Aberrant alteration of follicular T helper cells in ulcerative colitis patients and its correlations with interleukin-21 and B cell subsets

Abstract

Patients with ulcerative colitis (UC) are at increased risk of developing colitis-associated colon cancer. Accumulating evidence suggests that follicular T helper (TFH) cells play a crucial role in the pathogenic process of autoimmune diseases. However, little is known about the role of TFHcells in the development ofUC. To investigate the role of TFHcells in the development ofUC, the number of TFHcells, the level of interleukin-21 (IL-21), the numbers of B cell subsets, and clinical parameters were detected in peripheral blood from31 UC patients and 29 healthy controls. TFHcells and the level of IL-21 were significantly higher in UC patients than in the healthy controls. A positive correlation between TFHand IL-21 cells was found in UC patients. Moreover, aberrant frequencies of different subsets of B cells were observed inUCpatients, and a positive correlation wasfound betweenCD38+CD19+Bcells and TFHcells and betweenCD86+CD19+B cells and TFHcells. A high number of TFHcells were positively associated with Mayo score, serum C-reaction protein (CRP) and serum IgG in UC patients. Our data indicate that TFHcells and IL-21 are involved in the pathogenesis of UC. Abbreviations: CAC = colon cancer, CD = Crohn's disease, CRP = C-reactive protein, CXCR5 = C-X-C chemokine receptor type 5, DCs = dendritic cells, ELISA = enzyme-linked immunosorbent assay, ESR = erythrocyte sedimentation rate;, GC = germinal centres, HC = healthy control, IBD = inflammatory bowel diseases, ICOS = inducible T-cell costimulator, IL = interleukin, NK cell = natural killer cell, PBMCs = peripheral blood mononuclear cells, RA = rheumatoid arthritis, RORγt = RAR-related orphan receptor gamma 2, SLE = systemic lupus erythaematosus, SS = Sjögren's syndrome, TFH= follicular T helper cells, TH= T helper cells, UC = ulcerative colitis.