Role of CD4 + CD25 + regulatory T cells in the patients with ulcerative colitis

Abstract

Objective To investigate the levels of CD4 + CD25 + regulatory T cells and the Foxp3 in the peripheral blood of patients with ulcerative colitis ( UC), and analyze its role in the pathogenesis of UC. Methods From February 2007 to December 2008, 40 UC patients (23 active and 17 remissive), 33 irritable bowel syndrome (IBS) patients, and 32 normal controls entered our study. CD4 + CD25 + T cells were detected with flow cytometric assay. The expression of Foxp3 mRNA in peripheral blood mononuclear cell (PBMC) was detected by RTPCR. Interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) in the serum from the peripheral blood of UC patients, IBS patients, and normal controls were determined with ELISA. Results There were no significant differences of the peripheral CD4 +T cell numbers among the active, remissive UC and IBS patients, and normal control groups (P=0. 126). The positive rate of CD4+ CD25+ T cells in patients with active and remissive UC were significantly lower than those in IBS patients and normal controls ( both P ＜ 0. 01 ) it was more lower in the active UC patients than the remissive UC patients ( P ＜ 0. 001 ). However, the positive rate of CD4 + CD25 + T cells showed no significant difference between IBS patients and normal control groups ( P = 0. 343 ). The percentage of CD4 + CD25 + T cells was negatively correlated with UC disease activity index ( r = - 0. 660, P ＜ 0. 001 ) and with erythrocyte sedimentation rate (r = -0. 572, P =0. 001 ). The expressions of Foxp3 mRNA in PBMC from active and remissive UC patients were significantly lower than those in both IBS patients and normal controls ( both P ＜0. 001 ). There was no significant difference of the plasma levels of IL-10 or TGF-β among the active/remissive UC patients, IBS patients, and normal controls ( all P ＞ 0. 05 ). Conclusions CD4+ CD25 + regulatory T cells remarkably decline in the active UC and show certain increase in remissive UC, indicating that these cells may be involved in the pathogenesis of UC. The decreased expression of Foxp3 mRNA may be an important factor of the aberrant developmental disorder of CD4 + CD25 + regulatory T cells. Key words: Ulcerative colitis; CD4 + CD25 + T cell; Foxp3