Objective: TRAF3 and TRAF5 share a common ancestral gene, and interact as essential components of signaling pathways in immunity. TRAF3 and TRAF5 are overexpressed in the colon of rat/mouse models with colitis. However, the expressions of TRAF3 and TRAF5 in patients with inflammatory bowel disease have not been elucidated. The aim of the present study is to explore the potential roles of TRAF3 and TRAF5 in patients with inflammatory bowel disease.Methods: Plasma levels of TRAF3 and TRAF5 proteins were detected by Enzyme-linked Immunosorbent Assay (ELISA). Colonic expression of TRAF3 and TRAF5 proteins was detected by western blot analysis. Quantitative Real-time PCR (qRT-PCR) was applied for gene expression. Inflamed intestinal mucosa and non-inflamed intestinal mucosa in patients with inflammatory bowel disease and normal mucosa was analyzed from healthy controls.Results: The plasma levels of TRAF3 and TRAF5 were significantly higher both in patients with Crohn's disease and ulcerative colitis than in healthy controls. Only soluble TRAF5 showed a weak correlation with endoscopic disease activity index (Baron score) in patients with ulcerative colitis (spearman's r=0.358, P=0.022). Gene expressions of TRAF3 and TRAF5 in peripheral blood mononuclear cells were significantly higher both in patients with Crohn's disease and ulcerative colitis than in healthy controls (all P<0.0001). Gene and protein expressions of TRAF3 and TRAF5 were significantly higher in inflamed colonic mucosa of patients with Crohn's disease and ulcerative colitis than in non-inflamed colonic mucosa and normal mucosa of healthy controls (all P<0.0001). Furthermore, gene and protein expressions of TRAF3 and TRAF5 were also significantly higher in non-inflamed colonic mucosa of patients with Crohn's disease and ulcerative colitis than in normal mucosa of healthy controls.Conclusions: TRAF3 and TRAF5 are overexpressed in inflammatory bowel disease. Although the endoscopic appearance can be normal, TRAF3 and TRAF5 pre-activation can be detected in non-inflamed colonic segments.

In recent years, interests combining the exploration of tumor necrosis factor receptor-associated factor 4 (TRAF4) and TRAF6 in immune cells and transgenic mice are emerging. Although it has been found that TRAF4 and TRAF6 share the same TRAF binding sites, comprehensive study of TRAF4 and TRAF6 in inflammatory bowel disease (IBD) is still lacking. This paper shows similar and different expression patterns of TRAF4 and TRAF6 in patients with IBD. The results indicate that TRAF4 and TRAF6 are overexpressed in IBD. TRAF4 and TRAF6 play different roles in the pathogenesis of IBD. Moreover, TRAF4 may be an indicator of endoscopic disease activity of UC and TRAF6 preactivation can be detected in noninflamed colonic segments.

Azathioprine (AZA) 2 to 2.5 mg/kg/d is recommended for European patients with Crohn disease (CD), but several Asian studies reported that low dose of AZA was also effective to treat CD. To confirm those observations, we perform this prospective observational study to compare the efficacy and safety of low and standard doses of AZA in the treatment of active CD.This was a prospective, open-labeled observational study. Two hundred twenty-six active CD patients were divided into 2 groups and treated with AZA 1.5 or 2.0 mg/kg/d respectively, combined with steroid therapy. Patients were followed up for 96 weeks. The complete remission (CR) rate, response rate, relapse rate, and adverse effect rate were assessed at weeks 24, 48, and 96 by intention-to-treat (ITT) analysis.Azathioprine 1.5 mg/kg/d showed no significant difference compared with AZA 2 mg/kg/d in CR rate, response rate and relapse rate by ITT analysis at week 24, 48, or 96 (all P > .05). Their adverse effect rates had no significant difference either (P > .05). Up to 21.7% (49/226) of the patients reported adverse events and 69.4% (34/49) of them were myelosuppresion.Azathioprine 1.5 mg/kg/d combined with steroids is as effective as AZA 2.0 mg/kg/d to induce remission of active CD in the first 6 months, and to maintain remission of inactive CD in the first 2 years, without increasing the recurrence of active CD after clinical remission. The most common adverse effect is myelosuppression.