CD4+CD25+ regulatory T cells in peripheral blood of patients with ankylosing spondylitis / 中华风湿病学杂志

ABSTRACT

Objective To characterize and quantify the CD4 +CD25 + regulatory T (Treg) cell population in peripheral blood of patients with ankylosing spondylitis (AS) and to determine the influence of treatment with tumor necrosis factor (TNF)-a inhibitors on them.Methods Peripheral blood mononuclear cells (PBMC) were isolated from 25 patients with active AS,in which 10 patients were treated with 12 weeks of etanercept,and 21 healthy subjects.CD4+CD25high T cells were analyzed using flow cytometry,and mRNA expression of FOXP3 was determined by real-time polymerase chain reaction (PCR).Proliferation of T cells to PHA was measured by WST-1 assay using depleted CD25+ cells by immunomagnetic sorting.Results There was no significant difference in the percentage of CD4+CD25high cells in peripheral blood between patients with active AS and controls (P＞0.05).However,PBMC from patients with active AS expressed reduced levels of FOXP3 mRNA (P＜0.01) which were inversely correlated with C-reactive protein (CRP)(P＜0.01).CD4+CD25+ cells in peripheral blood of both active AS patients and controls exhibited suppressive capacity on the proliferation of effector T cells in vitro (both P＜0.01).Treatment with etanereept increased significantly CD4+CD25high cells and FOXP3 mRNA expression (both P＜0.01),with negative correlations between these increases and decrease in CRP levels (P＜0.05 and P＜0.01,respectively).Conclusion In AS patients,peripheral FOXP3-expressing CD4 +CD25 + Treg cells are abnormal,and are up-regulated by etanercept treatment.This suggests a possible pathogenesis of AS and a potential mechanism for clinical efficacy of TNF-α inhibitors.