Immunodermatology Flashcards
1- Treatment of this condition with IL-17 blockade has been shown to:
A. Increase the risk of Reversible Posterior Leukoencephalopathy syndrome
B. Worsen pre-existing multiple sclerosis
C. Increase risk for mucosal candidal infections
D. Cause hepatic fibrosis with long term use
E. Improve pre-existing inflammatory bowel disease
Correct choice: C. Increase risk for mucosal candidal infections
Explanation: Choice 1 is ustekinumab; choice 2 is TNF blockers; choice 4 is methotrexate
2- Blocking which cytokine would would be most beneficial in this condition?
A. IL-1
B. IL-10
C. IL-4
D. IL-5
E. IL-17
Correct choice: E. IL-17
Explanation: Nail psoriasis, characterized here by irregular nail pitting and distal onycholysis, responds to treatment against IL-17 including secukinumab, ixekizumab, and brodalumab
3- medical student with a family history of psoriasis and severe plaque psoriasis would like to know if there are any hereditary disease associations with the major histocompatibility complex. You recall that psoriasis has the following associations with HLA types:
A. HLA-Cw6/B13/B17/B27
B. HLA-DQ2/B8
C. HLA-B51
D. HLA-DR4/DQ8
E. HLA-DR3/DR4
Correct choice: A. HLA-Cw6/B13/B17/B27
Explanation: Psorsiasis is associated with a number of histcompatibility antigens. HLACw*0602– positive patients usually have a younger onset age, more severe psoriasis course, guttate or eruptive plaque psoriasis phenotypes, more frequent streptococcal throat carriage or infections, and streptococcal-associated psoriasis exacerbation. HLA-B27 is common in psoriatic arthritis, inflammatory bowel disease, and reactive arthritis. HLA-DQ2 is most frequently associated with dermatitis herpitformis. HLA-B51 most commonly with Behcet’s. HLA-DR4 and HLA-DQ8 have been linked to chronic urticaria. Pemphigus gestationis has been assocated with HLA-DR3/DR4.
4- Mononuclear phagocytes residing in tissues:
A. Are called macrophages
B. Phagocytose antibodies and degrade them into peptides
C. Present antigen to B-cells
D. Do not produce cytokines
E. Possess Fc receptor for IgE
Correct choice: A. Are called macrophages
Explanation: Mononuclear phagocytes are components of the innate immune system. Once in tissues they are called macrophages; when they are in the bloodstream they are referred to as monocytes. Macrophages phagocytose foreign antigens (NOT antibodies) and degrade them into peptides, present antigen to T-cells (NOT B-cells), produce cytokines (which recruit other inflammatory cells), and possess Fc receptor for IgG (NOT IgE).
5- Contact urticaria is a:
A. Type I hypersensitivity
B. Type II hypersensitivity
C. Type III hypersensitivity
D. Type IV hypersensitivity
E. Type V hypersensitivity
Correct choice: A. Type I hypersensitivity
Explanation: Contact urticaria is an example of a type I hypersensitivity reaction. The classic example is a latex-induced contact urticaria. Type I reactions (immediate hypersensitivity reactions) involve immunoglobulin E (IgE)–mediated release of histamine and other mediators from mast cells and basophils. Contact urticaria is not a Type II, III, or IV hypersensitivity reaction. There is no Type V hypersensitivity reaction.
6- Which of the following cell types induce susceptibility to tumor growth?
A. Suppressor T-cells
B. NK cells
C. Helper T-cells
D. Mast cells
E. Langerhans cells
Correct choice: A. Suppressor T-cells
Explanation: The suppressor T-cells induce susceptibility to tumor. These cells appear to arise in UV-irradiated hosts prior to tumor developing, and play a role in carcinogenesis.
7- A 14-year-old male presents with a severe eczematous dermatitis. His mother states that his skin has been a problem since he was an infant. Acute atopic dermatitis is associated with which of the following cytokine profiles?
A. Th1: IFN-γ, IL-2, IL-3
B. Th1: IL-1, TNF-β
C. Th2: TNF-β, IL-4
D. Th2: IL-4, IL-5, IL-13
E. Th2: IL-2, TNF-β
Correct choice: D. Th2: IL-4, IL-5, IL-13
Explanation: The acute atopic dermatitis immune profile is Th2-cytokine-based, with IL4, IL-5 and IL-13 as prominent aspects. In chronic atopic dermatitis has Th1 cytokines (IFN-γ, IL-12) dominate. Other listed cytokines are not prominent in acute atopic dermatitis.
8- A child develops lesions see below. How can you differentiate the genetic form from the drug- induced form?
A. Porphyrins
B. Direct immunofluorescence
C. Indirect immunofluorescence
D. Histologic pattern
E. ELISA
Correct choice: A. Porphyrins
Explanation: Porphyria cutanea tarda (PCT) can be due to a genetic mutation in UROD. Pseudo- PCT is most commonly secondary to drugs such as naproxen, NSAIDs, tetracycline, furosemide, and hemodialysis. The main differentiating factor is that urine, serum, and fecal porphyrins are normal in pseudo-PCT. Pseudoporphyria can look histologically exactly like PCT with DIF with IgG, IgM, IgA, C3 at DEJ and around vessels.
9- In a patient with IPEX (immunodysregulation, polyendocrinopathy, enteropathy, X-linked) syndrome, which of the following T-cell lines are affected?
A. Th17
B. Th1
C. Th2
D. Cytotoxic T-cells
E. Regulatory T-cells
Correct choice: E. Regulatory T-cells
Explanation: FOXP3 is the most often mutated gene in IPEX syndrome. FOXP3 is critical in the function of regulatory T-cells. The other T cell lines are not directly affected in IPEX syndrome.
10- A 32 year-old woman presents with meningitis and palpable purpura. A diagnosis of meningococcemia is confirmed via culture of cerebrospinal fluid. Which complement component is most likely to be deficient in this patient?
A. C1
B. C2
C. C3
D. C4
E. C5
Correct choice: E. C5
Explanation: Patients with deficiencies of late complement components (C5-9) are at increased risk of meningococcemia due to Neisseria. Early complement component (C1-4) deficiencies are not associated with increased risk of meningococcemia.
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?
A. IL-2
B. IL-12
C. IL-17A
D. TNF-alpha
E. IFN-gamma
Correct choice: C. IL-17A
Explanation: 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.
Psoriasis is a chronic systemic inflammatory disease causing erythematous and scaly skin plaques; up to 30% of patients with psoriasis develop Psoriatic Arthritis (PsA), which is characterized by inflammation and progressive damage of the peripheral joints and/or the spine and/or the entheses. The pathogenic mechanisms driving the skin disorder in psoriasis and the joint disease in PsA are sustained by the activation of inflammatory pathways that can be overlapping, but also, at least partially, distinct. Cytokines members of the IL-23/IL-17 family, critical in the development of autoimmunity, are abundantly expressed within the cutaneous lesions but also seem to be involved in chronic inflammation and damage of the synovium though, not in all patients. IL-2, IL-12, TNF- alpha, and IFN-gamma are not critical in playing an interactive role with IL-23 in psoriasis.
12- Patients with the above condition should be evaluated for what immunodeficiency?
A. C5-9
B. IgM
C. C3
D. B2-integrin
E. Immunoglobulin
Correct choice: A. C5-9
Explanation: This is a photo of disseminated gonococcemia, which can be associated with a deficiency of C5-9. This deficiency increases susceptibility to Neisseria.
C3 and C4 are decreased in active systemic lupus erythematosus, especially when the kidneys are involved. They can also be decreased in hypocomplementemic urticarial vasculitis. Decreased IgM is associated with Wiskott–Aldrich. Leukocyte adhesion 1 deficiency is associated with a B2- integrin deficiency. Bruton’s agammaglobulinemia is associated with a decrease in immunoglobulin due to decreased mature B cells.
13 -The immunoglobulin most commonly found in mucous secretions is:
A. IgA
B. IgD
C. IgE
D. IgG
E. IgM
►A
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.
14- A 24 year old female patient is referred for management of chronic idiopathic urticaria. Many cases of this disease are associated with autoantibodies against what?
A. IgE receptor
B. Tryptase
C. Histamine receptor
D. TNF-alpha receptor
E. IL-6 receptor
►A
Many cases of idiopathic urticaria have circulating autoantibodies directed against the chain of high affinity IgE receptor on the mast cell surface.
15- The pharmacologic activity of tacrolimus includes:
A. Phosphorylation of NFAT (nuclear factor of transcription)
B. Binding and inhibition of NF kappa B
C. Inhibition of interleukin-1 gene transcription
D. Activation of calcineurin
E. Inhibition of interleukin-2 gene transcription
►E
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).
Dephosphorylated NFAT is active and causes the increase in IL2. Tacrolimus binds macrophillin1 which blocks calcineurin so NFAT is not dephosphorylated ie it remains phosphorylated and is inactive therefore preventing transcription of IL 2.
16 -This patient says the rash is spreading and not controlled with topical therapy. You give him a course of oral treatment that lasts:
A. 1 week
B. 2 weeks
C. 3 weeks
D. 4 weeks
E. 5 weeks
►C
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.
17 -Anti Jo-1 antibodies are directed against which of the following?
A. Topoisomerase
B. Lysyl oxidase
C. Gyrase
D. Histidyl transfer RNA synthetase
E. Telomerase
►D
Anti Jo-1 antibody is typical of autoimmune diseases that involve muscle, including dermatomyositis.
18 -Anti-epiligrin (laminin 5) antibodies may be seen in:
A. Pemphigoid gestationis
B. Pemphigus vegetans
C. Fogo selvagem
D. Cicatricial pemphigoid
E. Paraneoplastic pemphigus
►D
Patients with cicatricial pemphigoid have been reported to have anti-epiligrin antibodies.
19- Subacute cutaneous lupus erythematosus has been associated with the ingestion of which of the following drugs?
A. Phenytoin
B. Allopurinol
C. Terbinafine
D. Trimethoprim/sulfamethoxazole
E. Auranofin
►C
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.
20- This patient has a lichenified plaque in the lower mid abdomen as well as these two exczematous plaques. This patient needs:
A. Patch testing
B. A steroid
C. An antiviral
D. A KOH scraping
E. An antifungal
►A
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.
21- A previously healthy child presents with palpable purpura, arthritis, and vomiting. You suspect a hypersensitivity vasculitis characterized by:
A. Perivascular IgA
B. P-ANCA autoantibodies
C. Granulomas and eosinophilia
D. Infiltration of destruction of vessels by atypical lymphocytoid and plasmacytoid cells
E. Nectrotizing granulomatous vasculitis
►A
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.
22- Which immunoglobulin is most efficient at fixing complement?
A. IgM
B. IgE
C. IgD
D. IgA
E. IgG
►A
IgM is the first antibody produced by B cells. It is secreted by plasma cells as a pentamer. Due to its size, IgM doesn’t enter tissue well. It is the most efficient immunoglobin at fixing complement.
23 -Gene rearrangement analysis is useful for determining:
A. Lymphocyte clonality in MF
B. Lymphocyte activity
C. Gene Function
D. Gene Mutations
E. T cell receptor status
►A
Gene rearrangement studies are useful to detect clonality in antigen specific cell types (B cells, T cells).
24- Major histocompatibility complex class I molecules bind to:
A. Peptides derived from proteins synthesized and degraded in the cytosol
B. Peptides derived from proteins degraded in endocytic vesicles
C. Peptides external to the cell membrane
D. Immunoglobulin E
E. None of these answers are correct
►A
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.
25- The most definitive HLA association with psoriasis is:
A. HLA-Cw6
B. HLA-B27
C. HLA-B13
D. HLA-B17
E. HLA-B37
►A
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.
26- Immunocytomas are:
A. Low grade B-cell lymphomas
B. Aggressive B-cell lymphomas
C. Low grade T-cell lymphomas
D. Aggressive T-cell lymphomas
E. NK cell lymphomas
►A
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.
27 -Anti-Ro (SS-A) antibodies are most commonly found in:
A. Mixed connective tissue disease
B. Eosinophilic fasciitis
C. Drug-induced systemic lupus erythematosus
D. Homozygous C2 deficiency
E. Neonatal lupus erythematosus
►E
Ro 60 kDa autoantigen is a major target for patients with SLE and Sjogrenǁs 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.
28- Which of the following cytokines shifts the immune response towards TH2?
A. IL-4
B. IL-5
C. IL-10
D. TNF
E. IFN-gamma
►A
IL-4 is the cytokine that polarizes the immune response towards Th2. IL-5 is an eosinophil growth factor. IL-10 is a general down-regulator of 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.
29- Which of the follwing is a chemotactic factor for eosinophils?
A. TNF
B. IL2
C. C5a
D. Plasminogen activator
E. IL8
►C
Eosinophil chemotactic factors include all of the following: Histamine, soluble immune complexes, C5a, and HETE
30- Herpes simplex virus-related erythema multiforme has been associated with an increased frequency of:
A. HLA-B7
B. HLA-B8
C. HLA-B13
D. HLA-B15
E. HLA-B27
►D
Erythema multiforme associated with herpes simplex has been reported to have an increase of HLA-B15.
31- A homeless patient presents with a scaling, pustular periorifical eruption around the mouth and genitalia. What lab abnormality is associated with this condition?
A. Increased zinc level
B. Increased copper level
C. Decreased copper level
D. Decrease alkaline phosphatase level
E. Increased alkaline phosphatase level
►D
In a homeless patient with poor nutrition, acrodermatitis enteropathica due to zinc deficiency can presents with a scaling eruption of the periorificial regions. In addition to a low zinc level, levels of alkaline phosphatase, a zinc dependent enzyme, are decreased.
32- Which of the following immunoglobulins cannot activate the complement pathway?
A. IgM
B. IgG1
C. IgG2
D. IgG3
E. IgG4
►E
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.
33- Which of the following is an example of a delayed hypersensitivity reaction?
A. Allergic contact dermatitis
B. Anaphylaxis
C. Latex allergy
D. Transfusion reaction
E. Serum sickness
►A
There are 4 types of Hypersensitivities: (“ACID”) Type I: Anaphylactic and Atopic: Exampl es 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
34- This woman should have a workup for:
A. Lymphoma
B. Nephrolithiasis
C. Pancreatic cancer
D. Hemochromatosis
E. Thalassemia
►D
Porphyria cutanea tarda has been shown to be associated with hemochromatosis. Patients with hemochromatosis have mutations in the HFE gene, and early detection of mutations can improve life expectancy for these patients.
35- Langerhans cell adhesion to keratinocytes is mediated by what adhesion molecule?
A. E-cadherin
B. N-cadherin
C. Desmoglein 3
D. P-cadherin
E. B7
►A
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 cell s. Adhesion to keratinocytes in the epidermis is mediated by e-cadherin.
36- When attempting to identify Langerhans cells in a specimen, which marker is most helpful?
A. CD1
B. CD4
C. CD7
D. CD8
E. CD20
►A
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.
37- Elaboration of which of the following cytokines is characteristic of TH2 response?
A. Interferon-8 (gamma)
B. Interleukin-1
C. Interleukin-2
D. Interleukin-4
E. Interleukin-12
►D
Interleukin-4 (IL-4) is a cytokine involved in B-cell proliferation. Along with IL-5 and IL-13, IL4 is classified as a TH2 cytokine.
38- Which cytokine is most important in recruiting neutrophils?
A. Interleukin-1
B. Interleukin-2
C. Interleukin-4
D. Interleukin-8
E. Interleukin-10
►D
Chemotaxis is the process of cells moving through a gradient of towards increasingly higher concentrations. IL-8 has activating and chemoattractant properties on neutrophils.
39- Which monoclonal gammopathy is most commonly associated with erythema elevatum diutinum?
A. IgA
B. IgD
C. IgE
D. IgG
E. IgM
►A
A report of 13 patients indicated IgA is most commonly associated with EED.
40- Which cytokine is not upregulated in atopic dermatitis patients?
A. IL-13
B. IL-4
C. IL-5
D. IL-10
E. IFN-gamma
►E
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.
41- Dermatitis Herpetiformis is most commonly associated with which HLA?
A. HLA-DR3
B. HLA-B27
C. HLA-B8
D. HLA-Bw35
E. HLA-DQ(A10501, B102)
►E
HLA-DQ (A10501, B102) 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.
42- The most common autoimmune disorder in patients with chronic hepatitis C infection is:
A. Autoimmune thyroiditis
B. Idiopathic thrombocytopenic purpura
C. Rheumatoid arthritis
D. Sjӧgrenǁs syndrome
E. Systemic lupus erythematosus
►A
Autoimmune thrombocytopenia has been reported with hepatitis C infection but not as commonly as autoimmune thyroiditis.
43- 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?
A. B27
B. Cw6
C. B17
D. B51
E. B8
►A
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.
44- 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?
A. Sodium
B. Potassium
C. Calcium
D. Selenium
E. Zinc
►C
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.
45- Natural killer (NK) cells eliminate infected cells in all of the following ways except:
A. NK cells adhere to and kill target cells coated with IgG
B. NK cells secrete perforin
C. NK cells secrete granzyme
D. NK cells secrete myeloperoxidase
E. NK cells do not target cells expressing major histocompatibility (MHC) class I molecules
►D
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.
46- 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?
A. Acneiform eruption
B. Acral erythema
C. Morbilliform eruption
D. Hypotrichosis
E. Urticaria
►A
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.
47- Tacrolimus is a non-steroidal anti-inflammatory medication that works by inhibiting calcineurin activity through complexing with what binding protein?
A. FK506
B. TGF-beta
C. NF-kappa-B
D. SRE
E. IL-23
►A
Tacrolimus and pimecrolimus are non-steroidal calcineurin inhibitors that act as antiinflammatory 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.
48- Keratinocytes express what class of major histocompatibility complex under normal conditions?
A. MHC Class I
B. MHC Class II
C. MHC Class III
D. MHC Class IV
E. MHC Class V
►A
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.
49- Which component of the classical pathway of complement acts as an opsonin?
A. C3b
B. C3a
C. C5a
D. C5b
E. C1 INH
►A
“oBsonization”
The classical pathway of complement is activated by antigen-antibody complexes. C3a is a neutrophil chemoattractant. C3b is an opsonin. C5a is an anaphylatoxin. C5b forms a part of the membrane attack complex.
50- Which of the following immune-mediated events has been demonstrated in psoriasis vulgaris?
A. Clonal expansion of CD8+ T cells
B. Decrease dermal Langerhans cells
C. Downregulation of keratin 16
D. Increase Th2 CD4+ T cells
E. Decreased production of interferon-gamma
►A
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.
51- Which cytokine is responsible for fever in patients with sunburn?
A. IL-1
B. IL-5
C. IL-10
D. IL-11
E. TNF-beta
►A
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.
52- Which of the following substances is located in the core of an eosinophil?
A. Eosinophilic cationic protein
B. Eosinophil-derived neurotoxin
C. Eosinophil peroxidase
D. Major basic protein
E. Chymase
►D
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.
53 -Which paraprotein is found most commonly in patients with pyoderma gangrenosum?
A. IgG
B. IgA
C. IgM
D. IgE
E. IgD
►B
IgA paraproteinemia has been reported in over 10-18% of pyoderma gangrenosum.
54- Which of the following TH2 cytokines is a B cell growth factor?
A. IL-4
B. IL-5
C. IL-10
D. IL-13
E. IFN-gamma
►A
IL-4 is a B cell growth factor. IL-5 is an eosinophil growth factor. IL-10 is a general downregulator 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.
55- Which is not a feature of mast cells?
A. Expresses c-kit
B. Expresses CD-3
C. Produces IL-8
D. Produces prostaglandin D2
E. Stains with napththol chloro-acetate esterase
►B
Mast cells are an integral portion of immediate type hypersensitivity. CD3 is a T cell marker.
56 -Which of the following is associated with hepatitis C infection?
A. Essential mixed cryoglobulinemia
B. Rheumatoid arthritis
C. Relapsing polychondritis
D. Wegener‘s granulomatosis
E. Dermatomyositis
►A
Hepatitis C infections can present as urticaria or papable purpura and cryoglobulinemia.
57- All of the following stains can be reactive in this condition except
A. CDXIIIa
B. CD31
C. CD34
D. Ulex europaeus
E. Factor VIII-related antigen
►A
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.
58- Angiocentric NK/T-cell lymphoma in children may present as:
A. Papular acrodermatitis of childhood
B. Acropustulosis of infancy
C. Childhood dermatomyositis
D. Hydroa vacciniforme
E. En coup de sabre
►D
Hydroa vacciniforme a photodermatitis that typically occurs with sun exposure in the spring has been reported with NK/T cell lymphomas in childhood.
59- Histamine is a biologic amine produced by which of the following cells?
A. Monocytes
B. Eosinophils
C. Basophils
D. Platelets
E. Basophils and Platelets
►E
In the skin, histamine is mainly contained within the granules of dermal mast cells. Histamine is present in mast cells, basophils, and platelets.
60- The elicitation of nickel contact dermatitis requires signaling by which of the following?
A. TLR2
B. TLR4
C. LFA-1
D. TNF-alpha
E. IL-4
►B
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 lymphocytespecific 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.
61- Which of the following is the target antigen in pemphigus vulgaris?
A. Desmoglein 3
B. Desmoplakin
C. loricrin
D. Type XVII collagen
E. Desmoglein 1
►A
Desmoglein 3 is the dominant target auto-antigen in pemphigus vulgaris and is in the cadherin family.
62- Which cytokine is primarily responsible for stimulation of neutrophils?
A. IL-1
B. IL-4
C. IL-5
D. IL-6
E. IL-8
►E
IL-8 is primarily responsible for the stimulation of neutrophils. IL-5 stimulates eosinophils. IL-4 stimulates mast cells and IgE isotype switching
63- Which virus is most closely associated with Kaposiǁs sarcoma in HIV-infected patients?
A. Human herpes virus 2
B. Cytomegalovirus
C. Human herpes virus 6
D. Human herpes virus 8
E. Epstein-Barr virus
►D
HHV-8 has been repeatedly associated with all forms of Kaposiǁs sarcoma.
64- Which component of the T cell receptor is associated with superantigen recognition?
A. D-beta
B. J-alpha
C. J-beta
D. V-alpha
E. V-beta
►E
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.
65- Which of the following cytokines is primarily involved in activating eosinophils?
A. IL-5
B. TNF-alpha
C. IL-10
D. IL-2
E. Interferon-gamma
►A
Eosinophils provide many functions of the immune system, including protection against helminths. They are activated by IL-5.
66 -Relapsing polychondritis is an autoimmune disease associated with immunity to which type of collagen?
A. I
B. II
C. III
D. IV
E. VII
►B
Relapsing polychondritis has been reported to have autoantibodies to type II collagen.
67- A deficiency of this complement component may result clinically in susceptibility to pyogenic infections, glomerulonephritis, and partial lipodystrophy:
A. C1 Esterase Inhibitor
B. C3
C. C4
D. C50
E. Properidin
►B
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.
68- Which of the following cytokines, together with IL-4, promotes isotype switching from IgM to IgE?
A. IL-5
B. IL-10
C. IL-13
D. TNF
E. IFN-gamma
►C
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. IFN-gamma is secreted by TH1 cells, and is the main macrophage-activating cytokine.
69- 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:
A. Parvovirus B19
B. Herpes simplex virus
C. Coxsackievirus
D. Cytomegalovirus
E. Human immunodeficiency virus
►B
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.
71 -This skin disease has been shown to be associated with reduced Beta 2 defensin. The diagnosis is:
A. Atopic dermatitis
B. Psoriasis
C. Lepromatous leprosy
D. Tuberculoid leprosy
E. Subacute cutaneous lupus erythematosus
►A
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.
110- 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:
A. Ginkgo fruit
B. Croton
C. Ragweed
D. Tea tree oil
E. All of these answers are correct
►A
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.
173 -The human major histocompatibility complex (MHC) is located on chromosome:
A. 2
B. 6
C. 9
D. 11
E. 17
►B
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.
