IMMUNOSERO

Color Plate 21 depicts a monomeric immunoglobulin 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

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

Which of the following is characteristic of B cells?

A. Phagocytic

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

C. Contain surface immunoglobulin

D. Secrete the C5 component of complement

C. Contain surface immunoglobulin

A lymphokine is

A. A soluble mediator produced by granulocytes and affecting lymphocytes

B. A soluble mediator produced by lymphocytes

C. A soluble mediator produced by plasma cells

D. A molecule secreted by bacteria that lyses lymphocytes

B. A soluble mediator produced by lymphocytes

For an antibody-coated antigen to be phagocytized by a monocyte or macrophage, 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

Cell-mediated immunity is primarily mediated by

A. B cells

B. T-helper cells

C. Plasma cells

D. Dendritic cells

B. T-helper cells

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

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

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

A. A total acute antibody titer of 2 followed by a convalescent titer of 16

B. A total acute antibody titer of 80 followed by a convalescent titer of 40

C. A total antibody titer of 80

D. An IgG antibody titer of 80

A. A total acute antibody titer of 2 followed by a convalescent titer of 16

A young woman shows increased susceptibility 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 causing 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

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

D. Maternal IgG

An important part of nonspecific immune response is (are)

A. B cells

B. Dendritic cells

C. Polymorphonuclear cells (PMNs)

D. Cytotoxic T lymphocytes (CTLs)

C. Polymorphonuclear cells (PMNs)

The major class of immunoglobulin found in adult human serum is

A. IgA

B. IgE

C. IgG

D. IgM

C. IgG

Which class of immunoglobulin possesses delta heavy chains?

A. IgA

B. IgD

C. IgE

D. IgG

B. IgD

Which class of immunoglobulin possesses 10 antigenic binding sites?

A. IgA

B. IgD

C. IgG

D. IgM

D. IgM

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

Which class of immunoglobulin binds to basophils and mast cells to mediate immediate hypersensitivity reactions?

A. IgA

B. IgD

C. IgE

D. IgG

C. IgE

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

Elevated antithyroglobulin and antithyroid peroxidase are suggestive of

A. Graves disease

B. Hashimoto disease

C. Myasthenia gravis

D. Multiple sclerosis

B. Hashimoto disease

Severe combined immunodeficiency (SCID) is an

A. Immunodeficiency with decreased B cells and neutrophils

B. Immunodeficiency with lymphocytopenia and eosinophilia

C. Immunodeficiency with decreased or dysfunctional T and B cells

D. Immunodeficiency with decreased lymphocytes and decreased complement concentration

C. Immunodeficiency with decreased or dysfunctional T and B cells

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

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

A. IgA

B. IgE

C. IgG

D. IgM

D. IgM

In bone marrow transplantation, immuno-competent cells in the donor marrow may recognize antigens in the recipient and respond 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

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

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.

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 cells

A. Allergen

After exposure to antigen, the first antibodies that can be detected belong to the class

A. IgA

B. IgE

C. IgG

D. IgM

D. IgM

Corneal tissue may be transplanted successfully from one patient to another because

A. The cornea is nonantigenic

B. Corneal antigens do not activate T cells

C. Anticorneal antibodies are easily suppressed

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

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

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

Diagnosis of group A streptococci (Streptococcus 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

A molecule found in human serum sometimes used as a tumor marker is

A. Alpha-fetoprotein (AFP)

B. HBsAg

C. Biotin

D. CD1

A. Alpha-fetoprotein (AFP)

Which cell is the principal source of interleukin 2?

A. B cell

B. T cell

C. Monocyte

D. Plasma cell

B. T cell

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 pancreatic antigens

A. Anti-transglutaminase 2 (TG2) antibody

A major advantage of passive immunization 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 used

A. Antibody is available more quickly

The strength with which a multivalent antibody binds a multivalent antigen is termed the

A. Affinity

B. Avidity

C. Reactivity

D. Valence

B. Avidity

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

A. The lag phase (the time between exposure 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 important role in the secondary response

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

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

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

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

Innate immunity includes

A. Anamnestic response

B. Antibody production

C. Cytotoxic T cell activity

D. Phagocytosis by polymorphonuclear cells

D. Phagocytosis by polymorphonuclear cells

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

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

The rapid plasma reagin (RPR) assay for syphilis does not need to be read microscopically because the antigen is

A. Cardiolipin

B. Complexed with latex

C. Complexed with charcoal

D. Inactivated bacterial cells

C. Complexed with charcoal

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

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

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

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

A 65-year-old male presents with a fractured wrist and complains of bone pain. A bone marrow aspirate reveals a large number of plasma cells. You should suspect

A. A traumatic bone marrow aspirate collection

B. Multiple myeloma

C. Bare lymphocyte syndrome

D. Hyper-IgM syndrome

B. Multiple myeloma

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

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

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

Elevated IgE levels are typically found in

A. Type I hypersensitivity reactions

B. Type Il hypersensitivity reactions

C. Type III hypersensitivity reactions

D. Type IV hypersensitivity reactions

A. Type I hypersensitivity reactions

Loss of self-tolerance results in

A. Autoimmune disease

B. Graft-versus-host disease

C. Immunodeficiency

D. Tumors

A. Autoimmune disease

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

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.

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.

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

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.

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

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 I-cell receptor

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

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

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

The primary mechanism responsible for pathology in systemic lupus erythematosus is

A. Allergic reaction to foreign molecules

B. Antibodies directed against self antigens

C. Polyclonal activation of cytotoxic T cells

D. Lack of intracellular killing after neutrophil phagocytosis of bacteria

B. Antibodies directed against self antigens

In the complement system

A. A C3 deficiency would likely be asymptomatic

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

C. C3b is an important opsonin

D. C9 initiates the membrane attack complex

C. C3b is an important opsonin

An autoimmune disease causing destruction of pancreatic cells can result in

A. Hashimoto disease

B. Multiple sclerosis

C. Myasthenia gravis

D. Type 1 diabetes

D. Type 1 diabetes

Two unrelated individuals receive the seasonal 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

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

A. Altered MHC 1 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 1 molecules on target cell

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

A. C1

B. C3

C. C4

D. C5

D. C5

Which of the following is characteristic of contact dermatitis?

A. Caused by preformed IgE antibody

B. Characterized by infiltration of neutrophils 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

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 inflammation.

C. It is diagnostic for rheumatic fever.

D. Levels decrease during heart disease.

B. It is an indicator of ongoing inflammation.

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 molecules

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

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

A cut on a person's finger becomes contaminated 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

Incompatible blood transfusions are examples of

A. Type I hypersensitivity reactions

B. Type II hypersensitivity reactions

C. Type Ill hypersensitivity reactions

D. Type IV hypersensitivity reactions

B. Type II hypersensitivity reactions

A soluble antigen and soluble antibody reacting to form an insoluble product describes

A. Agglutination reactions

B. Heterophile reactions

C. Labeled reactions

D. Precipitation reactions

D. Precipitation reactions

Which of the following is an example of a treponemal antigen test used for the diagnosis of syphilis?

A. CRP

B. RPR

C. VDRL

D. TP-PA

D. TP-PA

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

After adding sensitized sheep red blood cells in the complement fixation test, it is noted that all of the tubes exhibit hemolysis. 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.

The isotype of an immunoglobulin antibody

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

A patient report states the presence of serum antibodies to OspC. What disease does the patient most likely have?

A. Syphilis

B. Strep throat

C. Lyme disease

D. Rubella

C. Lyme disease

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

Hashimoto disease is an autoimmune disease primarily involving the

A. Kidneys

B. Liver

C. Lungs

D. Thyroid gland

D. Thyroid gland

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

"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

The first serologic marker to appear in patients with acute hepatitis B virus infection is

A. Anti-HB

B. Anti-HBc

C. Anti-HBe

D. HBsAg

D. HBsAg

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)

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

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

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

A. An immunogen from HBV in the vaccine 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 concurrently infected with HBV.

D. HDV requires the host to be concurrently infected with HBV.

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

A patient with suspected human immunodeficiency 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 amplification test on the present sample

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

C. Perform an HIV nucleic acid amplification test on the present sample

The primary target of human immunodeficiency virus

A. B cells

B. Pre-T cells

C. CDA+ T cells

D. CD8+ T cells

C. CDA+ T cells

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 antibody titer be reported?

A. 256

B. 512

C. 640

D. 1280

C. 640

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

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-HAV	Nonreactive
Anti-HBc	Reactive
Anti-HBs	Nonreactive
HBsAg	Reactive
HBeAg	Reactive
Anti-HCV	Nonreactive

Which of the following is the most likely conclusion?

A. Acute HAV infection

B. Acute HBV infection

C. Chronic HB V infection

D. Immunity to HBV due to past infection

C. Chronic HB V infection

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

	IgG Titer	IgM Titer
Cytomegalovirus (CMV)	20	0
Epstein-Barr virus (EBV) VCA	0	80
Mono spot	0	0

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

A male infant had been well until about 5 months of age, at which time he was diagnosed as having otitis media and bronchitis and was treated empirically. Over the next several months he presented with streptococcal pneumonia several times. At 10 months of age, a serum protein electrophoresis 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 exhibited normal mitogen stimulation. What disease does this child most likely suffer from?

A. Combined immunodeficiency

B. DiGeorge syndrome

C. Iatrogenic immunodeficiency

D. X-linked agammaglobulinemia

D. X-linked agammaglobulinemia

A 33-year-old female presents to her primary care provider complaining of increased sweating and palpitations over a 3-month period. She has also lost 15 pounds. Examination 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 peroxidase

D. Pituitary gland hyperactivity

C. Circulating antibodies to thyroid peroxidase

A 38-year-old woman visited her physician because of fatigue, fever, and joint pain (proximal interphalangeal, wrist, and knee joints). She also noticed sensitivity to the sun and reported having a rash following recent exposure. Laboratory results included white blood cell count 5.5 X 10% /L (reference range 4.8-10.8 × 10º /L) and red blood cell count 4.5 X 1012/L (reference range 4.0-5.4 X 10*/L). Urinalysis results were within reference ranges, except for 4+ protein and 1 + red blood cells (RBCs) 0-3 hyaline casts/pf and 0-1 RBC cast/ Ipf on microscopic examination. Which of the following tests would be most helpful in diagnosing this patient's condition?

A. Anti-nuclear antibody

B. a-Fetoprotein

C. Anti-streptolysin O

D. Hepatitis profile

A. Anti-nuclear antibody