RESUMO
Objective To investigate the effect of infection on the expression of substance P(SP) and Th1 cytokine on colonic mucosa in patients with irritable bowel syndrome(IBS).Methods Mucosa biopsy samples were obtained in descending colon and rectum from 77 patients(20 post-infective-IBS cases)and 30 controls by colonoscopy.The expressions of SP,interleukin(IL)-2,interferon(IFN)-?were determined by immunohistochemical staining.Results Compared with controls,expressions of SP,IL-2 and IFN-?were significantly increased in IBS patients with diarrhea-predominant(P＜0.05),and expression of SP in post-infective-IBS patients with cytokines positive(IL-2 and IFN-?)were also signifi- cantly increased(P＜0.05).There were no significant differences between non post-infective-IBS and controls.Conclusions Expression of SP was significantly increased in post-infective-IBS.SP upregulated the expression of Thl cytokines(IL-2 and IFN-?).Gastrointestinal infection may involve in the patho- genesis of IBS through neuroimmune mechanism.