[Phenotypic analysis of Th cells in colon and peripheral blood in patients with irritable bowel syndrome].
OBJECTIVE; To analyze the change of Th1/Th2/Th17 in colonic mucosa and peripheral blood in diarrhea-predominant IBS (D-IBS) to uncover the underlying mechanism for the activation of mucosal immune system.


METHODS
Colonic biopsy specimens and peripheral blood were obtained from patients with D-IBS (n = 27) and controls (n = 16). Two different groups were classified on the basis of histological assessment of biopsy specimens from D-IBS patients. One group (14 of 27) had normal conventional histology (IBS), while another group (13 of 27) had nonspecific microscopic inflammation (IBS-A). Flow cytometric detection of intracellular IFN-gamma/IL-4/IL-17 cytokine production was employed to investigate Th1, Th2 and Th17 cells in colonic lamina propria and peripheral blood. Western blot was used to determine the expressions of IL-12, IL-4 and IL-17 in colonic mucosa. The levels of IL-12, IL-4 and IL-17 in peripheral blood were detected by ELISA.


RESULTS
In colonic mucosa, the proportion of Th17 increased in IBS-A group as compared with controls [3.60 (4.05) vs 1.25 (3.70), P = 0.045], but not in IBS group. No difference could be observed in the frequencies of Th1 and Th2 in colonic mucosa and peripheral blood. The levels of IL-12, IL4 and IL-17 in IBS and IBS-A showed no difference in either colonic mucosa or peripheral blood.


CONCLUSIONS
Subgroup of D-IBS showed abnormal conventional histology, implicating the activation of mucosal immune system in pathogenesis. The shift of Th1/Th2/Th17 balance in colonic mucosa showed the enhanced Th17 activity.
Fu
Yu
Y
Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan 430022, China.
Tong
Jing-Jing
JJ
Pan
Qi
Q
Wang
Wen-Feng
WF
Zou
Kai-Fang
KF
Qian
Wei
W
Hou
Xiao-Hua
XH
D000293:Adolescent; D000328:Adult; D003106:Colon / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology*; D043183:Irritable Bowel Syndrome / Q000097:blood* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D016176:T-Lymphocyte Subsets / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*; D055815:Young Adult