42 yr old - kiranraja

[ArchivalUser]

A 42-year-old Nigerian in the United States visiting his brother comes to the clinic with complaints of several months of weight loss, night sweats, sputum production, and occasional spitting up blood. His physician places a tuberculin skin test and the results are positive. This positive tuberculin test indicates which of the following.

A. A cell-mediated immune response has occurred
B. A humoral immune response to TB is positive
C. The B and T cell systems are functional
D. The B cell system is functional
E. The phagocytic neutrophilic system is functional

[ArchivalUser]

AAAA

[ArchivalUser]

aa

[ArchivalUser]

A..

[ArchivalUser]

aa

[ArchivalUser]

i have a doubt... when u inject tuberculin into the skin, is it NOT taken up my the macrophages of the skin?

[ArchivalUser]

Answer is : A

The tuberculin skin test is a delayed type hypersensitivity test. This type IV
hypersensitivity is a cell-mediated immune response involving CD4 T helper 1 (TH1) lymphocytes.

Elimination of tuberculosis, like all intracellular bacterial infections, is not dependent on a humoral (antibody) response (choice B).

This patient could have antibody to tuberculosis, but recovery is entirely dependent on cell-mediated immunity.