Soluble immunologic products in scleroderma sera.

To investigate the role of immune mechanisms in scleroderma (systemic sclerosis, SSc), we measured the levels of selected cytokines and soluble immune markers in patient sera. Forty-two patients and 14 matched healthy controls are the subject of this report. In the SSc group, tumor necrosis factor (TNF) was found in 8/42 (29 +/- 539 pg/ml, mean level +/- SD) and lymphotoxin in 36/42 (1:409-1:200, serum dilution). Interleukin beta (IL-1 beta) was observed in 23/42 (44 +/- 29, U/ml). IL-2 was identified in 36/42 patients with a mean level of 286 +/- 406 U/ml, soluble interleukin-2 receptor in 42/42 (1055 +/- 393, U/ml), soluble CD4 antigen in 27/42 (1:10-1:320, serum dilution), and CD8 in 42/42 (470 +/- 134, U/ml). TNF, lymphotoxin, IL-1 beta, Il-2, and CD4 were not detected in the control group. IL-2 receptor levels in control subjects were 520 +/- 171 U/ml, significantly lower than those of scleroderma (P less than 0.001), and CD8 levels (582 +/- 140) were significantly higher than in scleroderma (P less than 0.05). The data suggest an ongoing activation of immune cells, particularly the CD4+ subset in SSc and indicate a potential role for the released mediator TNF, IL-1 beta, and lymphotoxin in the disease process.