MLPAO MLPAO Immunology and Serology 3

Question 1

Rheumatoid factor (RF) is typically an autoantibody of which immunoglobulin class directed against:

Accepted Answer

IgM directed against patient's own IgG

Answer

IgA directed against collagen

Answer

IgG directed against nuclear antigens

Answer

IgE directed against IgM

Question 2

In flow cytometry, CD4:CD8 ratio is used clinically to monitor patients with HIV. A significantly decreased ratio (below 1.0) indicates:

Accepted Answer

Progressive immunodeficiency due to CD4+ T cell depletion

Answer

Polyclonal B cell activation

Answer

A normal healthy immune response

Answer

Increased natural killer cell activity

Question 3

The Weil-Felix test uses Proteus vulgaris antigens to detect antibodies in patients suspected of having:

Accepted Answer

Rickettsial infections

Answer

Brucellosis

Answer

Lyme disease

Answer

Syphilis

Question 4

Which principle underlies the fluorescent treponemal antibody absorption (FTA-ABS) test for syphilis?

Accepted Answer

Indirect immunofluorescence after absorption of non-specific antibodies

Answer

Complement fixation using treponemal antigen

Answer

Latex agglutination with cardiolipin antigen

Answer

Direct ELISA with recombinant treponemal peptides

Question 5

In immunofixation electrophoresis (IFE) for serum protein analysis, a monoclonal band (M-protein) in the gamma region most commonly suggests:

Accepted Answer

A plasma cell dyscrasia such as multiple myeloma

Answer

Polyclonal hypergammaglobulinemia from chronic infection

Answer

Normal immunoglobulin production

Answer

IgA deficiency

Question 6

Which quality control measure is most important when performing agglutination serological tests to ensure reagent validity?

Accepted Answer

Running known positive and negative controls with each test batch

Answer

Checking the expiry date only

Answer

Storing all reagents at room temperature

Answer

Performing the test in duplicate only for positive results

Question 7

Serum protein electrophoresis (SPEP) separates proteins primarily based on:

Accepted Answer

Electrical charge and molecular size in an alkaline buffer

Answer

Molecular weight only

Answer

Antigen-antibody affinity

Answer

Complement activation capacity