Abstract

The presence within the epithelioid granulomas of sarcoidosis of lymphocytes of the "helper" (T4 positive) phenotype suggests that, as in granulomatous diseases of known aetiology, active cell mediated immunity plays a part in the disease. It has, however, been noted that T8 positive lymphocytes are also found on occasion in the granulomas. The presence of cells bearing markers associated with suppressor activity in various lesions of sarcoidosis has been investigated with a range of monoclonal antibodies. T4 positive cells were present in all granulomas; T8 positive lymphocytes were present within the epithelioid cell areas in proportions that varied from 5 to 55/100 of T4 cells. Other lymphocyte markers associated with suppression (Leu8 and SN130) were very rare on lymphocytes within granulomas but common on both T4 positive and T8 positive lymphocytes in the perigranulomatous mantle, which suggests that expression of these markers was down regulated in the granuloma or that cells bearing them are unable to migrate into the granuloma. Nevertheless, suppressor cell mechanisms could mediate the spontaneous resolution of most cases of sarcoidosis, and the presence or absence of cells bearing suppression associated phenotypes in the granuloma or its mantle may have prognostic importance.