor on the cell surface, especially basophils and mast cells, but is not recognized by the MHC complex.
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Question 124

Which of the following features of IgG is true?
1 IgG is not an opsonizing antibody
2 IgG is the only class of immunoglobulin that can pass through the placenta
3 IgG cannot activate the complement cascade
4 IgG represents 15% of the total protein in serum
5 IgG is the second immunoglobulin synthesized by the fetus

Answer 124

IgG opsonizes bacteria, fixes complement, neutralizes bacterial toxins and viruses, crosses the placenta. It has the highest serum concentration of all immunoglobulins.

Question 125

The best screen for classical pathway complement deficiency or dysfunction is:
1 CD4/CD8 ratio
2 CH50
3 C2 esterase levels
4 Total C4 levels
5 Serum electophoresis

Answer 125

The appropriate screening test for a complement deficiency is the CH50. The CH50 will detect deficiencies in the classical pathway and membrane attack pathways.

Question 126

The most common autoimmune disorder in patients with chronic hepatitis C infection is:
1 Autoimmune thyroiditis
2 Idiopathic thrombocytopenic purpura
3 Rheumatoid arthritis
4 Sj�gren�s syndrome
5 Systemic lupus erythematosus

Answer 126

Autoimmune thrombocytopenia has been reported with hepatitis C infection but not as commonly as autoimmune thyroiditis.

Question 127

Purpuric contact dermatitis is most likely to be associated with:
1 Nickel
2 Formaldehyde
3 P-phenylenediamine
4 Propylene glycol
5 Sorbic acid

Answer 127

Textile dermatitis has been reported to be associated with purpuric contact dermatitis.

Question 128

Which paraprotein is found most commonly in patients with pyoderma gangrenosum?
1 IgG
2 IgA
3 IgM
4 IgE
5 IgD

Answer 128

IgA paraproteinemia has been reported in over 10-18% of pyoderma gangrenosum.

Question 129

With which HLA type is psoriasis most definitively linked?
1 HLA-B51
2 HLA-B8
3 HLA-DR4
4 HLA-DR3
5 HLA-Cw6

Answer 129

Psoriasis is linked with HLA-Cw6. Patients with this HLA type have a relative risk of having psoriasis that is 9-15 times normal.

Question 130

A 26 year-old man presents with a history of recurrent episodes of targetoid, erythematous, edematous macules, patches, and plaques on the arms, legs, palms, and soles. The most likely etiologic agent is:
1 Parvovirus B19
2 Herpes simplex virus
3 Coxsackievirus
4 Cytomegalovirus
5 Human immunodeficiency virus

Answer 130

This description of the skin disorder is compatible with either erythema multiforme or erythema elevatum diutinum, both of which have been reported in association with HSV.

Question 131

Which monoclonal gammopathy is most commonly associated with erythema elevatum diutinum?
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM

Answer 131

A report of 13 patients indicated IgA is most commonly associated with EED.

Question 132

The most useful pair of immunohistochemical stains to distinguish between Dermatofibroma protuberans (DFSP) and a fibrous histiocytoma would be:
1 Synaptophysin, chromogranin
2 CD34, factor XIIIa
3 CD34, CD31
4 CD31, CD3
5 Vimentin, synaptophysin

Answer 132

Dermatofibroma, the more common benign histiocytoma, is usually CD34 negative and factor XIIIa positive. DFSP is usually CD34 positive and factor XIIIa negative.

Question 133

Sensation is intact in this lesion, but a Fite stain is positive. This lesions is associated with which of the following:
1 IL-4
2 IL-5
3 IL-10
4 All of these answers are correct
5 None of these answers are correct

Answer 133

The lesion is low immune or lepromatous leprosy, which is associated with TH2 cytokines including IL-4, IL-5, IL-10, and IL-13.

Question 134

The main cytokine secreted by Th1 CD8+ effector T-cells is:
1 IL-1
2 IL-2
3 IFN-gamma
4 IL-4
5 IL-5

Answer 134

Interferon-gamma is the main cytokine secreted by Th1 CD8+ effector T-cells and is active in blocking viral replication. IL-2 is also released in Th1 reactions and causes T cell proliferation and differentiation, macrophage, NK, & Tc cell activation. It also acts as a Th1 autocrine growth factor. IL-1 is a pro-inflammatory cytokine and a pyrogen. IL-4 is a B-cell growth factor and active in signaling isotope switching from IgM to IgE. IL-5 is an eosinophil growth factor. Both IL-4 and -5 are secreted by Th2 T-cells.

Question 135

Linear IgA disease is most closely associated with which of the following medications?
1 Erythromycin
2 Vancomycin
3 Streptomycin
4 Azithromycin
5 Clarithromycin

Answer 135

Vancomycin is an antibiotic frequently used in subjects allergic to penicillin. It has been reported to produce subepidermal blistering disease with linear IgA deposits.

Question 136

This patient had antibodies to 180 kd antigen. The likely diagnosis is:
1 Bullous pemphigoid
2 Pemphigus vulgaris
3 Pemphigus foliaceous
4 Erythema multiforme
5 Bullous lichen planus

Answer 136

The answer is bullous pemphigoid, which shows a characteristic antibasement membrane antibody to Bp180.

Question 137

Which of the following cytokines is a general down-regulator of TH1 immunity?
1 IL-4
2 IL-5
3 IL-10
4 TNF
5 IFN-gamma

Answer 137

IL-4 is a B cell growth factor. IL-5 is an eosinophil growth factor. IL-10 is a general down-regulator of TH1 immunity. TNF and IFN-gamma are TH1 cytokines, not TH2 cytokines. IFN-gamma is secreted by TH1 cells, and is the main macrophage-activating cytokine.

Question 138

A patient with chronic atopic dermatitis is found to have elevated IgE levels. Which cytokine promotes isotype switching to IgE?
1 IL-4
2 IL-6
3 IL-5
4 Interferon-gamma
5 IL-23

Answer 138

In a typical humoral response, isotype switching occurs subsequent to exposure to antigen. Switching is regulated by T cell derived cytokines. IgG is promoted by IL-4, IL-6, IL-2 and IFN-gamma. IgA is promoted by IL-5 and TGF-beta. IgE is promoted by IL-4.

Question 139

The immunoglobulin most commonly found in mucous secretions is:
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM

Answer 139

IgA is found in mucous membrane secretions and is able to agglutinate antigens and activate the alternate but not the classic complement pathway. IgG is the antibody that can cross the placenta and the most common antibody found in circulation. IgD is not found in circulation other than in hyper-IgD syndrome, an autosomal recessive disorder caused by mutations in the mevalonate kinase gene. A significant elevation of serum IgD is seen in 95% of these patients. IgE is an anaphylactic antibody that is involved in nearly all immediate allergic and anaphylactic type reactions. IgM is the antibody produced in the early stages of antibody responses. It is a pentamer which can agglutinate antigen and active the classic complement pathway.
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Question 140

Which of the following cytokines is a general down-regulator of TH1 immunity?
1 IL-4
2 IL-5
3 IL-10
4 TNF
5 IFN-gamma

Answer 140

IL-4 is a B cell growth factor. IL-5 is an eosinophil growth factor. IL-10 is a general down-regulator of TH1 immunity. TNF and IFN-gamma are TH1 cytokines, not TH2 cytokines. IFN-gamma is secreted by TH1 cells, and is the main macrophage-activating cytokine.

Question 141

A patient with chronic atopic dermatitis is found to have elevated IgE levels. Which cytokine promotes isotype switching to IgE?
1 IL-4
2 IL-6
3 IL-5
4 Interferon-gamma
5 IL-23

Answer 141

In a typical humoral response, isotype switching occurs subsequent to exposure to antigen. Switching is regulated by T cell derived cytokines. IgG is promoted by IL-4, IL-6, IL-2 and IFN-gamma. IgA is promoted by IL-5 and TGF-beta. IgE is promoted by IL-4.

Question 142

The immunoglobulin most commonly found in mucous secretions is:
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM

Answer 142

IgA is found in mucous membrane secretions and is able to agglutinate antigens and activate the alternate but not the classic complement pathway. IgG is the antibody that can cross the placenta and the most common antibody found in circulation. IgD is not found in circulation other than in hyper-IgD syndrome, an autosomal recessive disorder caused by mutations in the mevalonate kinase gene. A significant elevation of serum IgD is seen in 95% of these patients. IgE is an anaphylactic antibody that is involved in nearly all immediate allergic and anaphylactic type reactions. IgM is the antibody produced in the early stages of antibody responses. It is a pentamer which can agglutinate antigen and active the classic complement pathway.
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Question 143

The target antigen of chronic bullous disease of childhood is:
1 BPAG 1 9230 kd BPAG)
2 97 kd LAD-1 (a component of BPAG2)
3 Collagen type VII
4 Alpha 6 beta 4 integrin
5 Plectin

Answer 143

This rare chronic bullous disease of childhood is a subepidermal blistering disease with a homogeneous IgA deposits at the epidermal basement membrane. This occurs in children usually less than 5 years of age.

Question 144

Which cytokine is predominantly responsible for the Jarish-Herxheimer reaction?
1 TNF-alpha
2 IL-2
3 IL-5
4 IL-6
5 IL-12

Answer 144

The Jarish-Herxheimer reaction may occur after the initiation of treatment of many systemic infections including syphillis. It is an indirect drug induced effect caused by bacterial endotoxins or microbial antigens liberated by the destruction of micro-organisms. Clinical manifestations may include fever, lymphadenopathy, arthralgias, and exacerbation of pre-existing cutaneous lesions. Tumor necrosis factor-alpha is the primary cytokine that mediates this reaction.

Question 145

MHC Class II molecules are present on which of the following cell types:
1 B cells
2 T cells
3 NK cells
4 Mast cells
5 All of the above

Answer 145

MHC Class II molecules are on B cells, monocytes, dendritic cells, and are inducible on keratinocytes and endothelial cells.

Question 146

This patient recently developed this rash. You decide to patch test her, but in the meanwhile you tell her to avoid:
1 Chamomile
2 Primin
3 Abietic acid
4 Benzocaine
5 Cinnamon

Answer 146

Cinnamon

This patient likely has a fragrance allergy. Patients allergic to fragrances also need to avoid certain spices like cinnamon.

Question 147

The endothelial ligand for cutaneous lymphocyte antigen (CLA) is:
1 Intercellular adhesion molecule 1 (ICAM-1)
2 L-selectin
3 E-selectin
4 Vascular cell adhesion molecule (VCAM-1)
5 Leukocyte functional antigen (LFA 3)

Answer 147

Cutaneous lymphocyte antigen (CLA) allow memory T cells to home to the skin, where it binds to its ligant E-selectin on cutaneous microvessels. Transmigration of memory T cells into the dermis, however, further requires interaction between leukocyte functional antigen 1 (LFA-1) and ICAM-1, and B-integrin very late antigen 4 (VLA-4) and VCAM-1. L-selectin is expressed on post-capillary venules in the lymph nodes and serves as the attachment points for naive T cells.

Question 148

Topical tacrolimus and pimecrolimus are used to treat atopic dermatitis and other inflammatory skin conditions. On which of the following ions is the inflammatory pathway blocked by these medications dependent?
1 Sodium
2 Potassium
3 Calcium
4 Selenium
5 Zinc

Answer 148

Calcium. Both pimecrolimus and tacrolimus penetrate cutaneous T-cells, forming a complex with calcineurin, which blocks the activation of NF-AT, thus blocking the transcription of a variety of genes with a resultant decrease in T-cell mediated inflammation. This pathway is calcium dependent. The other ions are not involved in this process.

Question 149

The gene for NEMO (NF-kappa bets essential modulator) is mutated in:
1 Papillon-Lef�vre syndrome
2 Pachyonychia congenital type II
3 Dyskeratosis congenital
4 Noonan�s syndrome
5 Incontinentia pigmenti

Answer 149

NEMO/IKK gamma is an essential component of the nuclear factor kappa B pathway, which is a common signaling pathway for many cytokines. Mutation in this pathway have been found to cause incontinentia pigmenti.

Question 150

All of the following statements regarding mast cells are true EXCEPT:
1 Mast cells reside near small blood vessels
2 Mast cells protect mucosal surfaces against pathogens
3 Mast cells release substances that affect vascular permeability
4 Mast cells have receptors for certain fragments of complement on their surface
5 None of the above (all are true)

Answer 150

Mast cells are the central cell in immediate-type hypersenstivity, and are very important in cutaneous inflammation. They reside near small blood vessles, and when activated release substances that affect vascular permeability. They orchestrate allergic responses and protect mucosal surfaces against pathogens. They have receptors for IgE and certain fragments of complement on their cell surface.

Question 151

IL-23 plays a critical role in the pathogenesis of psoriasis. Which of the following cytokines is critical for IL-23-mediated epidermal hyperplasia in psoriasis?
1 IL-2
2 IL-6
3 IL-12
4 TNF-alpha
5 IFN-gamma

Answer 151

IL-23 facilitates the differentiation and induces complete maturation of Th17 cells. Lesional psoriatic skin has increased levels of IL-23. IL-6 is essential for development of the IL-23-elicited responses and is required for the development of epidermlal hyerplasia.

Question 152

This disease is most associated with:
1 Gamma interferon
2 IL-4
3 IL-5
4 IL-13
5 None of these answers are correct

Answer 152

The answer is gamma interferon, which is the TH1 cytokine associated with a hyperproliferative epidermis and with micaceous scale as seen in psoriasis.

Question 153

The human leukocyte antigen that has the closet association with psoriasis is:
1 HLA-B51
2 HLA-DQ3
3 HLA-B27
4 HLA-Cw6
5 HLA-DR1

Answer 153

Human leukocyte antigens (HLA class I molecules) are designated A, B, and C and are present on all nucleated cells. Class I molecules present antigens including autoantigens to cytotoxic T cells.

Question 154

Herpes simplex virus-related erythema multiforme has been associated with an increased frequency of:
1 HLA-B7
2 HLA-B8
3 HLA-B13
4 HLA-B15
5 HLA-B27

Answer 154

Erythema multiforme associated with herpes simplex has been reported to have an increase of HLA-B15.

Question 155

Which of the following diseases does NOT respond with a Th1-type responses?
1 Leishmaniasis which self-resolves
2 Lepromatous Leprosy
3 Tuberculoid Leprosy
4 Allergic contact dermatitis
5 Psoriasis

Answer 155

Lepromatous leprosy is Th2 biased. The remaining conditions are Th1 predominant responses. Leishmaniasis which show strong cell-mediated immunity to the parasite and with self-resolving lesions are Th1 responses. In indolent/progressive leishmaniasis, a Th2 pattern is predominant.