Suppressor cell loss and dysfunction in mixed connective tissue disease.

Of 11 patients with untreated mixed connective tissue disease (MCTD) who were studied, all had decreased circulating T gamma cells, and all but one had decreased suppressor cell function of T cells on B cells, determined by a reverse hemolytic plaque-cell assay. Results in 21 normal subjects were significantly, different. Incubation of mononuclear cells from MCTD patients in purified anti-ribonucleoprotein (anti-RNP) IgG resulted in further decrease in their suppressor function. Decrease of T gamma cells and their suppressor function may be due to in vivo penetration of anti-RNP antibody into T gamma cells, causing their deletion.