Immunohistological evidence of lymphokine production and lymphocyte activation antigens in tuberculin reactions.

Evidence of lymphokine elaboration and lymphocyte activation was sought in tuberculin skin test reactions at 24 and 48, or 48 and 96 h in patients with active, culture-proven, pulmonary tuberculosis. Through the use of frozen sections, immunoperoxidase techniques and monoclonal antibodies, anti-interleukin 2 positive cells were found to constitute 0.4% to 0.6% of the dermal infiltrate, and keratinocyte Ia expression at 96 h was consistent with a marker for interferon-gamma production. Cells bearing the interleukin 2 receptor more than doubled in prevalence from 24 to 48 or 96 h but cells staining with Ta1, an antibody identifying activated lymphocytes, were 10% of the cells of the infiltrate at all three times. One-half of the cells of the infiltrate were OKM1-positive, presumably macrophages, perhaps reflecting the presence of active tuberculosis.