When a tuberculin skin test is positive, the hard center and erythema surrounding the induration are a result of:
A)histamine.
B)T lymphocytes and macrophages.
C)immune complexes.
D)products of complement.

Question

Quizplus · Accepted Answer

The reaction site is infiltrated with T lymphocytes and macrophages, resulting in a clear hard center (induration) and a reddish surrounding area (erythema).

When a Tuberculin Skin Test Is Positive, the Hard Center