An increase in serum tumor necrosis factor-α during anti-tumor necrosis factor-α therapy for Crohn's disease–a paradox or a predictive index?

Abstract Background Soluble tumor necrosis factor-α (sTNF-α) have been reported to increase in the course of anti-TNF-α therapy for rheumatoid and skin diseases. Aims To assess changes in sTNF-α and clinical efficacy of anti-TNF-α agents in Crohn's disease (CD). Methods Sixty-four patients on infliximab or adalimumab were analyzed. Clinical outcomes were assessed by using CD Activity Index after the induction therapy and at week 52. sTNF-α was measured before and after the induction therapy with high-sensitivity immunoassay. Results In the majority of patients, sTNF-α increased significantly. Those with the greatest increase were more likely to experience long-term response, were more often treated with infliximab, had less frequently isolated small bowel CD, and tended to have sTNF-α levels at baseline that correlated with C-reactive protein. Conclusions Neutralization of sTNF-α does not seem to be critical for the efficacy of anti-TNF-α therapy in CD. Paradoxically–an increase in sTNF-α may reflect an ongoing process that is beneficial for the clinical outcome.