Sarcoidosis: correlation of delayed hypersensitivity, MLC reactivity and lymphocytotoxicity with disease activity.

Delayed skin reactivity to a battery of antigens was assessed for a series of sarcoidosis patients and closely matched controls. It was compared with the proliferative and cytotoxic capacity of corresponding blood lymphocyte preparations after challenge in mixed lymphocyte culture with an allogeneic lymphoma cell line. Skin anergy to all antigens tested was found only within the patient group having definitely active disease. These patients also showed depression of lymphocyte proliferative response in the test system as compared to matched controls and to patients with apparently inactive disease. Both of these differences were statistically significant. Skin reactivity to tuberculin was significantly depressed for the whole sarcoidosis group (both active and inactive) as compared to the control group and significant impairment of capacity to develop cytotoxicity was also found in comparison of these same groups. The results obtained confirm the association of impaired delayed skin hypersensitivity in sarcoidosis with diminished lymphocyte reactivity , especially when the disease is active. The reduced cytotoxic capacity of sarcoid lymphocytes may reflect a comparable impairment and partly explain the depressed skin tests and also contribute to the protracted nature of the disease because of failure to eradicate the postulated `sarcoid agent'.