IDENTIFICATION OF ACTIVATED T-CELLS IN SARCOIDOSIS

Abstract

When peripheral blood lymphocytes are stimulated by mitogens or allogeneic cells, they acquire the capacity to form stable rosettes at 37.degree. C with sheep red blood cells, thereby identifying a population of activated T [thymus-derived] cells. In 7 consecutive patients with acute sarcoidosis, there was a significant (P < 0.005) increase in the proportion and the total number of peripheral blood lymphocytes forming stable rosettes at 37.degree. C compared to age-matched normal control subjects (12.6 .+-. 3.0% vs. 2.0 .+-. 0.3%, respectively). This occurred despite a significant decrease in the total number of lymphocytes (P < 0.01) and T cells (P < 0.001) in the peripheral blood in these same patients. Light microscopic and EM examination of sarcoid lymphocytes confirmed that cells forming stable rosettes at 37.degree. C were activated or atypical. In acute sarcoidosis activated T cells are increased; the total number of T cells is decreased in peripheral blood. This finding posed certain technical problems in identifying B [bone marrow-derived] cells by surface immunoglobulin and complement receptors. Measures to overcome these difficulties are discussed. As determined by 2 independent tests of B cells (i.e., complement receptor and surface immunoglobulin), the number of circulating B cells was decreased.