To assess the relationship between serum concentrations of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and osteoprotegerin (OPG) and the therapeutic response to disease-modifying antirheumatic drugs (DMARD) in patients with early rheumatoid arthritis (RA).
Circulating levels of TRAIL and its soluble receptor OPG were measured by ELISA in paired serum samples obtained from 66 patients with early RA at their first visit (baseline) and after 1 year of therapy. Levels of TRAIL and OPG were analyzed in relation to the clinical response, defined by the 28-joint count Disease Activity Score (DAS28).
Both serum TRAIL and OPG increased after DMARD therapy. Baseline levels of TRAIL, but not OPG, were significantly higher (p < 0.05) in the patients that achieved a clinical response by DAS28 after 1 year of therapy, versus patients without clinical response to DMARD. Baseline serum levels of TRAIL were higher (p < 0.01) in rheumatoid factor-negative patients.
Our data suggest that the basal level of circulating TRAIL is an important determinant in the therapeutic response to DMARD in patients with early RA.