Serum levels of interleukin 6 (IL-6), oncostatin M, soluble IL-6 receptor, and soluble gp130 in patients with systemic sclerosis.

Abstract

To determine whether serum interleukin 6 (IL-6), oncostatin M (OSM), soluble IL-6 receptor (sIL-6R), and soluble gp130 (sgp130) levels in patients with systemic sclerosis (SSc) are elevated and whether they are correlated with the clinical or serological features of the disease. Serum samples from patients with SSc (n = 55) and control subjects (n = 20) were investigated by ELISA. Patients were divided into 4 groups: 12 with limited cutaneous SSc (lSSc) < or = 3 years' duration (early lSSc), 22 with lSSc > 3 years' duration (late lSSc), 9 with diffuse cutaneous SSc (dSSc) < or = 3 years' duration (early dSSc), and 12 with dSSc > 3 years' duration (late dSSc). Serum IL-6 levels were significantly elevated in patients with early dSSc compared with controls. In addition, serum IL-6 was detected more frequently in patients with pulmonary fibrosis, and these values were inversely correlated with the percentage of vital capacity of individual patients. Furthermore, serum IL-6 levels were correlated with erythrocyte sedimentation rates, C-reactive protein, and IgG and IgA levels in patients. Serum sIL-6R levels were significantly higher in patients with lSSc versus controls. Serum OSM and sgp130 levels were not significantly elevated in patients with SSc compared with controls. We suggest that IL-6 and sIL-6R may contribute to the disease process in SSc. In particular, IL-6 may be related to the early phase of the disease and the development of pulmonary fibrosis in SSc.