Background: It has been documented that treatment with infliximab (IFX) induces remission in 1/3 of patients with moderate to severe ulcerative colitis (UC). Predictors of response could improve selection of patients with a higher probability of favorable outcome.

Objective: To determine predictor factors for the clinical outcome of IFX induction therapy in UC.

Methods: UC patients with moderate to severe disease who received 5mg/kg IFX at weeks 0, 2 and 6weeks were included. Ulcerative colitis disease activity index (UCDAI) score including endoscopic sub-scores were assessed before and after treatment. Several predictors, including TNF-alpha mRNA expression, were tested in a regression model.

Results: Fifty-nine patients completed the study. Age, gender, steroid therapy, immunosuppressive, pancolitis, endoscopic sub-score, disease duration, C-reactive protein, interleukin-(IL)-4, IL-10 or interferon-gamma (IFN-gamma) did not predict mucosal or clinical remission. There was an inverse and independent association between pre-treatment TNF-alpha expression levels and clinical and endoscopic remission of IFX treatment (logistic regression, p=0.01 and p=0.003, odds ratio 2.5 and 4.8, respectively).

Conclusions: The clinical outcome of an induction therapy with IFX in UC is inversely associated with the pre-treatment gene expression levels of TNF-alpha in colorectal mucosa.