A search for thymie (T) lymphocyte inhibitory factors in sarcoid sera

Sarcoid patients frequently show depression of skin delayed hypersensitivity reactions suggesting depression of thymic (T) lymphocyte function. In vitro demonstration of such depression, however, to date, is inconclusive. We have used the macrophage migration inhibition test with Kveim "antigen" (KMIF), and spontaneous sheep red cell rosetting (SRC) techniques as indicator systems. We found that a positive KMIF test obtained in 7 of 16 subjects (13 sarcoid and 3 non sarcoid) in the presence of foetal bovine sera (FBS) became negative in the presence of sarcoid patients sera. Using lymphocytes from a single normal healthy subject the SRC tests were performed in the presence of sarcoid, normal healthy sera and FBS. With sarcoid sera 38% of lymphocytes showed rosetting as compared with normal human sera, 54%, and with FBS, 57%. Where lymphocytes were pre-incubated for one hour in the various sera the percentage of rosetting cells were even further reduced, sarcoid sera 23%, as compared to normal human sera, (49%), and FBS, (54%). Thus, using two tests of lymphocyte function our preliminary results suggest the presence of T cell inhibitory factors in sarcoid sera.