Question 1

Deposition of AL amyloid in the kidneys of patients with multiple myeloma usually results in

Accepted Answer

Deposits of AL amyloid are typically found in the glomeruli, causing proteinuria. Proteinuria is often severe, leading to a full blown nephrotic syndrome.

Question 2

A 40-year-old man presents with hemoptysis and renal failure. A kidney biopsy specimen revealed linear deposits of IgG in glomerular basement membranes and crescents between the glomerular capillary loops and the Bowman capsule. The antibodies causing these pathologic changes react with

Accepted Answer

This man has Goodpasture syndrome, in which the body produces autoantibodies to the globular part of type IV collagen in the glomerular basement membranes and the lungs.

Question 3

The most common fungal pathogen infecting the mouth and the esophagus of patients with AIDS is

Accepted Answer

In general, the most common fungal pathogens in patients with AIDS is Candida albicans. Most often, it infects the mouth and the esophagus, but it can be found in many internal organs such as the vagina.

Question 4

A 10-year-old girl presented with lilac or heliotrope discoloration of the upper eyelids, muscle weakness, and dusky red patches over the knuckles, elbows, and knees. Which antibody was most likely found in this patient's blood?

Accepted Answer

This girl most likely has dermatomyositis. The antibody most commonly found in inflammatory myopathies is directed against the histidyl-t-RNA.

Question 5

Mutation of the gene encoding the enzyme that is essential for the maturation of pre-B cells to mature B lymphocytes is the cause of

Accepted Answer

X-linked agammaglobulinemia (Bruton agammaglobulinemia) is caused by the mutation of Bruton tyrosine kinase (Btk), an enzyme essential for the maturation of pre-B cells into B lymphocytes. Because the defective B lymphocytes cannot produce immunoglobulins, there is agammaglobulinemia and reduced resistance to infections.

Question 6

Which antibody can most effectively activate complement by the alternate pathway, even without prior forming an antigen-antibody complex?

Accepted Answer

IgA can activate complement by the alternate pathway.

Question 7

Antigen-antibody reaction in polyarteritis nodosa is characterized by which form of necrosis of the arterial wall?

Accepted Answer

Antigen-antibody complexes cause inflammation of the vessel wall, accompanied by the insudation of plasma proteins into the site of injury. The necrosis is classified as fibrinoid, because it contains large amounts of fibrin formed from fibrinogen in the plasma insudated into the damaged vessel wall.

Question 8

In addition to T-helper lymphocytes, which other cells serve as a major reservoir for the human immunodeficiency virus in lymph nodes?

Accepted Answer

The human immunodeficiency virus lives and replicates in CD4+ T-helper lymphocytes and follicular dendritic cells in the germinal centers of lymph nodes.

Question 9

The formation of vesicles in contact dermatitis caused by poison ivy is primarily mediated by

Accepted Answer

TH1 helper lymphocytes accumulate first at the site of exposure to the foreign antigen in the skin; they also are the most important mediators of epidermal cell injury that leads to formation of vesicles and bullae. CD8 cytotoxic cells also take part in later stages of the reaction, but to a lesser degree.

Question 10

Which molecule on the surface of lymphocytes serves as the receptor for the human immunodeficiency virus (HIV)?

Accepted Answer

CD4, the cell surface marker of T-helper lymphocytes, serves as a high affinity receptor for the human immunodeficiency virus.

Question 11

Which of the following is the most abundant bronchospasm-inducing arachidonic acid derivative generated by cyclooxygenase in the mast cells?

Accepted Answer

Prostaglandin D₂ is the most abundant arachidonic acid derivative produced through the cyclooxygenase pathway. It causes bronchospasm and increased mucus production.

Question 12

Generic antinuclear antibodies are found in more than 95% of patients with systemic lupus erythematosus. Which pattern of staining seen on tissue culture cells in the indirect antibody immunofluorescence microscopy test signifies the presence of these antibodies?

Accepted Answer

Generic antinuclear antibodies (ANA) reacting with chromatin, histones, and occasionally double-stranded DNA give a diffuse nuclear staining pattern. Rim (or peripheral) staining is due to antibodies to double-stranded DNA. A speckled pattern is typical of antibodies to non-DNA nuclear components, including the Sm-antigen, which is the most specific marker of systemic lupus erythematosus. A nucleolar pattern reflects the presence of antibodies to nucleolar RNA. Cytoplasmic staining is nonspecific and unrelated to antinuclear antibodies.

Question 13

Amyloid deposited in the tissue of patients who are on dialysis for chronic renal failure is most often biochemically related to which precursor protein?

Accepted Answer

ß₂-microglobulin is a component of the major histocompatibility complex on the cell surface and is also normally present in deposits in the tissues of patients on long-term hemodialysis, forming amyloid fibrils.

Question 14

Which of the following blood studies is the best evidence of microvascular endothelial cell injury that typically occurs in systemic sclerosis (scleroderma)?

Accepted Answer

Von Willebrand factor is produced and stored in endothelial cells. An endothelial cell injury leads to elevated levels of this factor in blood.

Question 15

Which of the following is the predominant and most common cardiovascular manifestation of systemic lupus erythematosus?

Accepted Answer

Pericarditis is the most common cardiovascular manifestation of systemic lupus erythematosus.

Question 16

The most common and the most serious form of renal disease encountered in systemic lupus erythematosus (SLE) is classified as x. Most of the lesions found in SLE are mediated by the deposition of immune complexes (type III hypersensitivity reaction). Which pathologic reaction is due to type II hypersensitivity (cytotoxic) reaction?

Accepted Answer

The most common and clinically the most serious form of lupus nephritis is class IV, diffuse proliferative glomerulonephritis.

Question 17

Antibodies to centromere are found in patients who have

Accepted Answer

Almost all patients who have anti-centromere antibodies have a form of scleroderma called CREST. Symptoms of CREST syndrome, a limited form of scleroderma, are calcinosis, Raynaud syndrome, esophageal dysmotility, sclerodactyly, and telangiectasis. In contrast to CREST syndrome, systemic sclerosis is characterized by the appearance of antibodies to DNA topoisomerase (anti-Scl 70).

Question 18

Autoantibodies to IgA are found in approximately 40% of patients who have

Accepted Answer

Although they lack IgA in their blood and secretion, patients with congenital isolated IgA often have antibodies to IgA. Transfusion of blood to these patients may result in severe anaphylactic reaction due to the reaction of the patient's autoantibodies and the IgA in the transfused blood.

Question 19

Which antibodies are considered to be markers of Sjögren syndrome?

Accepted Answer

Anti-ribonucleoprotein antibodies (RNP) are found in about 90% patients with Sjögren syndrome and are found in less than 5% of patients with other autoimmune diseases. Hence, these anti-RNP antibodies, called SS-A and SS-B, are very good markers for this disease.

Question 20

A 23-year-old woman was given an intradermal injection of purified protein derivative of tubercle bacilli (PPD) as part of the yearly testing for tuberculosis. A positive reaction was elicited. Which cells secrete the cytokines needed for the formation of granulomas at the site of injection?

Accepted Answer

Granuloma formation depends on cytokines produced by T_H1 cells derived from CD4+ lymphocytes.

Quiz 4: Diseases of the Immune System