Success! In Clinical Laboratory Science- Immunology

1. Color Plate 21■ depicts a monomeric im-munoglobulin molecule. The portion of the molecule indicated by the dotted red circle and the red arrow is called the

A. Fab fragment

B. Fc fragment

C. Heavy chain

D. Hinge region

A. Fab fragment

2. A hapten is

A. Half of an immunoglobulin molecule

B. A carrier molecule for an antigen that is not antigenic alone

C. An immunoglobulin functional only in the presence of complement

D. A determinant capable of stimulating an immune response only when bound to a carrier

D. A determinant capable of stimulating an immune response only when bound to a carrier

3. Which of the following is characteristic of B cells?

A. Phagocytic

B. Participate in antibody-dependent cel-lular cytotoxicity (ADCC) reactions

C. Contain surface immunoglobulins

D. Secrete the C5 component of comple-men

C. Contain surface immunoglobulins

4. A lymphokine is

A. A soluble mediator produced by granu-locytes and affecting lymphocytes

B. A soluble mediator produced by lym-phocytes

C. A soluble mediator produced by plasma cells

D. A molecule secreted by bacteria that lyses lymphocytes

B. A soluble mediator produced by lym-phocytes

5. For an antibody-coated antigen to be phagocytized by a monocyte or macro-phage, what part of the antibody molecule binds to a receptor on the phagocytic cell?

A. Fc region

B. Fab region

C. Hinge region

D. Variable region

A. Fc region

6. Cell-mediated immunity is primarily medi-ated by

A. B cells

B. T-helper cells

C. Plasma cells

D. Dendritic cells

B. T-helper cells

7. Molecules that require T-helper cells to stimulate antibody formation

A. Antigen

B. Epitope

C. Thymic-dependent immunogen

D. Thymic-independent immunogen

C. Thymic-dependent immunogen

8. Human leukocyte antigens (HLAs) are found on

A. All nucleated cells

B. Red blood cells only

C. Solid tissue only

D. White blood cells only

A. All nucleated cells

9. Which of the following is more likely to be diagnostic of an acute infection?

A. A total acute antibody titer of 2 fol-lowed by a convalescent titer of 16

B. A total acute antibody titer of 80 fol-lowed by a convalescent titer of 40

C. A total antibody titer of 80

D. An IgG antibody titer of 8

A. A total acute antibody titer of 2 fol-lowed

10. A young woman shows increased suscepti-bility to pyogenic infections. Upon testing, she shows a low level of C3. Which of the following statements is probably true?

A. She has an autoimmune disease with continual antigen-antibody activity caus-ing consumption of C3.

B. She has DiGeorge syndrome.

C. She has decreased production of C3.

D. She may produce an inactive form of C2, a precursor of C3

C. She has decreased production of C3.

11. What is the predominant type of antibody found in the serum of neonates born after full-term gestation?

A. Infant IgA

B. Infant IgG

C. Infant IgM

D. Maternal IgG

C. Infant IgM

12. An important part of the nonspecific im-mune response is(are)

A. B cells

B. Dendritic cells

C. Polymorphonuclear cells (PMNs)

D. Cytotoxic T lymphocytes (CTLs)

C. Polymorphonuclear cells (PMNs)

13. The major class of immunoglobulin found in adult human serum is

A. IgA

B. IgE

C. IgG

D. IgM

C. IgG

14. Which class of immunoglobulin possesses delta heavy chains?

A. IgA

B. IgD

C. IgE

D. IgG

B. IgD

15. Which class of immunoglobulin possesses 10 antigenic binding sites?

A. IgA

B. IgD

C. IgG

D. IgM

D. IgM

16. Color Plate 22■ represents a dimeric IgA molecule. The structure printed in red and indicated by the red arrow is called the

A. J-piece

B. Hinge region

C. Heavy chain

D. Light chain

A. J-piece

17. Which class of immunoglobulin binds to basophils and mast cells to mediate imme-diate hypersensitivity reactions?

A. IgA

B. IgD

C. IgE

D. IgG

C. IgE

18. Type I hypersensitivity is

A. Associated with complement-mediated cell lysis

B. Due to immune complex deposition

C. Mediated by activated macrophages

D. An immediate allergic reaction

D. An immediate allergic reaction

19. Elevated antithyroglobulin and antithyroid peroxidase are suggestive of

A. Graves disease

B. Hashimoto disease

C. Myasthenia gravis

D. Multiple sclerosis

B. Hashimoto disease

20. Severe combined immunodeficiency (SCID) is an

A. Immunodeficiency with decreased B cells and neutrophils

B. Immunodeficiency with lymphocytope-nia and eosinophilia

C. Immunodeficiency with decreased or dysfunctional T and B cells

D. Immunodeficiency with decreased lymphocytes and decreased complement concentratio

C. Immunodeficiency with decreased or dysfunctional T and B cells

21. An example of immune injury due to the deposition of antigen-antibody complexes is A. Acute glomerulonephritis

B. Bee-sting allergy

C. Contact dermatitis

D. Penicillin allergy

A. Acute glomerulonephritis

22. The serologically detectable antibody produced in rheumatoid arthritis (RA) is primarily of the class

A. IgA

B. IgE

C. IgG

D. IgM

D. IgM

23. In bone marrow transplantation, immuno-competent cells in the donor marrow may recognize antigens in the recipient and re-spond to those antigens. This phenomenon is an example of

A. Acute rejection

B. Chronic rejection

C. Graft-versus-host disease

D. Hyperacute rejection

C. Graft-versus-host disease

24. Multiple myeloma is a

A. Lymphoproliferative disease of T cells

B. Cancer of plasma cells characterized by increased antibody concentration

C. Lymphoproliferative disease resulting in a decrease in antibody production

D. Cancer of monocytes characterized by increased kappa and lambda chain synthesis

B. Cancer of plasma cells characterized by increased antibody concentration

25. Which one of the following describes a direct immunofluorescent assay?

A. Conjugated reagent antigen reacts with antibodies to form antigen-antibody complexes.

B. Antigens react with unlabeled antibody-forming antigen-antibody complexes that attach to labeled antibodies.

C. A dye is attached to a molecule, and it reacts with an immune complex to produce a color.

D. Conjugated reagent antibody reacts with antigen to form antigen-antibody complexes

D. Conjugated reagent antibody reacts with antigen to form antigen-antibody complexes

26. In individuals allergic to pollen, hyposensi-tization protocols may be initiated. These individuals receive injections of

A. Allergen

B. Pooled human antisera

C. Monoclonal antibody directed against human T cells

D. Monoclonal antibody directed against human B cell

A. Allergen

27. After exposure to antigen, the first antibod-ies that can be detected belong to the class

A. IgA

B. IgE

C. IgG

D. IgM

D. IgM

28. Corneal tissue may be transplanted success-fully from one patient to another because

A. The cornea is nonantigenic

B. Corneal antigens do not activate T cells

C. Anticorneal antibodies are easily sup-pressed

D. The cornea occupies a privileged site not usually seen by the immune system

D. The cornea occupies a privileged site not usually seen by the immune system

29. A kidney transplant from one identical twin to another is an example of a(n)

A. Allograft

B. Autograft

C. Isograft

D. Xenograft

C. Isograft

30. In Bruton disease, measurement of serum immunoglobulins would show

A. Elevated levels of IgE

B. Elevated levels of IgG

C. Normal levels of IgG and IgM but reduced levels of IgA

D. The absence of all immunoglobulins

D. The absence of all immunoglobulins

31. Diagnosis of group A streptococci (Strepto-coccus pyogenes) infection is indicated by the presence of

A. Anti-protein A

B. Anti-DNase B

C. Anti-beta-toxin

D. C-reactive protein (CRP)

B. Anti-DNase B

32. A molecule found in human serum some-times used as a tumor marker is

A. Alpha-fetoprotein (AFP)

B. HBsAg

C. Biotin

D. CD1

A. Alpha-fetoprotein (AFP)

33. Which cell is the principal source of inter-leukin 2?

A. B cell

B. T cell

C. Monocyte

D. Plasma cell

B. T cell

34. The most specific and sensitive test for the diagnosis of celiac disease

A. Anti-transglutaminase 2 (TG2) antibody

B. Anti-acetylcholine receptor antibody

C. Anti-Smith antibody

D. Isolation of T cells reactive to pancre-atic antigens

A. Anti-transglutaminase 2 (TG2) antibody

35. A major advantage of passive immuniza-tion compared to active immunization is that A. Antibody is available more quickly

B. Antibody persists for the life of the recipient C. IgM is the predominant antibody class provided

D. Oral administration can be use

A. Antibody is available more quickly

36. The strength with which a multivalent anti-body binds a multivalent antigen is termed the A. Affinity

B. Avidity

C. Reactivity

D. Valence

B. Avidity

37. How does the secondary humoral immune response differ from the primary response?

A. The lag phase (the time between ex-posure to immunogen and production of antibody) is longer in the secondary immune response.

B. IgM is the predominant antibody class produced in the secondary immune response. C. The antibody levels produced are higher in the secondary immune response.

D. Cytotoxic T lymphocytes play an impor-tant role in the secondary response.

C. The antibody levels produced are higher in the secondary immune response.

38. You would expect patients suffering from selective IgA deficiency to present with

A. Food allergies

B. Septicemias

C. Recurrent yeast infections

D. Recurrent respiratory tract infections

D. Recurrent respiratory tract infections

39. The type of immunity that follows the injection of an immunogen is termed

A. Artificial active

B. Natural active

C. Artificial passive

D. Innate

A. Artificial active

40. Patients born with an adenosine deaminase deficiency would likely suffer from A. Acquired immunodeficiency syndrome (AIDS)

B. DiGeorge syndrome

C. Severe combined immunodeficiency

D. Wiskott-Aldrich syndrome

C. Severe combined immunodeficiency

41. Innate immunity includes

A. Anamnestic response

B. Antibody production

C. Cytotoxic T cell activity

D. Phagocytosis by polymorphonuclear cells

D. Phagocytosis by polymorphonuclear cells

42. The agglutination pattern shown in Color Plate 23■ was observed while performing an antibody titration. This agglutination pattern is an example of

A. A prezone reaction

B. A prozone reaction

C. A postzone reaction

D. Incomplete complement inactivation

B. A prozone reaction

43. The antibody most frequently present in systemic lupus erythematosus is directed against

A. Surface antigens of bone marrow stem cells

B. Surface antigens of renal cells

C. Nuclear antigen

D. Myelin

C. Nuclear antigen

44. The rapid plasma reagin (RPR) assay for syphilis does not need to be read micro-scopically because the antigen is

A. Cardiolipin

B. Complexed with latex

C. Complexed with charcoal

D. Inactivated bacterial cells

C. Complexed with charcoal

45. The Venereal Disease Research Laboratory (VDRL) test for syphilis is classified as a(n)

A. Agglutination reaction

B. Flocculation reaction

C. Hemagglutination reaction

D. Precipitation reaction

B. Flocculation reaction

46. One cause of a false-positive VDRL test is A. Brucellosis

B. Treponema pallidum infection

C. Rocky Mountain spotted fever

D. Systemic lupus erythematosus

D. Systemic lupus erythematosus

47. The portion of an antigen that binds to an antibody or T-cell receptor is called a(n)

A. Allergin

B. Avidin .

C. Epitope

D. Valence

C. Epitope

48. Identical antibodies produced from a single clone of plasma cells describes

A. Reagin

B. Cold agglutinins

C. Heterophile antibodies

D. Monoclonal antibodies

D. Monoclonal antibodies

49. A 65-year-old male presents with a frac-tured wrist and complains of bone pain.A bone marrow aspirate reveals a large num-ber of plasma cells. You should suspect

A. A traumatic bone marrow aspirate col-lection

B. Multiple myeloma

C. Bare lymphocyte syndrome

D. Hyper-IgM syndrome

B. Multiple myeloma

50. What is the advantage of using immunoflu-oresence testing to diagnose systemic lupus erythematosus?

A. High specificity

B. Can identify staining patterns

C. Does not require positive control

D. Easy to interpret

B. Can identify staining patterns

51. The Fab portion of an antibody

A. Binds T-cell receptor

B. Consists of two light chains only

C. Consists of two heavy chains only

D. Contains the hypervariable region

D. Contains the hypervariable region

52. In the enzyme-linked immunosorbent assay (ELISA), the visible reaction is due to a reaction between

A. Enzyme and antibody

B. Enzyme and substrate

C. Fluorescent dye and antigen

D. Latex particles and antibody

B. Enzyme and substrate

53. Elevated IgE levels are typically found in

A. Type I hypersensitivity reactions

B. Type II hypersensitivity reactions

C. Type III hypersensitivity reactions

D. Type IV hypersensitivity reactions

A. Type I hypersensitivity reactions

54. Loss of self-tolerance results in

A. Autoimmune disease

B. Graft-versus-host disease

C. Immunodeficiency

D. Tumors

A. Autoimmune disease

55. A human cell with CD8 on its surface is most likely a

A. B cell

B. Monocyte

C. T-helper cell

D. Cytotoxic T cell

D. Cytotoxic T cell

56. Which of the following statements about immunoglobulin light chains is true?

A. Each immunoglobulin monomer has either one kappa or one lambda chain.

B. There are two types: kappa and lambda.

C. They consist of constant regions only.

D. They form part of the Fc fragment.

B. There are two types: kappa and lambda.

57. Which of the following statements applies to the Fc fragment of an immunoglobulin molecule?

A. It consists of the entire heavy chain.

B. It contains the variable region of the heavy chain.

C. It contains the antigen binding sites of the molecule.

D. It is the region of the molecule that binds to receptors on various white blood cells.

D. It is the region of the molecule that binds to receptors on various white blood cells.

58. Monoclonal antibodies are produced by

A. Cultured T cells

B. Human plasma cells

C. Mouse plasma cells

D. Hybridomas

D. Hybridomas

Antibodies that bind to the same epitope are of the same

A. Allotype

B. Autotype

C. Idiotype

D. Isotype

C. Idiotype

60. Skin testing is a useful diagnostic tool in a number of disorders, such as tuberculosis. Which of the following statements about skin testing is true?

A. A positive test depends on preformed antibody.

B. Reactivity to a particular antigen may be transferred from one individual to another by sensitized lymphocytes.

C. The intensity of the response correlates directly with the clinical activity of the disease

D. The maximum response will occur im-mediately.

B. Reactivity to a particular antigen may be transferred from one individual to another by sensitized lymphocytes.

61. The activity of natural killer (NK) cells

A. Does not require previous exposure to an antigen

B. Involves phagocytosis and killing of bacteria

C. Requires interaction with cytotoxic T cells

D. Requires interaction with B cells

A. Does not require previous exposure to an antigen

62. Interaction between B-and T-helper cells involves

A. MHC II molecule on B cell binding to MHC I molecule on the T cell

B. MHC II molecule on B cell binding to CD3 on the T cell

C. Foreign antigen on B cell binding to T-cell receptor

D. CD3 molecule on B cell binding to T-cell receptor

C. Foreign antigen on B cell binding to T-cell receptor

63. Which of the following is a characteristic of T cells?

A. Synthesize antibody

B. Mature in the thymus

C. Able to bind unprocessed antigen

D. Primarily protect against extracellular parasites

B. Mature in the thymus

64. The primary mechanism responsible for pa-thology in systemic lupus erythematosus is A. Allergic reaction to foreign molecules

B. Antibodies directed against self anti-gens

C. Polyclonal activation of cytotoxic T cells

D. Lack of intracellular killing after neutro-phil phagocytosis of bacteria

B. Antibodies directed against self anti-gens

65. In the complement system

A. A C3 deficiency would likely be asymp-tomatic

B. Antibody is required for the activation of the lectin pathway

C. C3b is an important opsonin

D. C9 initiates the membrane attack com-plex

C. C3b is an important opsonin

66. An autoimmune disease causing destruc-tion of pancreatic cells can result in

A. Hashimoto disease

B. Multiple sclerosis

C. Myasthenia gravis

D. Type 1 diabetes

D. Type 1 diabetes

67. Two unrelated individuals receive the sea-sonal influenza vaccine. You would expect the two individuals to create antibodies to the immunogens in the vaccine of the same

A. Allotype

B. Autotype

C. Heterotype

D. Isotype

D. Isotype

68. NK cells target altered host cells, such as tumor cells, based on

A. Altered MHC I molecules on target cell

B. Altered CD4 molecule on target cell

C. Interleukin 3 released by target cell

D. Complement proteins attached to target cell

A. Altered MHC I molecules on target cell

69. Which of the following complement proteins is part of the membrane attack complex?

A. C1

B. C3

C. C4

D. C5

D. C5

70. Which of the following is characteristic of contact dermatitis?

A. Caused by preformed IgE antibody

B. Characterized by infiltration of neutro-phils into the site of the reaction

C. The primary symptoms often occur in the respiratory tract.

D. Usually due to a hapten

D. Usually due to a hapten

71. Which of the following statements about the test for C-reactive protein (CRP) is true?

A. It correlates with neutrophil phagocytic function.

B. It is an indicator of ongoing inflamma-tion. C. It is diagnostic for rheumatic fever.

D. Levels decrease during heart disease.

B. It is an indicator of ongoing inflamma-tion.

72. In the complement classical pathway,

A. C3 is activated by binding C-reactive protein

B. The sequence of activation is C1, C2, C3, C4 C. C1q is activated by the presence of a single Fab region

D. Activation by antibody requires one IgM or two IgG molecule

D. Activation by antibody requires one IgM or two IgG molecule

73. The alternative complement pathway

A. Can be activated by bacterial capsule polysaccharides

B. Uses C5b as a C3 convertase

C. Bypasses steps C3 through C5 of the classical pathway

D. Is inactivated by properdin

A. Can be activated by bacterial capsule polysaccharides

74. A cut on a person's finger becomes con-taminated with the bacterium Staphylococcus aureus. The first response by the immune system consists of activity of

A. B cells

B. Monocytes

C. Neutrophils

D. T cells

C. Neutrophils

75. Incompatible blood transfusions are ex-amples of

A. Type I hypersensitivity reactions

B. Type II hypersensitivity reactions

C. Type III hypersensitivity reactions

D. Type IV hypersensitivity reactions

B. Type II hypersensitivity reactions

76. A soluble antigen and soluble antibody reacting to form an insoluble product de-scribes A. Agglutination reactions

B. Heterophile reactions

C. Labeled reactions

D. Precipitation reactions

D. Precipitation reactions

77. Which of the following is an example of a treponemal antigen test used for the diag-nosis of syphilis?

A. CRP

B. RPR

C. VDRL

D. TP-PA

D. TP-PA

78. A serum sample is positive for HBsAg. This result indicates that the person from whom the serum was taken

A. Had a hepatitis B infection in the past but overcame the infection

B. Has either active or chronic hepatitis B infection

C. Was immunized recently against the hepatitis B virus (HBV)

D. Is not infectious for the HBV

B. Has either active or chronic hepatitis B infection

79. After adding sensitized sheep red blood cells in the complement fixation test, it is noted that all of the tubes exhibit hemoly-sis. What does this indicate?

A. The patient serum was not heat inacti-vated.

B. The sensitized red blood cells were unstable.

C. The incubation temperature was too low.

D. The patient serum lacked antibodies to the antigen in question

D. The patient serum lacked antibodies to the antigen in question

80. The isotype of an immunoglobulin anti-body

A. Is defined by the heavy chain

B. Is defined as different alleles of the same antibody type (e.g., IgG)

C. Is constant for all immunoglobulins of an individual

D. Is the variation within the variable region

A. Is defined by the heavy chain

81. A patient report states the presence of se-rum antibodies to OspC. What disease does the patient most likely have?

A. Syphilis

B. Strep throat

C. Lyme disease

D. Rubella

C. Lyme disease

82. Identification of cells based on membrane molecules by flow cytometry involves

A. Fluorescent-labeled antibody

B. Enzyme-labeled antibody

C. Peripheral blood cells first separated by Ficoll-Paque

D. Complement proteins attaching to target cell

A. Fluorescent-labeled antibody

83. Hashimoto disease is an autoimmune dis-ease primarily involving the

A. Kidneys

B. Liver

C. Lungs

D. Thyroid gland

D. Thyroid gland

84. Rheumatic fever sometimes occurs after group A streptococcal infections. In this condition, an autoimmune response attacks the endocardium and heart valves. This phenomenon is an example of

A. Epitope spreading

B. Molecular mimicry

C. Polyclonal B cell activation

D. Preferential activation of T-helper cells

B. Molecular mimicry

85. "Superantigens" are toxins produced by some strains of Staphylococcus aureus and group A streptococci and cause damage by

A. Molecular mimicry

B. Polyclonal T cell activation

C. Lysing white blood cells and platelets

D. Lysing red blood cells

B. Polyclonal T cell activation

86. The first serologic marker to appear in patients with acute hepatitis B virus infec-tion is

A. Anti-HB

B. Anti-HBc

C. Anti-HBe

D. HBsAg

D. HBsAg

87. A living donor is being sought for a child who requires a kidney transplant. The best odds of finding an MHC-compatible donor occur between the child and

A. A sibling (brother or sister)

B. An unrelated individual

C. The child's father

D. The child's mother

A. A sibling (brother or sister)

88. Cells that can act as antigen-presenting cells for exogenous antigens include

A. All nucleated cells

B. Endothelial cells

C. B lymphocytes

D. T lymphocytes

C. B lymphocytes

89. In patients with human immunodeficiency virus (HIV) infection, immune status can be monitored by measuring the ratio of

A. CD3 + cells to CD8 + cells

B. CD4 + cells to CD8 + cells

C. Lymphocytes to monocytes

D. T cells to B cells

B. CD4 + cells to CD8 + cells

90. Why does vaccination against hepatitis B virus (HBV) also prevent hepatitis D virus (HDV) infections?

A. An immunogen from HBV in the vac-cine is also associated with HDV.

B. The HBV vaccine induces formation of heterophile antibodies that cross-react with HDV.

C. The HBV vaccine stimulates liver cells to produce antiviral molecules active against all hepatitis viruses.

D. HDV requires the host to be concur-rently infected with HBV.

D. HDV requires the host to be concur-rently infected with HBV.

91. B lymphocytes and T lymphocytes are derived from

A. Hematopoietic stem cells

B. Macrophages or monocytes

C. Mucosa-associated lymphoid tissue

D. The fetal liver

A. Hematopoietic stem cells

92. A patient with suspected human immu-nodeficiency virus (HIV) infection has a reactive screening test. The secondary tests for anti-HIV-1 and anti-HIV-2 are both nonreactive. Which one of the following should be done?

A. Repeat testing in 3 months

B. Perform a western blot on the present sample

C. Perform an HIV nucleic acid amplifica-tion test on the present sample

D. Notify the primary care provider that the patient has an HIV infection

C. Perform an HIV nucleic acid amplifica-tion test on the present sample

93. The primary target of human immunodefi-ciency virus

A. B cells

B. Pre-T cells

C. CD4+ T cells

D. CD8+ T cells

C. CD4+ T cells

94. An antibody titration is depicted in Color Plate 24■. In this titration, a 0.2 mL aliquot of a patient's serum sample was added to 0.8 mL of saline, and this mixture was placed into tube #1. A 0.5 mL sample was removed from tube #1 and placed into tube #2, containing 0.5 mL of saline. This procedure was repeated through tube #10. The dilutions were assayed for antibody to an infectious agent. How should the anti-body titer be reported?

A. 256

B. 512

C. 640

D. 1280

C. 640

95. In a chemiluminescent immunologic assay, what is the signal detected?

A. Light

B. An electric signal

C. A purple-colored compound

D. A yellow-colored compound

A. Light

96. A 28-year-old female complains to her family physician of abdominal pain, loss of appetite, and low-grade fever. Physical examination reveals abdominal tenderness and a low-grade fever. Her physician orders a hepatitis profile and obtains the results below.

Anti-HBc, HBsAg, HBeAg reactive Anti-HBs non reactive

Which of the following is the most likely conclusion?

A. Acute HAV infection

B. Acute HBV infection

C. Chronic HBV infection

D. Immunity to HBV due to past infection

C. Chronic HBV infection

97. An 11-year-old female presents with fever, sore throat, lethargy, and tender cervi-cal lymphadenopathy. Relevant findings include splenomegaly and lymphocytosis, with many reactive lymphocytes. A hetero-phile antibody test was negative. Further laboratory results were as follows:

CMV titer IgG-20 IgM-0

EBV titer IgG0 IgM-80

What conclusion can be made concerning the diagnosis?

A. Acute CMV infection

B. Acute EBV infection

C. Chronic CMV infection

D. Chronic EBV infection

B. Acute EBV infection

98. A male infant had been well until about 5 months of age, at which time he was diagnosed as having otitis media and bron-chitis and was treated empirically. Over the next several months he presented with streptococcal pneumonia several times. At 10 months of age, a serum protein electro-phoresis showed a virtual lack of gamma globulins. Quantitative serum levels were as follows: 75 mg/dL IgG and undetectable levels of IgM, IgA, and IgE. There were a normal number of T cells, and they exhib-ited normal mitogen stimulation. What disease does this child most likely suf-fer from?

A. Combined immunodeficiency

B. DiGeorge syndrome

C. Iatrogenic immunodeficiency

D. X-linked agammaglobulinemia

D. X-linked agammaglobulinemia

99. A 33-year-old female presents to her prima-ry care provider complaining of increased sweating and palpitations over a 3-month period. She has also lost 15 pounds. Ex-amination reveals a swollen thyroid gland. Thyroid study reveals T3 of 4.8 nmol/L (reference range 0.8-2.4 nmol/L), T4 of 48 nmol/L (reference range 9-23 nmol/L), and thyroid-stimulating hormone 0.4 mU/L (reference range 0.4-5 mU/L). The patient likely has

A. Hashimoto disease

B. Addison disease

C. Circulating antibodies to thyroid peroxi-dase

D. Pituitary gland hyperactivity

C. Circulating antibodies to thyroid peroxi-dase