In vitro study of macrophages from patients with sarcoidosis.

Cultures of leukocytes from patients with sarcoidosis were stimulated with Kveim antigen or PPD-S and the macrophage reactions were compared with those obtained under similar conditions with leukocyte cultures from healthy tuberculin reactors. The non-stimulated control cultures of Kveim-positive sarcoid patients showed signs of macrophage activation, namely an increase in cytoplasmic pyroninophilia in small and enlarged macrophages, together with a higher than normal rate of lymphoblast transformation. In the presence of Kveim antigen this activation was more marked, even in cases where the blast response to the antigen was of low magnitude. Stimulation with tuberculoproteins produced a slight activation of macrophages only in cultures from Kveim reactors who had also shown positive tuberculin reactions.These observations suggest that the study of lymphocyte transformation together with that of macrophage activation will improve the immunocytological assessment of sarcoidosis.