Lymphocyte subpopulations in sarcoidosis.

Highly purified blood lymphocytes from sarcoidosis patients were characterized by rosette technique for the presence of receptors for complement and by indirect immunofluorescence for the presence of membrane-bound immunoglobulin (B cells). T cells were estimated by spontaneous rosette formation with sheep red blood cells. The proportion of B cells was significantly higher and the proportion of T cells significantly lower than in the control group. Marked lymphocytopenia was found in the patient group. As a consequence the total number of circulating B cells was normal whereas the total number of circulating T cells was significantly depressed. Large atypical mononuclear cells were found in most patients. One-third of these cells had receptors for human complement.