Increased serum soluble OX40 in patients with systemic sclerosis

Objective. To determine levels of serum soluble OX40 (also termed CD134, a member of the tumor necrosis factor receptor superfamily) and their clinical associations in patients with systemic sclerosis (SSc). Methods. Serum soluble OX40 levels were examined by ELISA in 53 patients with SSc, 15 patients with systemic lupus erythematosus (SLE), and 32 healthy individuals. Results. OX40 levels were significantly elevated in SSc patients (125.7 ± 5.7 pg/ml) compared to patients with SLE (80.7 ± 1.7 pg/ml; p < 0.005) and controls (88.2 ± 3.0 pg/ml; p < 0.0001). Elevated OX40 levels were found to be associated with disease duration of less than 2 years (p < 0.05). Conclusion. Our results suggest that serum soluble OX40 levels correlate with the early-onset of SSc disease.