428. A 13-year-old male with cystic fibrosis develops repeated episodes of pneumonia resulting in multiple hospitalizations. Previous antibiotic treatment resulted in severe rash, fever, and systemic anaphylaxis almost immediately. A penicilloyl polylysine skin test yields positive results. Which of the following best illustrates the type of hypersensitivity reaction associated with this clinical scenario?
a. Type I
b. Type II
c. Type III
d. Type IV
429. After playing in the bushes during a camping trip, a 7-year-old girl complains of intense itching and blistering of the hands, arms, and legs. Which of the following are the most likely medical condition and the correct hypersensitivity diagram from those presented?
a. Contact dermatitis and type II
b. Contact dermatitis and type III
c. Contact dermatitis and type IV
d. Arthus reaction and type I
e. Arthus reaction and type II
f. Arthus reaction and type III
430. Skin testing is useful in the diagnosis of which of the following?
a. Type I and II
b. Type I and III
c. Type I and IV
d. Type II, III, and IV
431. Rh disease and Goodpasture syndrome are best represented by which of the following?
a. Type I and II
b. Type II and III
c. Type II and IV
d. Type II only
e. Type III only
Questions 432 and 433
432. A 7-month-old male infant presents to the emergency department with severe middle ear and upper respiratory tract infections, which respond promptly to antibiotics. Two months later he is again admitted, this time with Streptococcus pneumoniae pneumonia. After several more episodes of bacterial infections, genetic testing is done and the presence of a defective B-cell tyrosine kinase gene (btk gene or X-LA gene) is revealed. In addition, physical examination detects very small tonsils. Which of the following is the most likely diagnosis?
a. Ataxia-telangiectasia
b. Bruton agammaglobulinemia
c. Chronic granulomatous disease
d. Late (C5, C6, C7, C8, C9) complement deficiency
e. Thymic aplasia (DiGeorge syndrome)
433. Which of the following pathogens presents the most serious threat to this child?
a. Chlamydia trachomatis
b. Measles virus
c. Mycobacterium tuberculosis
d. Varicella-zoster virus (VZV)
Questions 434 and 435
Flow cytometry of blood from an HIV-positive patient yielded a CD4:CD8 ratio less than 1.
434. This ratio best represents a major decline in which of the following cell types and its associated cell surface proteins?
a. B lymphocytes; MHC class I, IgM, B7, CD19, CD20
b. Cytotoxic T lymphocytes; MHC class I, TCR, CD3
c. Cytotoxic T lymphocytes; MHC class I, TCR, CD3, CD28
d. Helper T lymphocytes; MHC class I, TCR, CD3
e. Helper T lymphocytes; MHC class I, TCR, CD3, CD28
f. Macrophages; MHC class I, MHC class II, CD14
435. Which of the following best represents the “costimulatory signal” pair that occurs between cellular surface proteins associated with the reduced cell type represented in the CD4:CD8 ratio less than 1?
a. B7 (B cell) and CD28 (T cell)
b. B7 (B cell) and CD4 (T cell)
c. CD40L (B cell) and CD40 (T cell)
d. MHC class I (B cell) and CD4 (T cell)
e. MHC class II (B cell) and CD8 (T cell)
436. A young girl has had repeated infections with Candida albicans and respiratory viruses since she was 3 months old. As part of the clinical evaluation of her immune status, her responses to routine immunization procedures should be tested. In this evaluation, the use of which of the following vaccines is contraindicated?
a. Bacillus Calmette–Guerin (BCG)
b. Bordetella pertussis vaccine
c. Diphtheria toxoid
d. Inactivated polio
e. Tetanus toxoid
437. A 7-year-old male developed normally until 7 years of age, after which he suddenly starts suffering from progressive personality and intellect deterioration leading to dementia, and finally death within 1 year of symptoms. His history reveals severe measles attack at the age of 1. Laboratory tests indicate elevated measles antibody levels in both the serum and cerebrospinal fluid (CSF) with no antibody to the M protein. A latent measles-like viral infection and, presumably, a defect in cellular immunity are associated with which of the following diseases?
a. Creutzfeldt–Jakob disease (CJD)
b. Epstein–Barr virus (EBV) infection
c. Multiple sclerosis (MS)
d. Progressive multifocal leukoencephalopathy (PML)
e. Subacute sclerosing panencephalitis (SSPE)
438. A 31-year-old patient suffering from recurrent episodic intestinal hemorrhages attributed to a severe form of Crohn disease decides to undergo surgery to resect his terminal ileum. The surgeon orders two units of blood to be preserved for possible use during the surgery. The patient decides to store one unit of his own blood and one unit of his 35-year-old brother’s blood with the blood bank. This type of donation is most likely which of the following transplantation terminology (patient’s blood:brother’s blood)?
a. Allograft:allograft
b. Allograft:autograft
c. Autograft:allograft
d. Autograft:autograft
e. Autograft:isograft (syngeneic graft)
439. A 27-year-old female presents to the emergency room with a temperature of 103°F, severe fatigue, weight loss, and joint pain. During the history and physical examination, the patient reports that she stopped taking her aspirin and corticosteroids to control her condition. A butterfly-type rash over her cheeks, sensitivity to light, and a heart murmur are apparent. The patient also reports a history of a progressively developing arthritis and glomerulonephritis. Laboratory tests further indicate anemia, leukopenia, and thrombocytopenia. This condition is best diagnosed by the presence of which of the following?
a. Anticentromere antibodies
b. Anti-dsDNA antibodies
c. Antimitochondrial antibodies
d. Antineutrophil antibodies
e. Anti-TSH receptor antibodies
440. A 1-year-old male patient presents with marked susceptibility to opportunistic infections with bacteria such as Escherichia coli and Staphylococcus aureus and fungal Aspergillus. Examination findings reveal granulomatous abscesses in the lungs, ataxia, nystagmus, and photophobia. Biochemical analysis reveals the deficiency of the central enzyme in the respiratory burst pathway via an inability to reduce nitroblue tetrazolium (NBT) dye. The deficient enzyme and reaction are represented by which of the following?
441. Which of the following statements best applies to the following diagram?
(Modified, with permission, from Parslow TG, et al. Medical Immunology. 10th ed. New York, NY: McGraw-Hill; 2001:85.)
a. Depicts the cell-membrane MHC product associated with narcolepsy
b. Essential for the transplacental passage of antibody
c. Found on T and B lymphocytes and all nucleated cells
d. Present on macrophages but not neutrophils
e. Represents the secretory component associated with IgA
f. Required for recognition of processed antigen by TH1 and TH2 lymphocytes
442. A 19-year-old college student develops a rash. She works part-time in a pediatric AIDS clinic. Her blood is drawn and tested for specific antibody to the chicken pox virus (varicella-zoster). Which of the following antibody classes would you expect to find if she is immune to chicken pox?
a. IgG
b. IgA
c. IgM
d. IgD
e. IgE
443. Patients with C5 through C9 complement deficiencies are most likely to be susceptible to which of the following infections?
a. AIDS
b. Giardiasis
c. Histoplasmosis
d. Neisserial infection
e. Pneumococcal infection
444. As part of the management of a 28-year-old male with acute onset of Crohn disease of the small bowel, you decide to treat him with a new cocktail of mouse–human chimeric antibodies to reduce his intestinal inflammation and cachexia. To which of the following sets of proteins are these antibodies directed?
a. IL-1, IL-2, IL-3
b. IL-2, IL-12, TNF-α
c. IL-2, TGF-β, TNF-α’
d. IL-1, IL-6, TNF-α’
e. IL-2, IL-3, IL-12
445. A mother and newborn are exposed to a pathogen while at the hospital for a routine checkup and breastfeeding clinic. This same pathogen had infected the mother about a year previously, and she had successfully recovered from the subsequent illness. Immunity may be innate or acquired. Which of the following best describes acquired immunity with respect to the newborn?
a. Complement cascade
b. Increase in C-reactive protein (CRP)
c. Inflammatory response
d. Maternal transfer of antibody
e. Presence of natural killer (NK) cells
446. A 35-year-old male patient presents with numerous subcutaneous hemorrhages. History and physical examination reveal that he has been taking sedormid (a sedative) for the past week. Laboratory tests indicate normal hemoglobin and white blood cell levels with significant thrombocytopenia (very low platelet count). You suspect that he has developed a drug-induced type II hypersensitivity reaction. This reaction may occur if the drug does which of the following?
a. Activates T cytotoxic cells
b. Acts as a hapten
c. Induces mast cell degranulation, releasing mediators such as histamine, leukotrienes, and prostaglandins
d. Induces oxygen radical production through the respiratory burst pathway
e. Persists in macrophages
447. After learning of a family history of humoral immunity deficiency during an office visit from a patient 6 months pregnant, a radial immunodiffusion assay is ordered on fetal serum. The test reveals no humoral immunity problems and normal results in all respects. According to this test, the normal level of which fetally made immunoglobulin is the highest in the fetus?
a. IgA
b. IgD
c. IgE
d. IgG
e. IgM
448. A 31-year-old male patient complains of fatigue, yeast infection in his mouth, and enlarged lymph nodes under his arms. He says that he was involved in “high-risk” behavior 6 years ago while on a trip to eastern and southern Africa. He also indicates that his “HIV test” was negative. Which of the following options is most appropriate?
a. Initiate treatment for HIV disease
b. Order a test for human T-cell leukemia virus (HTLV)
c. Order an HIV-1 RNA PCR
d. Order an HIV test that would include antibodies to HIV-1 and HIV-2
e. Repeat the test for HIV-1
449. A laboratory analysis report of a specific fraction of a patient’s lymphocytes indicates the following: HLA, B, and C+, PHA+, CD3–, CD16+, CD11a/CD18+, CD56+, and in vitro blastogenesis with IL-12. What are the lymphocytes that this set describes?
a. B lymphocytes
b. Cytotoxic T lymphocytes
c. NK cells
d. T helper 1 (TH1) subset
e. T helper 2 (TH2) subset
450. The complement system plays a key role in the host defense process. Which of the following components of this system is the most important in chemotaxis?
a. C1q
b. C3a
c. C3b
d. C4a
e. C5a
451. Soon after birth, a newborn undergoes heart transplantation surgery at a local medical center. Transplantation of tissue and organs is a common procedure whose success depends largely on the “self” versus “nonself” interactions. Survival of allografts is increased by choosing donors with few major histocompatibility complex (MHC) mismatches compared to recipients and by use of immunosuppression in recipients. Which of the following procedures is the most useful measure of immunosuppression in recipients?
a. Administration of corticosteroids to recipient
b. Administration of immunoglobulin to recipient
c. Destruction of donor B cells
d. Destruction of donor T cells
e. Lymphoid irradiation of donor
452. Relative to the primary immunological response, secondary, and later booster responses to a given hapten–protein complex can be associated with which one of the following?
a. Antibodies that are less efficient in preventing specific disease
b. Decreased antibody avidity for the original hapten–protein complex
c. Increased antibody affinity for hapten
d. Lower titers of antibody
e. Maintenance of the same subclass, or idiotype, of antibody produced
453. You are managing a 3-year-old female patient with a fever of unknown origin. Her serum is tested for antibodies against Haemophilus influenzae. A precipitation test conducted by the clinical laboratory yields the following results:
From these data, which of the following can be concluded?
a. The negative reactions at 1:128 and 1:126 are false negatives
b. The patient has antibodies against H. influenzae, the titer is 64, and the dilution 1:64
c. The patient has antibodies against H. influenzae, the dilution is 64, and the titer 1:64
d. The patient does not have antibodies against H. influenzae since the reaction is negative with undiluted serum
e. The patient should be immunized against H. influenzae
454. Of the five immunoglobulin classes, IgA is the main immunoglobulin of secretions from the genital, respiratory, and intestinal tracts. As a result, IgA antibody is the first line of defense against infections at the mucous membrane. It is usually an early specific antibody. Which of the following statements most accurately describes IgA?
a. Complement fixation tests for IgA antibody will be positive if specific IgA antibody is present
b. IgA can be destroyed by bacterial proteases
c. IgA is absent in colostrum
d. IgA is not found in saliva; therefore, an IgA diagnostic test on saliva would have no value
e. IgA is a small molecule with a molecular weight of 30,000 kDa
455. A 60-year-old male presents with severe jaundice to the local walk-in clinic. History and physical examination reveal a 30-year history of alcohol consumption and drug abuse. Blood tests reveal elevated AST and ALT levels and the presence of hepatitis B and, as a result, reduced complement levels. Complement is a series of important host proteins that provide protection from invasion by foreign microorganisms. Which of the following best describes complement?
a. Complement inhibits phagocytosis
b. Complement is activated by IgE antibody classes
c. Complement plays a minor role in the inflammatory response
d. Complement protects the host from pneumococcal infection through C1, C2, and C4
e. Microorganisms agglutinate in the presence of complement but do not lyse
456. Radial immunodiffusion and immunoelectrophoresis is performed on a young patient to evaluate the function of his humoral immune system. Which of the following immunoglobulins has no known function, is found in the serum in low concentrations, and is present on the surface of B lymphocytes (may function as an antigen receptor)?
a. IgG
b. IgA
c. IgM
d. IgD
e. IgE
457. A young patient with severe recurrent pyogenic bacterial infections, but with normal T-cell and B-cell numbers, arrives at the hospital. Testing reveals that this patient’s CD4 T-helper cells have a defect in CD40 ligand. As a result, humoral immunity evaluation reveals a significant elevation in the levels of which immunoglobulin that is present as a monomer on B-cell surfaces, as a pentamer in serum, and is initially seen in the primary immune response?
a. IgG
b. IgA
c. IgM
d. IgD
e. IgE
458. A patient with a long history of consuming poorly cooked pork meat presents with generalized myalgia and a low-grade fever. Striated muscle biopsy reveals multiple cysts. Eosinophilia is also present with elevated levels of which of the following immunoglobulins most likely involved in parasitic infections?
a. IgG
b. IgA
c. IgM
d. IgD
e. IgE
459. A patient with cerebellar problems and spider angiomas is diagnosed with a combined T-cell and B-cell deficiency known as ataxia-telangiectasia. In addition to a defect in this patient’s DNA repair enzymes, which immunoglobulin is the primary antibody in saliva, tears, and intestinal and genital secretions, and is also deficient in this illness?
a. IgG
b. IgA
c. IgM
d. IgD
e. IgE
460. With four subclasses, which immunoglobulin is the predominant antibody in the secondary immune response and has the greatest concentration of the five immunoglobulin classes in the fetus?
a. IgG
b. IgA
c. IgM
d. IgD
e. IgE
461. A 15-year-old boy is bitten by an Ixodes tick while camping with his parents and presents 1 week later with fatigue, fever, headache, and a reddish rash over his trunk and extremities. Positive IgM antibody (1:200) to Borrelia burgdorferi is associated with which of the following?
a. Acute Lyme disease
b. Fifth disease
c. Possible hepatitis B infection
d. Possible subacute sclerosing panencephalitis (SSPE)
e. Susceptibility to chicken pox
462. A small child presents with a low-grade fever, coryza, sore throat, a bright red rash on his cheeks, and a less intense erythematous rash on his body. Elevated IgG and IgM antibody titers to parvovirus suggest a diagnosis of which of the following?
a. Acute Lyme disease
b. Fifth disease
c. Possible hepatitis B infection
d. Possible subacute sclerosing panencephalitis (SSPE)
e. Susceptibility to chicken pox
463. Blood from a woman at a local pregnancy clinic is analyzed for antibody titers to known pathogens. A negative varicella antibody titer in this young woman signifies which of the following?
a. Acute Lyme disease
b. Fifth disease
c. Possible hepatitis B infection
d. Possible subacute sclerosing panencephalitis (SSPE)
e. Susceptibility to chicken pox
464. A patient with severe jaundice and liver failure has an increased antibody titer to delta agent. You should suspect which of the following?
a. Acute Lyme disease
b. Fifth disease
c. Possible hepatitis B infection
d. Possible subacute sclerosing panencephalitis (SSPE)
e. Susceptibility to chicken pox
465. A pediatric patient with progressively developing degenerative neurologic disease/disorder has an elevated CSF antibody titer to measles virus. You should suspect which of the following?
a. Acute Lyme disease
b. Fifth disease
c. Possible hepatitis B infection
d. Possible subacute sclerosing panencephalitis (SSPE)
e. Susceptibility to chicken pox
466. A 2-year-old patient presents to the pediatrician for a routine visit. History and physical examination reveals recurrent infections, and enlarged small blood vessels of the skin and conjunctivas. In addition, the physician notices irregular movements most akin to staggering. Suspecting an immune dysfunction, molecular testing reveals a defect in DNA repair enzymes. This autosomal recessive immune deficiency disorder usually is associated with which of the following?
467. A 10-month-old male infant with recurrent H. influenzae infections presents to the emergency room with otitis media, sinusitis, and in severe respiratory distress. Immunological and genetic testing reveals the absence of B cells and a destructive mutation in the tyrosine kinase gene. This X-linked recessive immune disorder is usually associated with which of the following?
468. Amniocentesis conducted during genetic counseling of a pregnant woman reveals a fetal adenosine deaminase deficiency. This autosomal recessive immunodeficiency is usually associated with which of the following?
469. A young child with spastic paralysis presents to the emergency room. Blood tests reveal hypocalcemia. This immune disorder is usually associated with which of the following?
470. A 10-month-old patient with recurrent pyogenic infections, eczema, and severe bleeding (thrombocytopenia) is diagnosed with Wiskott–Aldrich syndrome. This immune disorder is usually associated with which of the following?
471. An autograft of a burn victim is best described by which one of the following?
a. Transplant from one region of a person to another region
b. Transplant from one person to a genetically identical person
c. Transplant from one species to the same species
d. Transplant from one species to another species
472. Transplantation involving tissue from twin brothers possessing identical HLA genes is best described by which one of the following?
a. Allograft: transplant from one species to the same species
b. Autograft: transplant from one region of a person to another region
c. Isograft: transplant from one person to a genetically identical person
d. Xenograft: transplant from one species to another species
473. A 21-year-old patient in severe kidney failure receives a kidney from his 30-year-old brother. This type of transplantation is best described by which of the following?
a. Allograft: transplant from one species to the same species
b. Autograft: transplant from one region of a person to another region
c. Isograft: transplant from one person to a genetically identical person
d. Xenograft: transplant from one species to another species
474. During the infancy days of cardiac transplantation, nonhuman primate hearts were transplanted into humans to save lives. This type of transplantation is best described by which one of the following?
a. Allograft: transplant from one species to the same species
b. Autograft: transplant from one region of a person to another region
c. Isograft: transplant from one person to a genetically identical person
d. Xenograft: transplant from one species to another species
475. Humoral immunity evaluation mainly consists of measuring the amount of IgG, IgM, and IgA in the patient’s serum. These three immunoglobulins represent three distinct isotypes. An isotype is characterized by which of the following?
a. Determinant exposed after papain cleavage to an F(ab) fragment
b. Determinant from one clone of cells and probably located close to the antigen-binding site of the immunoglobulin
c. Determinant inherited in a Mendelian fashion and recognized by cross-immunization of individuals in a species
d. Heavy-chain determinant recognized by heterologous antisera
e. Species-specific carbohydrate determinant on the heavy chain
476. An allotype is characterized by which of the following?
a. Determinant exposed after papain cleavage to an F(ab) fragment
b. Determinant from one clone of cells and probably located close to the antigen-binding site of the immunoglobulin
c. Determinant inherited in a Mendelian fashion and recognized by cross-immunization of individuals in a species
d. Heavy-chain determinant recognized by heterologous antisera
e. Species-specific carbohydrate determinant on the heavy chain
477. Antibodies produced from hybridomas are extremely useful clinically for their monoclonal properties. These antibodies have the same idio-type. An idiotype is characterized by which of the following?
a. Determinant exposed after papain cleavage to an F(ab’)2 fragment
b. Determinant from one clone of cells and probably located close to the antigen-binding site of the immunoglobulin
c. Determinant inherited in a Mendelian fashion and recognized by cross-immunization of individuals in a species
d. Heavy-chain determinant recognized by heterologous antisera
e. Species-specific carbohydrate determinant on the heavy chain
478. A 30-year-old male presents to the emergency room with difficulty in breathing and abdominal pain. Upon physical examination, you notice diffuse areas of nondependent, nonpitting swelling without pruritus, with predilection for the face, especially the perioral and periorbital areas. You also notice swelling in the mouth, pharynx, and larynx. Laboratory analysis of blood drawn from this patient indicates a complement problem. Which of the following is most likely?
a. High C4, C2, and C3
b. High C1 and normal level of C1 esterase inhibitor
c. High C1 esterase inhibitor and high C4
d. High C1 esterase inhibitor and low C4
e. Low C1 esterase inhibitor and high C4
f. Low C1 esterase inhibitor and low C4
g. Low C4 and high C2
479. A 45-year-old businesswoman arrives in your office with vague abdominal complaints. She has noticed melenic stool. Upon performing a sigmoidoscopy, you find a 4-cm mass in the upper colon. You should immediately order a blood test for which of the following tumor markers?
a. α-Fetoprotein
b. Antitumor antibody
c. Antitumor light chains
d. Carcinoembryonic antigen (CEA)
e. Human chorionic gonadotropin
f. Prostate-specific antigen
Questions 480 and 481
480. An 18-year-old male heroin addict, who practices the sharing of needles at a “shooting gallery,” is positive in the screening test for AIDS. This patient is most likely to be immunodeficient because of which one of the following?
a. A genetic defect in chromosome 14
b. A low T-helper lymphocyte count
c. An atrophied thymus
d. NADPH enzyme deficiency
e. Insufficient B-cell maturation
481. Since a false-positive result is possible in the screening test in the previous vignette, the physician orders a confirmatory test. Which of the following best describes the standard confirmatory test, and what this test checks for, respectively?
a. Complement fixation test; antibodies against the virus
b. Enzyme-linked immunosorbent assay (ELISA); antigens of the virus
c. Radioimmunoassay (RIA); specific antibodies against the virus
d. Western blot; antigens of the virus
e. Western blot; specific antibodies against the virus
482. A pregnant 21-year-old Rh-negative female is about to deliver. The baby’s father is determined to be Rh-positive. To reduce the chance for the development of hemolytic disease of the newborn, which of the following procedures should you order?
a. Administration of anti-Rh antibodies to the fetus postdelivery
b. Administration of anti-Rh antibodies to the mother postdelivery
c. Immediate blood transfusion of the suspected father
d. Immediate blood transfusion of the mother with Rh-positive blood
e. Infusion of immune serum globulin into the fetus
f. Intravenous infusion of the Rh antigen into the mother
Questions 483 and 484
483. An 8-month-old male infant with a history of chronic diarrhea, otitis media, and several episodes of pneumonia presents to your clinic with gingivostomatitis (due to herpes simplex virus) and oral candidiasis (thrush). You immediately order an x-ray and a blood workup. X-ray and laboratory blood analysis reveal the absence of a thymic shadow and absence of B lymphocytes, respectively. History taken from the infant’s mother reveals a rash evident at birth. Which of the following diseases is most likely present in this infant?
a. Ataxia-telangiectasia
b. Bruton agammaglobulinemia
c. Chediak–Higashi syndrome
d. Chronic granulomatous disease
e. Chronic mucocutaneous candidiasis
f. Hereditary angioedema
g. Severe combined immunodeficiency syndrome (SCID)
h. Thymic aplasia (DiGeorge syndrome)
i. Wiskott–Aldrich syndrome
484. Which of the following is the best therapy for the infant in the previous vignette?
a. Antifungal agents
b. Blood transfusion
c. Bone marrow transplant
d. IgG from pooled random donors
e. Immunization with attenuated vaccines
485. A 5-year-old child arrives at the emergency department minutes after being bitten by a black widow spider. You immediately inject gamma globulin in the form of an antivenom. This type of immunization is referred to as which of the following?
a. Artificial active immunization
b. Artificial passive immunization
c. Natural active immunization
d. Natural passive immunization
e. Adoptive immunization
486. A patient with an increased susceptibility to viral, fungal, and protozoa infection would be expected to have a deficiency in which of the following cell types?
a. B lymphocytes
b. Macrophages
c. NK cells
d. Neutrophils
e. T lymphocytes
487. While walking through a field, a 28-year-old woman is stung by a bee. Within 10 minutes, she has asthmatic-like symptoms. This type of hypersensitivity reaction can be correctly characterized by which of the following sequence of steps?
a. Allergen, chemical mediators, sensitization, allergen, IgE, symptoms
b. Allergen, IgE, sensitization, allergen, chemical mediators, symptoms
c. Allergen, sensitization, IgE, allergen, chemical mediators, symptoms
d. Sensitization, allergen, chemical mediators, allergen, IgE, symptoms
e. Sensitization, IgE, allergen, symptoms, allergen, chemical mediators
488. Findings of IgG antibodies to core antigen, antibodies to e antigen, and antibodies to surface antigen in a hepatitis B patient reflects which of the following?
a. Acute infection (incubation period)
b. Acute infection (acute phase)
c. Postinfection (acute phase)
d. Immunization
e. HBV carrier state
489. Findings of HBsAg-positive and HBeAg-positive test results in a hepatitis B patient reflect which of the following?
a. Acute infection (incubation period)
b. Acute infection (acute phase)
c. Postinfection (acute phase)
d. Immunization
e. HBV carrier state
490. Findings of HBsAg positive, HBeAg positive, and IgM core antibody positive in a hepatitis B patient reflect which of the following?
a. Acute infection (incubation period)
b. Acute infection (acute phase)
c. Postinfection (acute phase)
d. Immunization
e. HBV carrier state
491. Findings of HBsAg positive, no antibodies to HBsAg, and other tests variable in a hepatitis B patient reflect which of the following?
a. Acute infection (incubation period)
b. Acute infection (acute phase)
c. Postinfection (acute phase)
d. Immunization
e. HBV carrier state
492. Findings of antibodies to HBsAg in a hepatitis B patient reflect which of the following?
a. Acute infection (incubation period)
b. Acute infection (acute phase)
c. Postinfection (acute phase)
d. Immunization
e. HBV carrier state
493. A 15-year-old male is rushed to the emergency room with a temperature of 103°F, severe headache, and stiff neck. Upon physical examination, a petechial rash is observed all over his body. Suspecting meningitis, the physician orders a lumbar puncture, revealing gram-negative diplococci (Neisseria meningitidis) on Gram stain. The physician wishes to use a more sensitive test to confirm this as the causative agent. Which of the following tests combines features of gel diffusion and immunoelectrophoresis and is applicable only to negatively charged antigens?
a. Coagglutination (COA)
b. Counterimmunoelectrophoresis (CIE)
c. Enzyme-linked immunosorbent assay (ELISA)
d. Latex agglutination (LA)
e. Radioimmunoassay (RIA)
494. A 21-year-old female presents to the emergency room with a high fever, hypotension, and a diffuse, macular, sunburn-like rash that is desquamating. She is also vomiting, has profuse diarrhea, leukocytosis, thrombocytopenia, and elevated BUN and creatinine levels. History from her roommate reveals that these symptoms started soon after the patient began packing her nose to stop chronic nose bleeds. Suspecting S. aureus, a nasal swab specimen is obtained and sent to the laboratory. Which of the following rapid tests will be ordered and depends on the presence of protein A on certain strains of S. aureus?
a. COA
b. CIE
c. ELISA
d. LA
e. RIA
495. A 50-year-old building contractor arrives in your office complaining of abdominal pain that has increased in severity over the past 3 months. He has noticed melenic stool. Ordering a sigmoidoscopy, a 10-cm mass is visualized in the transverse colon. Surgery is immediately done and the tumor excised. As part of the patient’s postsurgical follow through of this resected carcinoma of the colon, blood is obtained and sent to the laboratory to monitor levels of the tumor marker known as CEA. Which of the following tests involves the measurement of very small quantities of CEA through competition of radiolabeled and unlabeled antigen for the same limited amount of antibody?
a. COA
b. CIE
c. ELISA
d. LA
e. RIA
496. A 13-year-old male arrives at his doctor’s office with a severe sore throat and very high fever. On physical examination, the physician observes his pharynx to be inflamed with a significant exudate along with tender cervical lymph nodes. Laboratory tests reveal a leukocytosis. Suspecting Group A β-hemolytic Streptococcus pyogenes, a throat swab and culture are obtained. Using a rapid diagnostic kit recently obtained, the physician decides to test the specimens himself. This test involves inert particles that are sensitized with either antigen or antibody. Which of the following tests is used extensively to detect microbial antigens rapidly (5 minutes or less)?
a. COA
b. CIE
c. ELISA
d. LA
e. RIA
497. A 7-month-old baby who is failing to thrive is brought into a neighborhood clinic. History reveals that the baby’s mother died of AIDS 2 months ago. Blood is obtained and sent to the laboratory to check for HIV infection. The physician orders a test whose detection system is based on enzymatic activity. Which of the following tests is a heterogeneous immunoassay?
a. COA
b. CIE
c. ELISA
d. LA
e. RIA
Questions 498 to 502
A 29-year-old pregnant female gives birth to a stillborn child. History reveals that the woman continued to have close contact with her five cats, by emptying litter boxes and feeding them raw meat, during pregnancy, against her physician’s advice. An autopsy is conducted, and multiple cysts are found in the fetal brain, lungs, liver, and eyes. As a confirmatory test, the pathologist orders an enzyme immunoassay to detect the presence of Toxoplasma gondii. The diagram below presents the various steps (labeled A-F) of the enzyme immunoassay.
498. Failure of or improper methods for which step in the process is the primary cause of high background color?
a. A
b. B
c. C
d. D
e. E
f. F
499. Where is unlabeled antibody attached if this enzyme immunoassay is intended for detection of antigen?
a. A
b. B
c. C
d. D
e. E
f. F
500. What is the location of the “solid phase”?
a. A
b. B
c. C
d. D
e. E
f. F
501. Addition of reagent at which step will cause color in the positive control well and reactive patient specimens?
a. A
b. B
c. C
d. D
e. E
f. F
502. What is the location of the patient’s specimen in the diagram?
a. A
b. B
c. C
d. D
e. E
f. F
503. An 18-year-old male patient with acute lymphocytic leukemia fails all standard chemotherapies. Cells from an HLA-nonidentical donor are used to perform a bone marrow transplant. Prior to transplantation, the patient is given broad-spectrum antibiotics and an immunosuppressive regimen. Within 2 to 4 weeks, lymphocyte and granulocyte numbers begin to rise, confirming bone marrow cell engraftment. However, 1 month later, the patient develops diarrhea, jaundice, and a severe maculopapular rash. Physical examination reveals hepatosplenomegaly. Which of the following is most likely occurring?
a. Acute rejection
b. Chronic rejection
c. Cyclosporine A toxicity
d. Graft versus host disease (GVHD)
e. Hyperacute rejection
504. A 27-year-old male patient (blood group O) arrives at the emergency room with a massive intestinal bleed (hematochezia). Within hours he has lost half of his blood volume, and you decide to transfuse. Due to human error, you transfuse blood group AB into him and within minutes he develops a fever, chills, dyspnea, and a dramatic drop in blood pressure. This reaction is most likely due to which of the following?
a. A cell-mediated response against AB antigens
b. IgG production by the recipient in response to AB antigens
c. Preformed anti-A and anti-B antibodies in the recipient
d. Preformed anti-A and anti-B antibodies of the blood donor
e. Preformed isohemagglutinins of the IgG isotype
505. During a clinic office visit, a 35-year-old male stockbroker shows signs of excessive nervousness and irritability and complains that the office is too hot. History and physical examination reveals the presence of a goiter and exophthalmia. Laboratory analysis of his blood reveals high antibody titers against the thyroid-stimulating hormone (TSH) receptor. Which of the following is the most likely diagnosis?
a. Goodpasture syndrome
b. Graves disease
c. Hashimoto disease
d. Juvenile-onset diabetes mellitus
e. Myasthenia gravis
f. Pernicious anemia
g. Rheumatoid arthritis
h. Systemic lupus erythematosus (SLE)
506. A 9-year-old female with a recent history of weight loss and vision problems arrives at the hospital. Soon after, it is determined that she has low blood glucose, and autoantibodies against β cells are detected in her serum. Which of the following is the most likely diagnosis?
a. Goodpasture syndrome
b. Graves disease
c. Hashimoto disease
d. Juvenile-onset diabetes mellitus
e. Myasthenia gravis
f. Pernicious anemia
g. Rheumatoid arthritis
h. SLE
507. A 35-year-old woman with fever, weight loss, fatigue, and painful joints and muscles presents to her physician’s office. The physician notes that she has marked photosensitivity and a rash on the cheeks and over the bridge of her nose. Laboratory tests reveal anemic conditions and the presence of anti-DNA antibodies. Which of the following is the most likely diagnosis?
a. Goodpasture syndrome
b. Graves disease
c. Hashimoto disease
d. Juvenile-onset diabetes mellitus
e. Myasthenia gravis
f. Pernicious anemia
g. Rheumatoid arthritis
h. SLE
Questions 508 to 512
Diagram depicting the process of T-cell activation by dendritic cells (professional antigen presenting cells, APC). Shown are a CD4 helper T cell (TH), a CD8 cytotoxic T cell (CTL), and dendritic cells (DC). Major histocompatibility complex (MHC) molecules are also shown. CD4 co-receptor is shown for TH cell activation, and CD8 co-receptor is shown for CTL activation. There are 2 zeta chains and 4 CD3 complex molecules (γ, δ, ε, ε). The rectangles associated with zeta and CD3 are the ITAMs. Costimulation, second signal molecules CD28 and B7 are shown for both TH and CTL activation.
508. Which of the following molecules represent the primary or prototypical members involved in signal 2 mediated activation of naïve T cells?
a. CD28, B7-1 or B7-2
b. CTLA-4, CD28, PD-1
c. CTLA-4, B7-1 or B7-2
d. B7-H1, B7-H3, PD-1
509. The following best describes TCR recognition of antigen:
a. Binds to conformational determinants of whole proteins
b. Binds to linear determinants of whole proteins
c. Binds to peptide in the context of MHC
d. Binds to peptide without MHC
e. Binds to large glycoproteins
510. Which of the following best describes the TCR complex?
a. αβ TCR covalently linked with CD3 and ζ chains
b. αβ TCR covalently linked with CD2 and CD28
c. αβ TCR noncovalently associated with CD3 and ζ chains
d. αβ TCR noncovalently associated with CD2 and CD28
e. αα TCR noncovalently associated with CD3 and ζ chains
511. The membrane associated T-lymphocyte antigen receptor or TCR is best described asa:
a. Heterodimer consisting of covalently linked α and β chains
b. Homodimer consisting of covalently linked α and β chains
c. Homodimer associated with Igα and Igβ
d. Monomer associated with Igα and Igβ
e. Heavy chain monomer associated with β2m
512. Nearly 95% of mature T cells possess a T-cell receptor (TCR) complex that contains:
a. Igβ and Igα
b. CD28 and TCR γδ
c. A highly variable antigen coreceptor and TCR γδ
d. Four CD3 molecules (γ, δ, ε, ε), each covalently linked to the TCR αβ heterodimer
e. Invariable ζ chain homodimer noncovalently associated with the TCR αβ heterodimer
513. A preschool boy is diagnosed with an immunodeficiency characterized by impaired T-cell activation. The defect is caused by a genetic alteration of a membrane protein whose cytoplasmic tail is involved in signaling associated with TCR recognition of peptide antigen in the context of MHC. Which of the following proteins does NOT fit this description?
a. CD3γ
b. ζ chain
c. TCRβ
d. CD4
e. CD8
514. The germline antigen receptor loci for both alpha and beta chains of the TCR are found in:
a. All nucleated cells
b. Double positive T cells only
c. Naïve CD4+ T cells only
d. Naïve CD8+ T cells only
e. Pre-T cells only
515. The processes of negative selection for T lymphocytes eliminates those T cells with TCRs that
a. Do not recognize self-peptide/self-MHC
b. Recognize foreign-peptide/self-MHC complexes with low avidity/affinity
c. Recognize foreign-peptide/self-MHC complexes with high avidity/affinity
d. Recognize self-peptide/self-MHC complexes with low avidity/affinity
e. Recognize self-peptide/self-MHC complexes with high avidity/affinity
516. Cells of the immune system arise in the bone marrow. The cell that finishes its maturation in the thymus is the
a. Follicular B-2 B lymphocyte
b. Marginal zone B lymphocyte
c. NK cell
d. αβ T lymphocyte
e. Dendritic cell
517. A 1-month-old infant with a bright red rash and purulent conjunctivitis is admitted to the hospital. Examination revealed eosinophilia, low lymphocyte count, and no thymic shadow. Lymphnodes were enlarged and opportunistic infections noted. The diagnosis was a form of SCID termed Omenn syndrome, an autosomal recessive form of SCID. Mutations in which of the following would explain this disease?
a. MHC class I
b. MHC class II
c. CD3 or TCR αβ
d. RAG-1 or RAG-2
e. CD4 or CD8
518. Class-I MHC-restricted CD8+ T cell (CTL) responses to tumors can be demonstrated in patients with various types of tumors, yet most of these tumors do not express costimulatory molecules. Which mechanism most likely explains how naïve CD8+ T cells specific for antigens expressed by these tumors are activated and differentiate into CTLs?
a. Tumor secretion of TGF-β
b. Tumor secretion of IL-12
c. Tumor expression of B7
d. Direct priming of the CTLs
e. Cross priming of the CTLs
519. A 47-year-old woman had a mastectomy because she had breast carcinoma that was previously diagnosed by biopsy. Pathologic examination revealed that several axillary lymph nodes contained metastatic tumors. A test was performed on the tumor cells extracted from the mastectomy specimen, which indicated that the tumor cells overexpressed a certain cellular proto-oncogene. On the basis of this test result, the patient was treated with an FDA-approved monoclonal antibody specific for the protein encoded by that gene. Which of the following was most likely the protein target of the FDA-approved passive antibody therapy?
a. HPV E6, E7
b. Her2/Neu
c. CA-125
d. CD20
e. CEA
520. Which of the following does not describe a documented mechanism of tumor-mediated immune evasion?
a. Down regulation of class I MHC
b. Secretion of TGF-β
c. Secretion of decoy molecules
d. Antigenic variation
521. Which of the following best describes the mechanism(s) of action of CTLA-4?
a. Signal 1 and costimulation
b. Competition and inhibition
c. Activation and proliferation
d. ZAP-70 and ITAMs
e. PD-1 and PD-L1
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