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.