强直性脊柱炎患者外周血CD4+调节性T细胞的变化及意义

目的 探讨强直性脊柱炎(ankylosing spondylitis,AS)患者外周血中CD4+调节性T细胞(regulatory T cells,Treg)的表达、功能及意义.方法 采用流式细胞术检测78例AS患者和50例健康志愿者外周血中CD4+CD25+CD127lo/- Treg、细胞毒性T细胞(cytotoxic T lymphocytes,CTL)和NK细胞,采用ELISA法检测血清中β型转化生长因子(transforming growth factor-β,TGF-β)和肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)的表达水平.从患者外周血单个核细胞中磁珠分选出CD4+CD25+ Treg细胞,混合淋巴细胞培养(mixed lymphocyte culture, MLC)分析其免疫抑制功能.结果 AS活动期患者外周血中CD4+CD25+CD127lo/-Treg占CD4+ T淋巴细胞的百分比为(4.36±1.21)%,MLC中CD4+CD25+ Treg抑制同种异体T淋巴细胞增殖功能低下,与其Treg分泌TGF-β减少相关,CD4+ Treg含量及功能均低于健康志愿者(P<0.05).AS患者外周血中CD4+CD25+CD127lo/- Treg水平与TGF-β呈正相关,与TNF-α呈负相关.结论 AS患者外周血中Treg表达水平低,且存在功能缺陷,导致体内诱导免疫耐受机能不足,可能参与AS免疫发病.

The alteration of CD4+ regulatory T cells in patients with ankylosing spondylitis

Objective To evaluate the alteration of CD4+ regulatory T cells in peripheral blood from patients with ankylosing spondylitis(AS). Methods Seventy-eight AS patients and 50 healthy individuals were included in this study. The proportion of CD4+CD25+CD127lo/- T cell population in CD4+ T cells as well as that cytotoxic T lymphocytes(CTL) and NK cells in lymphocytes was evaluated by flow cytometry. Serum TGF-β and TNF-α were measured by ELISA. The inhibitory function of CD4+CD25+ regulatory T cells was measured by mixed lymphocyte culture. Results The population of CD4+CD25+CD127lo/- T cells in peripheral blood of AS patients accounted for (4.36±1.21)% of CD4+ T lymphocytes, which was significantly lower than that in healthy individuals (P<0.05). The CD4+CD25+CD127lo/- T cells population in AS patients was positively correlated with TGF-β level, but negatively with TNF-α. Compared with healthy individuals, the function of CD4+CD25+ regulatory T cells in the inhibition of alloreactive T cells was lower in AS patients, which was related to the decreased secretion of TGF-β. Conclusion The CD4+ regulatory T cells in peripheral blood of AS patients are significantly decreased and its function is defective, which leads to immune regulatory dysfunction in vivo. It may be one of immune pathogenesis mechanisms of AS.