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

Soluble tumour necrosis factor-α (sTNF-α) has been reported to increase in the course of anti-TNF-α therapy for rheumatoid and skin diseases.To assess changes in sTNF-α and clinical efficacy of anti-TNF-α agents in Crohn's disease (CD).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.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.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.