Increased Serum Soluble CD40 Levels in Patients with Systemic Sclerosis

OBJECTIVE: To determine serum levels of soluble CD40 (sCD40) and clinical association in patients with systemic sclerosis (SSc). METHODS: Serum sCD40 levels were examined by ELISA in 49 patients with SSc, 15 patients with systemic lupus erythematosus, and 26 healthy individuals. sCD40 levels in plasma samples, which were obtained at the same time, were also determined. SSc patients were grouped into 22 patients with limited cutaneous SSc (lcSSc) and 27 patients with diffuse cutaneous SSc (dcSSc). RESULTS: There was no significant difference between sCD40 levels of sera and those of plasma. Serum sCD40 levels were significantly elevated in patients with SSc compared to patients with systemic lupus erythematosus and controls (p < 0.001). Serum sCD40 levels were higher in patients with lcSSc than in those with dcSSc (p <0.001). There was no correlation between sCD40 and sCD40 ligand levels in patients with SSc. CONCLUSION: Elevated serum sCD40 levels were associated with lcSSc. These results suggest that the blockade of CD40/CD40 ligand interaction could be a potential therapeutic strategy in SSc.