Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NBME Micro > Immunology: Immune Responses > Flashcards

Immunology: Immune Responses Flashcards

1
Q

Which 3 cytokines secreted by macrophages may contribute to the development of fever and sepsis?

A

Interleukin-1, interleukin-6, tumor necrosis factor-α

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the definition of an anergic state?

A

It is an inactive state in which an immune cell cannot become activated when exposed to a specific antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does Epstein-Barr virus invade B cells to cause infectious mononucleosis?

A

EBV binds to CD21on the surface of B cells (must be 21 to drink Beer in a Barr)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Myasthenia gravis, Graves disease, and pemphigus vulgaris are examples of what type II hypersensitivity mechanism?

A

Cellular dysfunction, in which the opsonized cells do not function normally but are not completely destroyed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A patient is diagnosed with a hereditary deficiency of the enzyme involved in the regeneration of NADPH from NADP+. Which enzyme is deficient?

A

Glucose-6-phosphate dehydrogenase (G6PD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What steps in antibody generation are antigen independent or antigen dependent?

A

Generation of antibody diversity is antigen independent; generation of antibody specificity is antigen dependent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When a cell is opsonized (coated) by antibodies in a type II hypersensitivity reaction, what are the cell’s 2 potential fates?

A

Phagocytosis and/or complement system activation or destruction by natural killer cells (antibody-dependent cellular cytotoxicity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Iron is an essential nutrient for microbes. What protein found in secretory fluids and neutrophils counteracts microbes via iron chelation?

A

Lactoferrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does a live attenuated vaccine contain?

A

A microorganism that has been modified to lose its pathogenicity (though it retains the capacity for transient growth within the host)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What lab findings are associated with hyper-IgE syndrome (Job syndrome)?

A

Increased IgE levels and eosinophilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the pathophysiology of leukocyte adhesion deficiency type 1?

A

Lack of LFA-1 integrin (CD18) on phagocytes → impaired migration and chemotaxis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Type IV hypersensitivity reactions can occur by 2 mechanisms. Describe the inflammatory reaction mechanism

A

Effector CD4+ T cells detect antigen and release cytokines that induce inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A patient experiences severe graft dysfunction within minutes of kidney transplantation. What is the correct treatment?

A

Removal of the graft (the appropriate treatment for a patient with hyperacute rejection, which occurs within minutes of transplantation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The Arthus reaction is what type of hypersensitivity reaction?

A

Type III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is the lectin pathway of the complement system activated?

A

Mannose or other sugars found on microbial surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name the 2 autoantibodies associated with pernicious anemia.

A

Antiparietal cell and anti-intrinsic factor autoantibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the main drawback associated with toxoid vaccines?

A

They stimulate the production of antitoxin levels that decrease with time (requiring subsequent boosters)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

An hour after blood transfusion, a patient reports fever, dyspnea, flank pain, and jaundice. What is the diagnosis?

A

Acute hemolytic transfusion reaction (type II hypersensitivity); antibodies to donor RBC surface antigens cause extravascular hemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the mechanism by which type II hypersensitivity causes inflammation.

A

Binding of antibodies to cell surfaces leads to complement system activation and Fc receptor–mediated inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

A patient with IgA deficiency develops wheezing, hypotension, and respiratory arrest after receiving a blood transfusion. What is the most likely cause?

A

Type I hypersensitivity reaction to IgA in donor blood; patients with IgA deficiency must receive blood products that do not contain IgA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

A patient with cancer appears thin with prominent temporal muscle wasting. Which cytokine is known to promote this process?

A

Tumor necrosis factor-α (promotes cachexia in malignancy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Mast cells play a major role in immediate, type I hypersensitivity. Which antibody isotype facilitates this phenomenon?

A

IgE (cross-links when exposed to an allergen and mediates the release of inflammatory mediators)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which type of cells produce and secrete interferons?

A

Virally infected cells (interferons interfere with viruses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the 5 major adverse effects shared by interferons when used in pharmacotherapy?

A

Myopathy, neutropenia, flu-like symptoms, depression, and autoimmune reactions (interferon-induced autoimmunity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How might a 2-month-old child receive passive immunity from her mother outside of the womb?

A

Via breastfeeding (breast milk contains maternal IgA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the inheritance pattern for ATM gene mutations causing ataxia-telangiectasia?

A

Autosomal recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Name the 2 proteins that prevent complement activation on self cells.

A

Decay-accelerating factor (DAF), also known as CD55, and C1 esterase inhibitor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

IgA is secreted in its dimeric form with an associated J chain. In which bodily secretions is the antibody found?

A

Tears, saliva, mucus, and breast milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What test is used to assess for contact dermatitis?

A

Patch test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Which type of hypersensitivity is involved in transplant rejections?

A

Types II and IV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the 3 main functions of interleukin-5?

A

Stimulates growth and differentiation of eosinophils, promotes B-cell growth and differentiation, enhances class switching to IgA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Which type of immune cell secretes TNF-α?

A

Macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Which antibody isotype is the most abundant in serum?

A

IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

A 4-year-old girl is diagnosed with common variable immunodeficiency. What type of poliovirus vaccine may be contraindicated?

A

The Sabin oral vaccine (live, attenuated polio vaccines are contraindicated for patients with B-cell deficiencies)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Name the autoantibodies associated with dermatomyositis and polymyositis.

A

Antisynthetase (eg, anti-Jo-1), anti-SRP, and anti-helicase (anti-Mi-2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What test is used to determine T-cell immune function, via a type IV hypersensitivity-mediated reaction?

A

Candida skin test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

A patient presents with dark urine, a low haptoglobin level, and lysed RBCs on blood smear due to a defect in the complement system. What is the diagnosis?

A

Paroxysmal nocturnal hemoglobinuria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are 2 key examples of bacterial toxoid vaccines?

A

Corynebacterium diphtheriae (diphtheria toxoid) and Clostridium tetani (tetanus toxoid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Chronic granulomatous disease can be treated with which glycoprotein-based therapy?

A

Interferons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Rheumatoid factor, often positive in rheumatoid arthritis, is an autoantibody targeting which immunoglobulin?

A

It is an IgM antibody against the Fc region of IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the common causes of serum sickness-like reactions?

A

Drugs such as penicillin (acting as haptens) and infections such as hepatitis B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

A 55-year-old patient receives a Td (tetanus and diphtheria) booster vaccine. He received all of his childhood vaccines. Why is this booster necessary?

A

The vaccines against Clostridium tetani and Corynebacterium diphtheriae are toxoids, which are associated with decreasing antitoxin (antibody) levels over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the purpose of anergy in regulating acquired immunity?

A

To promote self-tolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

When does intravascular hemolysis occur in acute hemolytic transfusion reactions?

A

When ABO blood group incompatibility exists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Describe the lectin pathway all the way to C5 cleaving into C5a/b.

A

C1-like complex cleaves C4 into C4a/C4b → C4b + C2b → C4b2b (C3 convertase) cleaves C3 into C3a/C3b → C4b2b3b (C5 convertase) cleaves C5 into C5a/C5b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Which 2 viral infections are commonly treated with interferons?

A

Chronic HBV and HCV infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

A patient with leukemia receives a bone marrow transplant and develops graft-versus-host disease. How is this a potentially desirable effect?

A

This may be beneficial in the eradication of leukemia cells (the “graft-versus-tumor” effect)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

The hinge region of an antibody connects which 2 domains?

A

The Fab region of the heavy chain and the Fc region; specifically, CH1 and CH2 domains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Anti-glomerular basement membrane autoantibodies are associated with which disorder?

A

Goodpasture syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

A boy has thrombocytopenia, eczema, and recurrent pyogenic infections. What conditions is this patient increased risk for?

A

Malignancy and autoimmune diseases (he has Wiskott-Aldrich syndrome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

A woman receives a bone marrow transplant. Afterward, detection of which cell surface protein indicates a successful procedure?

A

CD34 (indicative of hematopoietic stem cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Name the disease that is implicated with defects in anchoring of complement inhibitors, such as decay-acclerating factor (DAF/CD55) and MIRL/CD59.

A

Paroxysmal nocturnal hemoglobinuria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Which 4 types of HPV does the standard quadrivalent subunit HPV vaccine protect against?

A

Types 6, 11, 16, and 18

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is a common histologic manifestation of chronic rejection of a liver transplant?

A

Vanishing bile duct syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is the enzyme that catalyzes the conversion of oxygen (O2) to superoxide (O2-•) in the first step of respiratory burst?

A

NADPH oxidase (converts O2 into O2-• via the conversion of NADPH into NADP+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

A patient has fever, joint pain, lymphadenopathy, hives, and proteinuria. He began taking a new drug 7 days ago. What is the diagnosis?

A

Serum sickness (type III hypersensitivity reaction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Which antibody isotype acts as the main antibody in the secondary, delayed response to an antigen?

A

IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Which molecular cofactor is required for both the creation and neutralization of reactive oxygen species (ROS)?

A

NADPH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What are the 3 main functions of tumor necrosis factor-α?

A

Activation of endothelium, recruitment of WBCs, promotion of vascular leak

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Aside from a bone marrow transplant, what other treatment measures are important for patients with severe combined immunodeficiency (SCID)?

A

Antimicrobial prophylaxis, administration of IVIG, and avoidance of live vaccines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

A pregnant patient asks about receiving the MMR vaccine. Why would you avoid giving her this vaccine?

A

Because MMR is a live attenuated vaccine, the microorganism may revert to a virulent form (and is therefore contraindicated in pregnancy and immunodeficiency)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

B cells undergo gene rearrangement and differentiate into plasma cells. As plasma cells, which immunoglobulin (Ig) isotypes will they be able to secrete?

A

IgA, IgG, or IgE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What are the 4 types of hypersensitivity reactions?

A

Anaphylactic and Atopic (type I), antiBody-mediated (type II), immune Complex (type III), and Delayed (type IV, cell-mediated) (ABCD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What Ig isotype most commonly forms the immune complexes implicated in type III hypersensitivity reactions?

A

IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

A patient has a rash on her cheeks, arthralgias, and antibodies to ANA and dsDNA. What type of hypersensitivity reaction causes this disease?

A

Type III (the patient has SLE)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Thymic aplasia results from a failure in the development of what pharyngeal pouches?

A

3rd and 4th pharyngeal pouches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

A defect in what gene prevents anchoring of complement inhibitors in paroxysmal nocturnal hemoglobinuria?

A

PIGA Gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

A patient receiving treatment with IFN-α for renal cell carcinoma develops symmetric pain and stiffness of the PIP and MCP joints. What has likely occurred?

A

Interferon-induced autoimmunity has likely developed (manifesting similarly to rheumatoid arthritis in this case)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Describe the mechanism of the immediate phase of a type I hypersensitivity reaction.

A

Antigen crosslinks IgE on the surface of presensitized mast cells → immediate degranulation → release of histamine and tryptase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Which type of immune cell secretes interleukin-1?

A

Macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

IgA crosses epithelial cells by transcytosis. In which structural form is IgA secreted?

A

Dimeric form, with J chain (monomeric form only found in serum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is the classic triad of presentation seen in ataxia telangiectasia?

A

Ataxia, spider Angiomas, decreased IgA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

A patient with fevers and a new heart murmur is found to have tricuspid endocarditis. Blood cultures grow yeasts with pseudohyphae. What immune cell count may be reduced?

A

Granulocytes may be deficient (increasing the risk of systemic or bloodstream candidal infections)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

A patient is diagnosed with X-linked agammaglobulinemia. To what type of recurrent bacterial infection is he most susceptible?

A

Encapsulated (Please SHINE my SKiS: Pseudomonas, Streptococcus pneumoniae, H Influenzae type b, N meningitidis, E coli, Salmonella, Klebsiella, group B Streptococcus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

In what part of the phagocyte does respiratory (oxidative) burst occur?

A

The phagolysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What are the 2 key disadvantages of subunit vaccines?

A

They are expensive and induce a weaker immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Inactivated or killed vaccines are often safer but weaker than their live attenuated counterparts. What type of active immune response is triggered?

A

A humoral response only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What are the 4 main functions of interleukin-1?

A

Induces fever and acute inflammation, activates endothelium to express adhesion molecules, induces chemokine secretion to recruit WBCs, activates osteoclasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What 3 immunoglobulin isotypes are typically decreased in patients with ataxia-telangiectasia?

A

IgA, IgG, and IgE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What response can the cytokines interleukin-1, interleukin-6, and tumor necrosis factor-α all cause?

A

Fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

How is a killed vaccine prepared?

A

The pathogen is inactivated with heat or chemicals before administration (leaving the epitope structure on surface antigens intact)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Which class of medication is contraindicated for patients with C1 esterase inhibitor deficiency?

A

ACE inhibitors because they also increase bradykinin levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Combined active and passive immunization should be given when exposure to what 2 diseases is suspected?

A

Hepatitis B virus, rabies virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

A patient presents with swelling and pain in her PIP and MCP joints, bilaterally. Of the autoantibodies associated with this condition, which are more specific?

A

Anti-CCP autoantibodies (this is rheumatoid arthritis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What 2 stimuli are required for NK cells and T cells to secrete interferon-γ?

A

Exposure to antigens, exposure to interleukin-12 from macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

What are 10 key examples of live vaccines?

A

Adenovirus/Typhoid/Polio/Varicella/Smallpox/BCG/Yellow fever/Influenza/MMR/Rotavirus (Attention Teachers! Please Vaccinate Small, Beautiful Young Infants with MMR Regularly) was

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

A patient agrees to receive the annual injected influenza vaccine. What is the main drawback of this type of vaccination?

A

Because it is an inactivated vaccine, the immune response is weaker (booster shots or repeated vaccinations are often required)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Name the 2 complexes that can act as C5 convertase in the complement system.

A

C3bBb3b (from alternative pathway) and C4b2b3b (from classical/ lectin pathway); both act to cleave C5 into C5a and C5b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Which immunodeficiency syndrome is commonly treated with interferons?

A

Chronic granulomatous disease (CGD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

What is the most common cause of hyper-IgM syndrome?

A

Defective CD40L on T helper (Th) cells, which is necessary for B-cell class switching

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

What is the main advantage associated with the administration of a live attenuated vaccine?

A

Strong, often lifelong immunity is produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

In the generation of antibody diversity, nucleotides are added randomly to DNA during recombination. What enzyme performs this action?

A

Terminal deoxynucleotidyl transferase (TdT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

An immunoglobulin is released in breast milk and does not fix complement. Name this immunoglobulin isotype.

A

IgA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What is serum sickness?

A

An immune complex disease; antibodies to foreign proteins are made and deposited in tissues, where they fix complement and cause damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

What autoantibodies are associated with diffuse scleroderma?

A

Anti-Scl-70 (anti-DNA topoisomerase I [Scleroderma])

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

The bacterial catalase enzyme converts H2O2 generated from oxidative burst into what 2 products?

A

Water, oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

What is the mechanism of the hypersensitivity reaction involved in polyarteritis nodosa?

A

In type III hypersensitivity, antigen-antibody complexes activate complement, leading to neutrophil chemotaxis and immune complex deposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

What is the genetic inheritance of IL-12 receptor deficiency?

A

Autosomal recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

A boy has recurrent Staphylococcus aureus, Escherichia coli, and Aspergillus infections. Which 2 tests confirm the diagnosis?

A

Negative nitroblue tetrazolium and abnormal (↓ green fluorescence) dihydrorhodamine test results (diagnosis: chronic granulomatous disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

Which disease is associated with antimitochondrial autoantibodies?

A

Primary biliary cholangitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

MPO-ANCA/p-ANCA autoantibodies are associated with which 3 disorders?

A

Microscopic polyangiitis, Churg-Strauss syndrome (eosinophilic granulomatosis with polyangiitis), and ulcerative colitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

Patients with ataxia-telangiectasia are at increased risk for which malignancies?

A

Lymphomas and leukemias

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

Patients with DiGeorge syndrome are susceptible to what type of infections?

A

Viral and fungal (due to absence of T cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

A patient with pancytopenia who is undergoing marrow chemoablation in preparation for bone marrow transplantation requires blood products. What must be done before transfusion?

A

The blood products must be irradiated (as this helps prevent GVHD in immunocompromised patients)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

How does the humoral type of acute rejection differ from hyperacute rejection in its pathophysiology?

A

Antibodies against graft donor antigen(s) develop after transplantation in acute rejection (vs pre-existing antibodies in hyperacute rejection)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

What characteristic findings are seen in chronic mucocutaneous candidiasis?

A

Lack of cutaneous reaction to Candida antigens and absence of in vitro T-cell proliferation in response to Candida antigens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

What medical measure is contraindicated in patients with X-linked (Bruton) agammaglobulinemia?

A

Live vaccines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

A new mother expresses concern that her baby will have a “bad reaction” to the Hib (Haemophilus influenzae type b) vaccine. What is the correct response?

A

The chance of an adverse reaction to a subunit vaccine (eg, Hib) is extremely low, even relative to other vaccine types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

Besides typical T-cell surface proteins (TCR, CD3, CD28), which cell surface proteins do regulatory T cells have?

A

CD4 and CD25

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

Membrane attack complex (MAC) is important for protection against what type of organisms?

A

Gram-negative bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

Why are patients with chronic granulomatous disease (CGD) susceptible to catalase-positive organisms?

A

Catalase-positive species can neutralize their own H2O2, leaving the phagocytes of patients with CGD incapable of producing ROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

The interferon response is classified as a component of what branch of the immune system?

A

The innate response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

What is the temporal onset and duration of passive immunity?

A

Rapid onset but short duration of antibody protection (half-life of 3 wk)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

Which HBV antigen does the recombinant subunit HBV vaccine contain?

A

HBsAg (which is why vaccinated patients are typically positive for the anti-HBs antibody)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

What are the 3 mechanisms of a type II hypersensitivity reaction?

A

Opsonization/phagocytosis, complement- and Fc receptor–mediated inflammation, antibody-mediated cell dysfunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

To what specific region(s) of the heavy chain do macrophages bind?

A

CH2 and CH3 regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

What conditions might be seen in patients with common variable immunodeficiency?

A

Autoimmune diseases, bronchiectasis, lymphoma, sinopulmonary infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

Anti-U1 RNP (ribonucleoprotein) autoantibodies are associated with which disorder?

A

Mixed connective tissue disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

Name the 3 autoantibodies associated with celiac disease.

A

IgA and IgG deamidated gliadin peptide, IgA anti-endomysial, IgA anti-tissue transglutaminase autoantibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

Which disorder is associated with autoantibodies against the presynaptic voltage-gated calcium channel?

A

Lambert-Eaton myasthenic syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

What effect can a T-cell deficiency have on a bacterial infection?

A

Increased risk of sepsis (due to rapid dissemination of the infection)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

How rapidly does chronic transplant rejection develop?

A

Within months to years of transplantation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

The umbilical cord fails to separate within 30 days in a neonate. Neutrophilia is noted on labs. What is the diagnosis?

A

Leukocyte adhesion deficiency type 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

Describe the mechanism of serum sickness.

A

Antibodies to foreign proteins are produced; 1–2 wk later, antibody-antigen complexes are formed and deposited in tissue → complement activation → inflammation/tissue damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

After exposure to which 6 agents may preformed antibodies be administered (as a part of postexposure prophylaxis)?

A

Tetanus toxin, Botulinum toxin, HBV, Varicella, Rabies virus, or Diphtheria toxin (“To Be Healed Very Rapidly before Dying”)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

Anti-dsDNA and anti-Smith autoantibodies are associated with which disorder?

A

Systemic lupus erythematosus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

What triad of symptoms are seen in Wiskott-Aldrich?

A

Wiskott-Aldrich: Thrombocytopenia, Eczema, Recurrent (pyogenic) infections (WATER)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

A patient receiving induction chemotherapy for acute leukemia has severe granulocytopenia. To what types of microbes is she most susceptible

A

Bacteria (Some Bacteria Produce No Serious granules: Staphylococcus, Burkholderia, Pseudomonas, Nocardia, Serratia) and fungi (systemic Candida, Aspergillus, Mucor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

The phagocytes of patients with chronic granulomatous disease (CGD) can still make ROS from what compound provided by invading organisms?

A

H2O2 (however, catalase-positive organisms can neutralize their own H2O2, thus circumventing this mechanism)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

How is the classic pathway activated?

A

By IgG or IgM mediated antigen-antibody complexes (GM makes classic cars)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

What enzyme is responsible for the incorporation of chloride into hydrogen peroxide to form hypochlorite radicals?

A

Myeloperoxidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

Which cell surface receptors does the human immunodeficiency virus use to infect its target host cells?

A

HIV binds to CD4 and either CXCR4 or CCR5, which serve as co-receptors, on T helper cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

What is the general difference between infections commonly associated with T-cell and B-cell deficiencies?

A

T-cell deficiencies tend to produce recurrent viral/fungal infections, while B-cell deficiencies tend to produce recurrent bacterial infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
134
Q

Why do cells like neutrophils and monocytes have high concentrations of NADPH oxidase?

A

To aid in the immune response by rapidly releasing reactive oxygen species (ROS) that kill bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
135
Q

A patient develops hives, tongue swelling, and difficulty breathing after eating peanuts. Which complement proteins are responsible for these symptoms?

A

C3a, C4a, C5a—anaphylaxis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
136
Q

What general type of vaccine includes only the antigens that best elicit an immune response?

A

Subunit vaccines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
137
Q

Why are thymus-independent antigens weakly immunogenic or entirely nonimmunogenic?

A

They lack a peptide component; therefore MHC-mediated presentation to T cells cannot occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
138
Q

How can acute transplant rejection be prevented or reversed?

A

With the use of immunosuppressants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
139
Q

Describe the levels of immunoglobulins that characterize selective IgA deficiency.

A

Decreased IgA level with normal IgG and IgM levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
140
Q

How is the alternative pathway of the complement system activated?

A

By microbial surface molecules and spontaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
141
Q

What radiographic finding is associated with DiGeorge syndrome?

A

Lack of thymic shadow on chest x-ray

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
142
Q

What is unique about the type IV hypersensitivity reaction as compared with the other types?

A

The response is delayed and it does not involve antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
143
Q

A patient with HIV infection has a CD4 count of 600 cells/mm3. What are the 2 live attenuated vaccines that can be given to this patient?

A

MMR and varicella vaccines can be given to HIV+ patients with a CD4 cell count ≥ 200 cells/mm3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
144
Q

What are the 2 primary functions of C3b?

A

Opsonization and clearance of immune complexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
145
Q

Which immunodeficiency is due to a defect in B-cell differentiation resulting in decreased plasma cell levels?

A

Common variable immunodeficiency (CVID)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
146
Q

Live attenuated vaccines often induce strong, lifelong immunity. What 2 types of active immune responses are triggered?

A

Cellular and humoral responses

147
Q

A newborn with B+ blood born to an O+ mother develops jaundice and hepatomegaly 24 hr after birth. What is the mechanism of the disease?

A

Type II hypersensitivity reaction (the infant has hemolytic disease of the newborn)

148
Q

Years after a kidney transplant, a patient develops chronic graft glomerulopathy. What is the mechanism of this rejection?

A

CD4+ T cells and antibodies react against donor antigens, including allogeneic MHCs (as this is a kidney-specific form of chronic rejection)

149
Q

What enzyme catalyzes the conversion of superoxide into hydrogen peroxide in the second step of respiratory burst?

A

Superoxide dismutase (converts superoxide into hydrogen peroxide, H2O2)

150
Q

What cardiac defects are typically associated with DiGeorge syndrome?

A

Conotruncal abnormalities (tetralogy of Fallot, truncus arterious, etc)

151
Q

A 5-year-old boy has history of recurrent viral illnesses, truncus arteriosus, and tetany. What genetic defect is the cause of the condition?

A

22q11 microdeletion (he has DiGeorge syndrome)

152
Q

What benefit is conferred by IgM assuming a pentameric configuration?

A

Increased ability to trap free antigens out of tissue while the humoral response is evolving

153
Q

What is the most common primary immunodeficiency?

A

Selective IgA deficiency

154
Q

What are 6 key examples of subunit vaccines?

A

HBV (antigen is HBsAg), HPV (types 6, 11, 16, 18), acellular pertussis (aP), Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b

155
Q

A transplant recipient has a maculopapular rash, jaundice, hepatosplenomegaly, and diarrhea. She probably received 1 of which 2 types of transplants?

A

Bone marrow or liver (lymphocyte-rich tissues, which may predispose to graft-versus-host disease)

156
Q

What are 2 cells that utilize the phagocyte NADPH oxidase complex?

A

Neutrophils, monocytes

157
Q

How does IgA protect itself from breakdown by luminal proteases?

A

It picks up a secretory component from epithelial cells, thereby shielding its Fc portion from proteases

158
Q

What unique chemical bond is found within the hinge region of an antibody molecule?

A

Disulfide (S-S) bond

159
Q

What general type of vaccine is composed of a denatured bacterial toxin with an intact receptor binding site?

A

Toxoid vaccines

160
Q

What types of infections are commonly seen in X-linked (Bruton) agammaglobulinemia?

A

Recurrent bacterial and enteroviral infections

161
Q

What autoantibodies are associated with limited scleroderma/CREST syndrome?

A

Anticentromere antibodies

162
Q

What are the 2 main functions of interleukin-6?

A

Induces fever and stimulates production of acute-phase proteins

163
Q

What cytokine from Th2 cells enhances class switching to IgE and IgG?

A

Interleukin-4

164
Q

What 2 cytokines are secreted by all T cells?

A

Interleukin-2 and interleukin-3

165
Q

Which complement disorder causes recurrent Neisseria bacteremia?

A

Terminal complement (C5–C9) deficiencies

166
Q

A CXR obtained from a patient with hypoxemia has a diffuse ground-glass appearance. This patient is likely to have a deficiency of what type of immune cell?

A

T cells (this is Pneumocystis jiroveci pneumonia, or PCP, a fungal infection common in T-cell–immunodeficient states)

167
Q

Which 3 cell surface proteins are common to all T cells?

A

TCR, CD3, and CD28

168
Q

What are 5 key examples of inactivated or killed vaccines?

A

Rabies, Influenza (injected), Polio (SalK = Killed), hepatitis A, typhoid (Vi polysaccharide, intramuscular) (RIP Always)

169
Q

Which form of glutathione must be readily available in the cell to remove reactive oxygen species to prevent cell lysis?

A

The reduced form (GSH); recall that reducing equivalents are created in the HMP shunt

170
Q

After a camping trip, a patient presents with an itchy, red, oozing rash on the lower extremities, sparing the area under his socks. What is the diagnosis?

A

Contact dermatitis (type IV hypersensitivity): sensitized T cells encounter antigen and release cytokines, causing macrophage activation

171
Q

What are the 4 main functions of interferon-γ?

A

Triggers macrophages to kill phagocytosed pathogens, induces NK cells to kill virus-infected cells, increases MHC expression by all cells, inhibits differentiation of Th2 cells

172
Q

What are the 3 main functions of interleukin-10?

A

Attenuates inflammation, decreases MHC class II and Th1 cytokine expression, inhibits active macrophages/dendritic cells (APCs)

173
Q

A booster shot for the pneumococcal vaccine, PPSV23, is recommended for patients over 65. Does the antigen have a peptide component?

A

No; the vaccine contains a thymus-independent antigen, which lacks a peptide component

174
Q

Name 4 inherited immunodeficiencies that X-linked recessive, and thus are more common in boys.

A

Hyper-IgM syndrome, Wiskott-Aldrich syndrome, chronic granulomatous disease, Bruton agammaglobulinemia (and some types of severe combined immunodeficiency)

175
Q

Which type of immune cell secretes interleukin-12?

A

Macrophages

176
Q

Which disease is associated with anti-hemidesmosome autoantibodies?

A

Bullous pemphigoid

177
Q

What component on the bacterial surface does C3b bind to in order to opsonize the pathogen?

A

Lipopolysaccharides

178
Q

DiGeorge syndrome, IL-12 receptor deficiency, Job syndrome, and chronic mucocutaneous candidiasis feature dysfunction of which cell type?

A

T Cells

179
Q

What can be observed on flow cytometry and lymph node biopsy from a patient with severe combined immunodeficiency?

A

Lack of T cells on flow cytometry and no germinal centers in lymph nodes

180
Q

A man comes to the clinic with a disseminated mycobacterial infection after receiving the BCG vaccine. He has low IFN-γ levels. Which leukocytes are affected in this patient?

A

Th1 cells (he has IL-12 receptor deficiency)

181
Q

Name the organ responsible for synthesis of complement proteins.

A

Liver

182
Q

A child develops fever, headache, flushing, and chills 4 hours after receiving a blood transfusion. How could this be prevented in the future?

A

By using leukoreduced blood products (this is febrile nonhemolytic transfusion reaction)

183
Q

What mechanism within the oxidative burst process triggers the release of lysosomal enzymes?

A

K+ influx, which is triggered by oxidative burst

184
Q

Starting with C1, trace the classic complement pathway all the way to the cleavage of C5 to C5a/b.

A

C1 cleaves C2 into C2a/C2b → C2b + C4b → C4b2b (C3 convertase) cleaves C3 into C3a/C3b → C4b2b3b (C5 convertase) cleaves C5 into C5a/C5b

185
Q

Each B cell produces an immunoglobulin specific to 1 antigen. How is antibody diversity established?

A

1) Random recombination of VJ and V(D)J genes; 2) insertion of random nucleotides into DNA by TdT; 3) random combination of light and heavy chains

186
Q

What is the pathogenetic mechanism whereby hyperacute rejection develops?

A

Pre-existing recipient antibodies react to donor antigens (type II hypersensitivity), causing thrombosis of graft vessels and necrosis

187
Q

Which antibody isotype has the lowest serum concentrations?

A

IgE

188
Q

Which receptor found on natural killer cells binds to the Fc region of IgG?

A

CD16

189
Q

One mechanism of febrile nonhemolytic transfusion reactions is a type II hypersensitivity reaction. What is the other mechanism?

A

Cytokines that are created and accumulate in the storage of blood products can also incite the transfusion reaction

190
Q

A woman has ataxia, weblike angiomas, low IgA levels, high AFP, and cerebellar atrophy on imaging. Which gene is defective?

A

The ATM gene: ataxia-telangiectasia is due to ATM gene defects encoding DNA repair enzymes

191
Q

A patient with longstanding severe rheumatoid arthritis is diagnosed with osteoporosis. Which cytokine may have mediated the development of this condition?

A

IL-1, which may have been upregulated by chronic inflammation; IL-1 causes activation of osteoclasts, which can increase bone resorption

192
Q

A young child has no B cells in peripheral blood, low immunoglobulins, and scanty tonsils. What is the diagnosis?

A

X-linked (Bruton) agammaglobulinemia

193
Q

What is the pathogenesis of chronic granulomatous disease?

A

Defective NADPH oxidase → ↓ ROS and oxidative burst → ↑ susceptibility to catalase ⊕ organisms

194
Q

A patient is diagnosed with C9 complement deficiency. Which vaccine must be given immediately?

A

The meningococcal vaccine to Neisseria meningitidis, as there is no formation of membrane attack complex in late complement deficiencies

195
Q

What gene is affected in patients with Wiskott-Aldrich syndrome?

A

WAS gene

196
Q

What are the 2 possible causes of severe combined immunodeficiency (SCID) and their respective modes of inheritance?

A

Adenosine deaminase deficiency (autosomal recessive) and defective IL-2R gamma chain (X-linked recessive)

197
Q

Which cell surface proteins are found on macrophages?

A

CD14, CD40, CCR5, MHC II, B7 (CD80/86), and receptors for Fc and C3b

198
Q

A young patient is found to have an absence of B cells. To which types of viruses is he most susceptible?

A

Enteroviruses including poliovirus (especially manifesting as enteroviral encephalitis)

199
Q

IgM can be found as a monomeric surface receptor on B cells. In which structural form is it secreted?

A

Pentameric form, with associated J chains

200
Q

What cell surface protein found on macrophages acts as a receptor for PAMPs, such as LPS?

A

CD14

201
Q

Which 2 cell surface proteins are suggestive of NK cell lineage?

A

CD16 and CD56

202
Q

Why does X-linked (Bruton) agammaglobulinemia usually manifest after the age of 6 months?

A

Maternal-derived IgG protects the infant against infections; those levels begin to wane at 6 months after birth

203
Q

Thymus-dependent antigens are often strongly immunogenic as they contain a peptide component. Which 2 immunologic phenomena do they cause?

A

Class switching and immunologic memory formation due to interaction of B cells and Th cells

204
Q

How do the Fab and Fc regions determine the type of antibody that will be produced?

A

Fab determines the idiotype (a binding pocket specific to antigen); Fc determines the isotype (IgM, IgA, etc)

205
Q

Which immunoglobulin isotype is produced in the primary, immediate response to an antigen?

A

IgM

206
Q

Individuals with selective IgA deficiency have an increased risk for infection by what specific pathogen?

A

Giardia species

207
Q

Name the 2 molecules that act as opsonins to defend against bacterial infections.

A

C3b and IgG

208
Q

A patient has recurrent fungal infections of the skin and mucous membranes due to a defect in the AIRE gene. Name the disease.

A

Chronic mucocutaneous candidiasis

209
Q

A patient with sepsis is found to have elevated levels of ferritin, fibrinogen, and C-reactive protein. Which cytokine may account for this finding?

A

Interleukin-6 (which stimulates the production of acute-phase proteins)

210
Q

Describe the mechanism by which type II hypersensitivity causes cellular dysfunction.

A

Binding of antibodies to cell surface receptors leads to abnormal blockade or activation of downstream processes

211
Q

A child develops wheezing and hives after consuming peanuts. How would you test for the responsible hypersensitivity reaction?

A

Use a skin test or blood test (ELISA) for allergen-specific IgE in a type I hypersensitivity reaction

212
Q

Patients with chronic granulomatous disease (CGD) experience recurrent infections with catalase-positive organisms. What enzyme is deficient?

A

NADPH oxidase (for example, Staphylococcus aureus and Aspergillus are common catalase-positive species seen in patients with CGD)

213
Q

A boy develops hives when he eats a peanut butter sandwich. The activation of which 2 cell types is most likely to blame?

A

Mast cells and basophils due to IgE activation and cross-linking

214
Q

Interferons are effective in the immune response to which pathogen: bacteria, virus, fungus, or parasite?

A

Viruses (both RNA and DNA)

215
Q

What 5 types of neoplasms may be treated with interferons?

A

Renal cell carcinoma, malignant melanoma, Kaposi sarcoma, hairy cell leukemia, condyloma acuminatum

216
Q

Which general type of vaccine is contraindicated in pregnant patients or patients with immunodeficiencies?

A

Live attenuated vaccines

217
Q

What are the 3 main functions of interleukin-4?

A

Interleukin 4 induces T-cell differentiation into Th (helper) 2 cells, promotes B-cell growth, enhances class switching to IgE and IgG (ain’t too proud 2 BEG 4 help)

218
Q

Anaphylaxis (eg, bee sting, some food/drug allergies) is what type of hypersensitivity reaction?

A

Type I

219
Q

What is the main function of interleukin-3?

A

Supports growth and differentiation of stem cells in the bone marrow; functions like GM-CSF

220
Q

What is the T-cell in vitro response to Candida antigens in patients with chronic mucocutaneous candidiasis?

A

Lack of T-cell proliferation

221
Q

A patient develops hives, fever, and shock within minutes of receiving blood transfusion. What is the pathogenesis behind this transfusion reaction?

A

Type I hypersensitivity reaction against plasma proteins in the transfused blood (this is an allergic/anaphylactic reaction)

222
Q

What are the 4 domains that comprise the Fab region of an antibody?

A

Variable light region (VL), constant light region (CL), variable heavy region (VH), constant heavy 1 region (CH1)

223
Q

In what situation do T and B cells become anergic?

A

T and B cells become nonreactive when they do not receive a costimulatory signal (signal 2) on exposure to an antigen

224
Q

Which type of immune cell secretes interleukin-6?

A

Macrophages

225
Q

Each B cell produces an immunoglobulin specific to 1 antigen. How is antibody specificity established?

A

1) Somatic hypermutation and affinity maturation for the variable region (Fab); 2) isotype switching for the constant region (Fc)

226
Q

Interferons can prime local cells for self-defense against viruses by inducing upregulation of what process?

A

MHC expression, so as to facilitate recognition of infected cells

227
Q

A patient has thymic aplasia in the setting of DiGeorge syndrome. For what 5 types of viral infections is he at risk?

A

CMV, EBV, JCV, VZV, and chronic GI/respiratory viruses

228
Q

Despite having low serum concentrations, IgA is the most abundantly produced antibody. Where is it made?

A

The gastrointestinal tract (by Peyer patches); it is released into secretions (tears, saliva, mucus)

229
Q

Although most individuals with IgA deficiency have no symptoms, what symptoms can be present that allow for diagnosis?

A

Airway and GI infections, Autoimmune disease, Atopy, and Anaphylaxis to IgA-containing products

230
Q

Name the gene affected in Bruton agammaglobulinemia.

A

BTK, which encodes for Bruton tyrosine kinase

231
Q

How soon after exposure to an antigen does the immediate phase of a type I hypersensitivity reaction occur?

A

Minutes after antigen exposure

232
Q

Which complement protein combines with C6–C9 to form the membrane attack complex (MAC)?

A

C5b

233
Q

What is the means of acquisition of passive immunity?

A

Transfer of preformed antibodies

234
Q

Which immunoglobulin isotype protects mucous membranes from invading pathogens?

A

IgA

235
Q

Which antibody regions contain the variable/hypervariable regions and the constant region?

A

Fab contains the variable/hypervariable regions, and a small constant region; Fc contains the constant regions only

236
Q

Unlike other immunoglobulin (Ig) isotypes, the function of IgD is unclear. Where can immunoglobulin D be found?

A

Surface of many B cells and in serum

237
Q

A boy has coarse facies, retained baby teeth, and recurrent abscesses. Labs show ↑ IgE and ↑ eosinophils. Which immune cells are impaired?

A

Th17 cells (he has hyper-IgE syndrome [Job syndrome])

238
Q

Which cell surface proteins are common to all B cells?

A

Immunoglobulin (Ig), CD19, CD20, CD21, CD40, MHC II, B7

239
Q

For which malignancies can interferons be used as a form of therapy?

A

Hairy cell leukemia, renal cell carcinoma, malignant melanoma, Kaposi sarcoma

240
Q

A patient has a parasite infection. In a tissue biopsy, eosinophils are seen attacking the parasites due to signaling by which immunoglobulin?

A

IgE

241
Q

A neonate breastfeeds for the first time, receiving abundant maternal IgA in colostrum. How long is this type of immune protection likely to last?

A

No more than 3 wk (the half-life of an antibody), as this is a form of passive immunity

242
Q

A kidney transplant recipient experiences gradual oliguria. Biopsy reveals vasculitis of graft vessels with a lymphocytic cellular infiltrate. What type of rejection is present?

A

Acute rejection

243
Q

A previously healthy woman, not taking any medications, develops dry eyes and dry mouth. What autoantibodies can cause this?

A

Anti-Ro/SSA and anti-La/SSB autoantibodies, often positive in Sjögren syndrome

244
Q

What are the 4 Cs to remember about the Fc fragment of an antibody?

A

Constant region, Carboxy terminal, Complement binding, Carbohydrate side chains

245
Q

Which receptors found on macrophages enhance their phagocytic activity?

A

Fc and C3b receptors

246
Q

What are the manifestations of velocardiofacial syndrome?

A

Facial and palate defects and cardiac anomalies

247
Q

Antibodies are made up of heavy and light chains. Which chains contribute to the Fab and Fc regions?

A

Light chains contribute to Fab region only; heavy chains contribute to both Fab and Fc regions

248
Q

Antibodies are made up of the Fab and Fc regions. What is the function of each region in immunity?

A

Fab region recognizes antigen (Fragment, antigen binding); Fc region fixes complement for IgM and IgG isotypes

249
Q

A 30-year-old woman has bulging eyes, palpitations, diarrhea, and thyromegaly. What autoantibodies cause this condition?

A

Anti-TSH receptor autoantibodies (she has Graves disease)

250
Q

A child has recurrent bacterial skin infections with absence of pus and impaired wound healing. What findings might confirm the diagnosis?

A

Increased serum neutrophil levels but lack of neutrophils at infection sites (this is type 1 leukocyte adhesion deficiency)

251
Q

Patients with hyper-IgM syndrome are more susceptible to infection by which opportunistic organisms?

A

CMV, Cryptosporidium, Pneumocystis,

252
Q

What autoantibodies are present in pemphigus vulgaris?

A

Anti-desmosome (anti-desmoglein) autoantibodies

253
Q

Mature, naive B cells express what immunoglobulin (Ig) isotypes on their surfaces before class switching?

A

IgM and IgD

254
Q

What are the 3 major types of interferons?

A

IFN-α, IFN-β, IFN-γ

255
Q

A pneumococcal vaccine PCV13 is recommended for infants and young children. Does the antigen contain a peptide component?

A

Yes; the vaccine contains a thymus-dependent antigen, which contains a protein component

256
Q

What are the characteristic lab findings in Wiskott-Aldrich syndrome?

A

Normal/decreased IgG and IgM, elevated IgE and IgA, thrombocytopenia with microsized platelets

257
Q

A patient receives the oral Sabin polio vaccine. Is there a risk of the vaccine producing poliovirus infection in this patient?

A

Yes, but a very small one (as the Sabin vaccine is a live attenuated vaccine, which may revert to a virulent form)

258
Q

What are the 2 mechanisms whereby interferons aid in the immune response against viral infection?

A

Upregulation of MHC expression (improving immune recognition of infected cells) and downregulation of protein synthesis (blocking viral replication)

259
Q

Trace the alternative pathway from C3 all the way to the cleavage of C5.

A

C3 is cleaved into C3b → C3b + Bb → C3bBb (C3 convertase) + C3b → C3bBb3b (C5 convertase) cleaves C5 into C5a/b

260
Q

A young boy has failure to thrive due to recurrent infections with various pathogens and chronic diarrhea. Thymic shadow is not seen on chest x-ray. Curative treatment?

A

Bone marrow transplant, for which graft rejection is not a concern (he has severe combined immunodeficiency)

261
Q

What is a specific pathologic manifestation of chronic rejection in a transplanted lung?

A

Bronchiolitis obliterans

262
Q

What is the name for the specific piece of the antigen to which an antibody binds?

A

Epitope

263
Q

A boy has defective NADPH oxidase; his neutrophils produce fewer ROS. Which organism(s) is he most susceptible to?

A

Catalase-positive organisms (diagnosis: chronic granulomatous disease)

264
Q

What autoantibodies are associated with granulomatosis with polyangiitis (Wegener)?

A

PR3-ANCA (c-ANCA)

265
Q

Which 2 types of immune cells secrete interferon-γ?

A

Th1 cells and NK cells

266
Q

List 4 main functions of IgG.

A

Fixation of complement, opsonization of bacteria, neutralization of bacterial toxins and viruses, provision of passive immunity to infants via placenta

267
Q

What live viral vaccine is nonattenuated and only given to military recruits?

A

Adenovirus

268
Q

How soon after exposure to an antigen does the late phase of a type I hypersensitivity reaction occur?

A

Hours after antigen exposure

269
Q

What type of infections are seen in patients with common variable immunodeficiency?

A

Sinopulmonary infections

270
Q

What are the 2 main functions of interleukin-12?

A

Activates natural killer cells, induces differentiation of T cells to Th1 cells

271
Q

Bruton agammaglobulinemia, selective IgA deficiency, and common variable immunodeficiency are disorders of which type of leukocyte?

A

B Cells

272
Q

Name the defective gene in Chédiak-Higashi syndrome.

A

Lysosomal trafficking regulator gene (LYST)

273
Q

A child with an inherited immune disorder has greasy, foul-smelling stools. What type of immunodeficiency is likely?

A

B-cell deficiency with no IgA (giardiasis), leading to lack of mucosal immunity

274
Q

A developing fetus receives passive immunity from his mother in utero. What subtype of immunoglobulin is transferred across the placenta?

A

IgG

275
Q

Name 5 examples of type III hypersensitivity reactions.

A

Serum sickness, Arthus reaction, systemic lupus erythematosus, polyarteritis nodosa, poststreptococcal glomerulonephritis

276
Q

Which cell surface protein is unique to cytotoxic T cells?

A

CD8

277
Q

Describe the mechanism of the late phase of a type I hypersensitivity reaction.

A

After mast cell degranulation, chemokines attract inflammatory cells and other mediators from mast cells, leading to inflammation and tissue damage

278
Q

For which autoimmune condition are interferons particularly effective?

A

Multiple sclerosis

279
Q

Graft-versus-host disease is what type of hypersensitivity reaction?

A

Type IV

280
Q

What are the 3 methods by which one can acquire active immunity to an antigen?

A

Natural infection, toxoid exposure, vaccination

281
Q

For which infections can interferons be used as a form of therapy?

A

Chronic HBV and HCV, condyloma acuminatum

282
Q

Which cytokine from Th2 cells enhances class switching to IgA?

A

Interleukin-5

283
Q

Which type of immune cell secretes interleukin-8?

A

Macrophages

284
Q

What is the mechanism of injury in transfusion-related acute lung injury?

A

It is due to donor anti-leukocyte antibodies attacking the recipient’s neutrophils and pulmonary endothelial cells

285
Q

Interferons are what specific type of macromolecule?

A

Glycoproteins

286
Q

To what specific region(s) of the heavy chain does complement bind?

A

CH2 region

287
Q

A pale, blond patient has recurrent pyogenic infections, lymphohistiocytosis, and neuropathy. Pancytopenia is noted. What cellular process is affected in this condition?

A

Microtubule dysfunction impairing phagosome-lysosome fusion (this is Chédiak-Higashi syndrome)

288
Q

What antibodies are associated with autoimmune hepatitis type 1?

A

Anti-smooth muscle autoantibodies

289
Q

What is a specific pathologic manifestation of chronic rejection in a transplanted kidney?

A

Chronic graft nephropathy

290
Q

Describe the difference between a direct and an indirect Coombs test.

A

Direct: detects antibodies that are already bound to RBCs; indirect: detects free serum antibodies that can bind to RBCs

291
Q

A 2-year-old child with recurrent severe pyogenic bacterial infections has high IgM levels and low levels of all other immunoglobulins. What is the diagnosis?

A

Hyper-IgM syndrome

292
Q

Name the 3 autoantibodies associated with Hashimoto thyroiditis.

A

Antimicrosomal, antithyroglobulin, and antithyroid peroxidase autoantibodies

293
Q

Which 2 types of immune cells secrete interleukin-10?

A

Th2 cells and regulatory T cells

294
Q

Which complement proteins combine to form the membrane attack complex (MAC) to mediate cytolysis?

A

C5b, C6, C7, C8, and C9

295
Q

What is the temporal onset and duration of active immunity?

A

Slow onset but long-lasting immune protection (memory)

296
Q

What are the 4 T’s associated with type IV hypersensitivity reactions?

A

T cells, Transplant rejections, TB skin tests, and Touching (contact dermatitis)

297
Q

What is a specific pathologic manifestation of chronic rejection in a transplanted heart?

A

Accelerated atherosclerosis

298
Q

Anti-phospholipase A2 receptor autoantibodies are associated with which disorder?

A

Primary membranous nephropathy

299
Q

What are the 5 manifestations of Chédiak-Higashi syndrome?

A

PLAIN: Progressive neurodegeneration, Lymphohistiocytosis, Albinism (partial), recurrent pyogenic Infections, and peripheral Neuropathy

300
Q

Which immunoglobulin (Ig), passed from mother to infant, is responsible for passive immunity after birth? How long does it last?

A

IgG, which can cross the placenta; passive immunity starts to wane after 6 mo

301
Q

What 2 organs are typically absent in DiGeorge syndrome?

A

Thymus and parathyroid glands

302
Q

What is the main function of interleukin-2?

A

Stimulates growth of helper T cells, cytotoxic T cells, regulatory T cells, and natural killer cells

303
Q

Which complement protein attracts neutrophils to the site of infection?

A

C5a

304
Q

Type IV hypersensitivity reactions can occur by 2 mechanisms. Describe the direct cell cytotoxicity mechanism.

A

Target cells are killed by CD8+ cytotoxic T cells

305
Q

A mother is Rh- and her fetus may be Rh+. Which Coombs test should each of them receive?

A

Test mother blood for Rh+ antibodies with indirect Coombs test; test fetal blood for antibodies adhered to RBCs with direct Coombs test

306
Q

A patient has recurrent infections with encapsulated organisms. His B-cell counts are normal. What other defect may be to blame?

A

Early complement deficiency

307
Q

What is the pathogenetic mechanism whereby acute cellular rejection develops?

A

CD8+ T cells and/or CD4+ T cells are activated against foreign (donor) MHCs in a type IV hypersensitivity reaction

308
Q

All immunoglobulin isotypes can exist in which structural form: monomers or polymers?

A

Monomers

309
Q

What is the mechanism of complement-mediated hemolysis in paroxysmal nocturnal hemoglobinuria?

A

Lack of GPI anchors needed for binding of complement inhibitors (eg, decay-acclerating factor) results in complement-mediated intravascular hemolysis → ↓ haptoglobin → dark urine

310
Q

A patient with odynophagia and thrush is likely to have a deficiency of what type of immune cell?

A

T cells, as this patient has a (local) Candida esophagitis causing painful swallowing (by contrast, systemic infections occur in patients with granulocyte deficiencies)

311
Q

What type of hypersensitivity reaction is involved in graft-versus-host disease (GvHD)?

A

Type IV hypersensitivity

312
Q

A 6-year-old girl with nausea, vomiting, urinary frequency, and sudden weight loss has a blood glucose level of 800 mg/dL. What autoantibodies should be ordered on labs?

A

Anti-glutamic acid decarboxylase and islet cell cytoplasmic autoantibodies (to check for type 1 diabetes)

313
Q

The NK and Th1 cells within a virus-infected host are stimulated by interleukin-12. Which cytokine will be secreted by these cells in response?

A

Interferon-γ

314
Q

Which typhoid vaccine is capable of producing a stronger immune response?

A

The Ty21a typhoid vaccine, which is a live attenuated (and therefore stronger) vaccine

315
Q

A patient with no recorded medical history presents with angioedema. His father also had similar episodes. What is the pathophysiology of the disease?

A

Unregulated activation of kallikrein leading to ↑ bradykinin levels (this is hereditary angioedema due to C1 esterase inhibitor deficiency)

316
Q

Interferons can prime local cells for self-defense against viruses by inducing downregulation of what process?

A

Protein synthesis, so as to resist potential viral replication

317
Q

A patient with bronchiectasis produces blue-green sputum when she coughs. Which enzyme in neutrophils gives the sputum its color?

A

Myeloperoxidase, which contains a blue-green, heme-containing pigment

318
Q

Reaction to PPD (a test for Mycobacterium tuberculosis) is what type of hypersensitivity reaction?

A

Type IV

319
Q

When do cells generally synthesize interferons?

A

When infected by viruses (interferons interfere with both DNA and RNA viruses)

320
Q

Describe the mechanism common to all type II hypersensitivity reactions.

A

Antibodies bind to cell surface antigens, leading to cellular destruction, cellular dysfunction, and inflammation

321
Q

What pathogenetic mechanism drives the development of graft-versus-host disease?

A

Grafted immunocompetent T cells proliferate in the immunocompromised host and reject cells with foreign proteins, causing severe organ dysfunction

322
Q

What is the means of acquisition of active immunity?

A

Exposure to foreign antigens

323
Q

Which type of influenza vaccine is theoretically safer for most patients to receive?

A

The injected influenza vaccine, which is killed/inactivated (unlike the intranasal influenza vaccine, which is live attenuated)

324
Q

What is another name for interleukin-1?

A

Osteoclast-activating factor

325
Q

How rapidly does acute (cellular or humoral) transplant rejection develop?

A

Within weeks to months of transplantation

326
Q

Describe the mechanism of a type III hypersensitivity reaction.

A

Anitigen-antibody complexes activate complement, attracting neutrophils that release lysosomal enzymes

327
Q

Early complement (C1–C4) deficiencies are associated with increased risk of which autoimmune disease?

A

Systemic lupus erythematosus

328
Q

A child completes the routine vaccination series for measles, mumps, and rubella (MMR). How long is this protection likely to last?

A

Throughout his or her life, as vaccines confer active immunity (with long-lasting protection from activation of immune memory)

329
Q

A patient has a butterfly rash and photosensitivity after initiation of isoniazid therapy. What autoantibodies are specific for this condition?

A

Anti-histone autoantibodies (this is drug-induced lupus)

330
Q

How rapidly does hyperacute transplant rejection develop?

A

Within minutes of transplantation

331
Q

Which cell surface protein on B cells binds antigen?

A

Immunoglobulin (Ig)

332
Q

Goodpasture syndrome, rheumatic fever, and hyperacute transplant rejection exemplify what type II hypersensitivity mechanism?

A

Inflammation, in which cell opsonization leads to complement system activation and Fc receptor–mediated inflammation

333
Q

What are the adverse effects of interferon therapy?

A

Flu-like symptoms, depression, neutropenia, myopathy, interferon-induced autoimmune conditions

334
Q

Patients with hyper-IgE syndrome (Job syndrome) likely to experience what type of injuries?

A

Bone fractures, which can result from even minor trauma

335
Q

List the symptoms of hyper-IgE (Job) syndrome using the mnemonic ABCDEF.

A

Noninflamed staphylococcal Abscesses, retained Baby teeth, Coarse facies, Dermatologic problems (eczema), high IgE, Fractures from minor trauma (Learn the ABCDEF’s to get a Job!)

336
Q

Allergic and atopic disorders (eg, rhinitis, hay fever, eczema, hives, asthma) are what type of hypersensitivity reaction?

A

Type I

337
Q

Pseudomonas aeruginosa cultures can kill competing bacteria with high levels of reactive oxygen species (ROS). How does this occur?

A

P aeruginosa produces pyocyanin, which can generate ROS to kill competing microbes

338
Q

What 2 immunoglobulin (Ig) isotypes are involved in fixation of complement?

A

IgG and IgM

339
Q

How can the stimulatory effects of interleukin (IL)-1, IL-2, IL-3, IL-4, IL-5, and IL-6 be summarized?

A

IL-1 = fever (Hot), IL-2 = T cells, IL-3 = bone marrow, IL-4 = IgE, IL-5 = IgA, IL-6 = aKute-phase proteins (Hot T-bone stEAK)

340
Q

Which autoantibody is a nonspecific screening marker for several autoimmune disorders, often associated with SLE?

A

Antinuclear antibody (ANA)

341
Q

A woman presents with ptosis and muscle weakness that progressively worsens by the end of the day. What antibodies are responsible for this disease?

A

Autoantibodies against acetylcholine receptors (she has myasthenia gravis)

342
Q

What gene mutation leads to autosomal dominant hyper-IgE syndrome (Job syndrome)?

A

STAT3 mutation, which leads to Th17 deficiency, resulting in impaired neutrophil recruitment

343
Q

Which 2 types of hypersensitivity reactions are implicated in the development of chronic transplant rejection?

A

Type II and IV hypersensivity (involving both humoral and cellular components)

344
Q

What are the 3 ways by which antibody-mediated pathogen elimination occurs?

A

Opsonization, neutralization, and complement activation

345
Q

Autoimmune hemolytic anemia, ITP, transfusion reaction, and newborn hemolytic disease exemplify which mechanism of type II hypersensitivity?

A

Cellular destruction in which cells are opsonized and then undergo either NK cell killing or phagocytosis and/or complement system activation

346
Q

An OR nurse sustains an accidental needlestick injury during a liver transplant procedure on a patient with hepatitis B cirrhosis. What treatment should be given to the nurse?

A

Combined passive and active immunization (ie, postexposure prophylaxis with preformed anti-HBV antibodies and the recombinant HBV vaccine)

347
Q

Which 2 cytokines function in the recruitment of immune cells after the initial phase of acute inflammation?

A

Interleukin-8, interleukin-12; think “acute (IL-1, IL-6, TNF-α), then recruit (IL-8, IL-12)”

348
Q

Anticardiolipin autoantibodies and the lupus anticoagulant are associated with which disorders?

A

SLE and antiphospholipid syndrome

349
Q

A patient develops respiratory distress due to noncardiogenic pulmonary edema within 4 hours of receiving blood products. What is the cause?

A

Transfusion-related acute lung injury

350
Q

What lab findings might be seen in patients with C1 esterase inhibitor deficiency?

A

Decreased C4 level

351
Q

The phagocyte NADPH oxidase complex utilizes what molecule as a substrate?

A

Oxygen

352
Q

A patient is found to be positive for HBsAg and HBeAg and is treated with interferon. What would happen to the number of MHC molecules expressed on his hepatocytes?

A

Increased concentrations of MHC molecules would be observed (interferons increase MHC expression)

353
Q

A patient develops worsening edema and necrosis at the site of recent tetanus vaccination. What is the diagnosis?

A

Arthus reaction: preformed antibodies attack injected antigen leading to formation of immune complexes in the skin and complement activation

354
Q

A patient with rheumatoid arthritis being treated with a TNF-α inhibitor gradually begins to experience hemoptysis and night sweats. How might this occur?

A

TNF-α maintains granulomas in TB, so inhibition of this cytokine can lead to reactivation of latent TB

355
Q

What is the pathogenesis of chronic mucocutaneous candidiasis?

A

Impaired cell-mediated immunity against Candida classically caused by defects in the AIRE gene; however, various immune system defects may contribute

356
Q

A patient with poorly controlled eosinophilic asthma is treated with an inhibitor of interleukin-5. How might this drug reduce symptoms of asthma?

A

Suppression of interleukin-5 will dampen the eosinophilic inflammatory response (as interleukin-5 stimulates eosinophil differentiation)

357
Q

A 20-year-old man has severe, recurrent pyogenic respiratory tract infections. Which complement disorder should be considered in the differential?

A

Early complement (C1–C4) deficiencies

358
Q

What is the main function of interleukin-8?

A

Promotes neutrophil chemotaxis (“clean up on aisle 8”; neutrophils are recruited by IL-8 to clear infections)

359
Q

Which vaccine against Salmonella typhi poses a lower risk of causing infection?

A

The intramuscular Vi polysaccharide typhoid vaccine, which is killed/inactivated

360
Q

TGF-β has the same attenuating effect on the immune system as which cytokine?

A

Interleukin-10 (TGF-β and interleukin-10 both attenuate the immune response)

361
Q

What end product of oxygen-dependent respiratory burst is used to kill bacteria in the phagolysosome?

A

Bleach (HOCl•), also known as hypochlorite

362
Q

What is another name for respiratory burst?

A

Oxidative burst

363
Q

A patient has a history of several miscarriages and venous thromboses. Labs show prolonged PTT. What autoantibodies are associated with this syndrome?

A

Anti-β2 glycoprotein I, lupus anticoagulant, and anticardiolipin autoantibodies (she has antiphospholipid syndrome)

364
Q

A young girl develops hematuria a few weeks after an episode of streptococcal pharyngitis. What type of hypersensitivity reaction is responsible for the disease?

A

Type III (she has poststreptococcal glomerulonephritis)

NBME Micro (36 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions