成人隐匿性自身免疫糖尿病CD4+调节性T细胞研究

目的 观察成人隐匿性自身免疫糖尿病(LADA)患者CD4+CD25+T细胞和CD4+ T细胞的FOXP3 mRNA表达,探讨其免疫学的发病机制.方法 LADA患者67例,2型糖尿病30例,正常对照30例,通过流式细胞术检测CD3+、CD4+、CD8+、CD4+ CD25+ T细胞阳性细胞百分率.采用磁珠分离CD4+T细胞,用实时-PCR方法,半定量检测CD4+T细胞的FOXP3 mRNA表达水平.结果 LADA患者比正常对照组,CD4+CD25+T细胞升高(4.1±1.9 vs 2.8±1.5,P＜0.01),CD4+CD25+T细胞占CD4+T细胞的比例升高(11.9±5.0 vs 8.2±3.7,P＜0.01).LADA患者CD4+T细胞FOXP3 mRNA的表达水平明显降低(0.52-fold,P＜0.01,n=10).结论 LADA患者存在调节性T细胞抑制功能缺陷.

Decrease of FOXP3 mRNA in CD4+ T cells in latent autoimmune diabetes in adult

OBJECTIVE: To study the percentage of peripheral blood CD4(+)CD25(+) T cells and the expression of FOXP3 mRNA in the patients with latent autoimmune diabetes in adult (LADA). METHODS: Fresh peripheral blood samples were obtained from 60 patients with LADA, 30 patients with type 2 diabetes and 30 age- and sex-matched matched healthy nondiabetic control subjects without diabetic family history. Two-color staining (anti-CD4, anti-CD25, anti-CD3, and anti-CD8) flow cytometric analysis was employed to measure the CD4(+)CD25(+) T cells. The CD4 positive human cells were isolated with immunomagnetic beads, and then real time-PCR was used to test the expression of FOXP3 mRNA in the CD4(+) T cells. RESULTS: In the LADA group, the percentage of CD4(+)CD25(+) T cells was 4.1 +/- 1.9, significantly higher than that of the normal control group (2.8 +/- 1.5, P < 0.01), the ratio of CD4(+)CD25(+) to the CD4(+) T cells was 11.9 +/- 5.0, significantly higher than that of the normal control group (8.2 +/- 3.7, P < 0.01), the percentage CD8(+) T cells was 24.6 +/- 6.8, significantly higher than that of the normal control group (19.4 +/- 7.1, P < 0.01) and the CD4(+)/CD8(+) ratio was 1.5 +/- 0.5, significantly lower (1.9 +/- 0.6, P < 0.01). The expression of FOXP3 mRNA in CD4(+) T cells of the LADA group was 0.52 time that of the control group (P < 0.01). The CD4(+)/CD8(+) ratio of LADA group was significantly lower that of the type 2 diabetes group (1.8 +/- 0.8, P < 0.05), however, the other results were not significantly different between these 2 groups. The percentage of was positively correlated with the titer of glutamic acid decarboxylase antibody (GADA) (r = 0.292, P < 0.05). CONCLUSION: Though the percentage of CD4(+)CD25(+) T cells and the level of CD25 expression in CD4(+) T cells are elevated, the expression of FOXP3 mRNA in CD4(+) T cells is lower. in the patients with LADA. The regulatory T cells may have defective suppressor function in patients with LADA.