Study Objective: To assess whether interleukin-2 has a role in the pathogenesis of scleroderma.
Design: Observe serum effect on the in-vitro growth of an interleukin-2-dependent cytotoxic T-cell line and determine serum level by an enzyme-linked immunosorbent assay.
Setting: Outpatient rheumatology clinic of a university medical center.
Patients: Sera were collected from 47 patients with scleroderma, 20 patients with rheumatoid arthritis, and 14 matched control subjects.
Measurements and Main Results: A significant mitogenic effect was observed in sera from patients with scleroderma of recent onset; a lower proliferative response was seen in rheumatoid sera. Matched control sera had no mitogenic activity. Sera from patients with scleroderma of recent onset supported the in-vitro growth of an interleukin-2-dependent cytotoxic T-cell line. Matched control sera had no similar mitogenic activity. Interleukin-2 was found in sera from 41 of 47 patients with scleroderma (204 ± 356 U/mL, mean + SD), in 9 of 20 patients with rheumatoid arthritis (2.04 + 5.16), and in none of 14 matched control subjects. There was a positive correlation between serum level and the skin progression index (skin score/disease duration).
Conclusions: The presence of interleukin-2 in scleroderma sera strongly supports a role for T-cell activation in scleroderma. The association between serum levels and disease progression indicates that this T-cell process may participate in the progression of the disease.