Interleukin (IL)-4 and IL-17 synergistically stimulate IL-6 secretion in human colonic myofibroblasts.

There is increasing evidence that interleukin (IL)-4 can aid in Th1-type inflammatory responses in chronic colitis models. In this study, we evaluated the effects of IL-4 and/or IL-17 on IL-6 secretion in human colonic myofibroblasts. IL-6 secretion was determined by ELISA and Northern blotting. IL-6 secretion was rapidly induced by either IL-4 or IL-17. IL-17 induced IL-6 mRNA expression within 1 h after stimulation, and reached a maximum at 3 h. IL-6 mRNA induction by IL-4 occurred more rapidly. A maximum induction of IL-6 mRNA by IL-4 was observed at 1 h after stimulation, and this was rapidly decreased. The combination of IL-4 plus IL-17 greatly enhanced IL-6 secretion and mRNA expression. In conclusion, IL-4, in particular IL-4 plus IL-17, induced IL-6 secretion in human colonic myofibroblasts. Th2 immune responses might play an important role in the pathogenesis of gut inflammation.