Lymphocyte subpopulations in sarcoidosis: correlation with disease aetivity and duration.

We studied lymphocytes from the peripheral blood of 29 sarcoid patients to relate T- and B-cell populations with disease activity and duration. In patients with acute (less than 1 year) and chronic (greater than or equal to 9 years) active disease, the absolute lymphocyte count was reduced; the absolute number of T cells was reduced; and the proliferative response of lymphocytes to phytohemagglutinin was depressed compared with control subjects. Ten of 21 patients with active disease had 5% to 32% atypical lymphocytes. The proportion of cells bearing surface immunoglobulin (Ig) was increased in patients with active disease, but the absolute number of cells bearing surface Ig did not differ significantly from controls. However, studies using overnight in-vitro culture indicated that a large fraction of these cells bound exogenous Ig. The number of cells indentified by complement receptors was significantly reduced in patients with active disease. In contrast, patients who had complete reasolution of their disease showed no significant differences from controls in either T- or B-cell populations or in the proliferative response of their lymphocytes to phytohemagglutinin.