SLE患者T淋巴细胞IL-13受体α1基因表达及其调节序列甲基化状态的研究

目的 研究SLE患者外周血T淋巴细胞IL-13受体α1（IL-13Rα1）基因mRNA的表达及IL-13Rα1基因调节序列甲基化状态。方法 免疫磁珠法（MACS）分离10例SLE患者和6例正常人外周血CD4+和CD8+ T细胞，采用实时荧光定量PCR检测T细胞中IL-13Rα1 mRNA的表达，并用甲基化特异性PCR（MSP）方法检测IL-13Rα1基因调节序列的甲基化水平。结果 活动期SLE患者CD4+ T细胞中IL-13Rα1 mRNA表达水平为2.224 ± 0.251，非活动期SLE患者为1.712 ± 0.132，正常人组为1.104 ± 0.044，三组间比较，差异均有统计学意义（P < 0.05）；CD8+ T细胞中IL-13Rα1 mRNA表达水平活动期、非活动期及正常人组分别为1.672 ± 0.142，1.410 ± 0.154，1.238 ± 0.106，活动期组与正常人组比较差异有统计学意义（P < 0.05），而非活动期组与正常人组、活动期组与非活动期组比较，差异均无统计学意义（P > 0.05）。CD4+ T细胞中IL-13Rα1基因甲基化指数活动期SLE患者为0.454 ± 0.023，非活动期为0.635 ± 0.065，正常人为0.844 ± 0.097，三组间比较，差异均有统计学意义（P < 0.05）；CD8+ T细胞中IL-13Rα1基因甲基化指数三组间比较，差异均无统计学意义（P > 0.05）。SLE患者外周血CD4+，CD8+ T细胞IL-13Rα1 mRNA的表达与疾病活动度（SLEDAI评分）呈正相关（r = 0.79，P < 0.01；r = 0.76，P < 0.05）；CD4+ T细胞的IL-13Rα1基因的甲基化水平与疾病活动度（SLEDAI评分）呈负相关（r = -0.89，P < 0.01）；CD4+ T细胞IL-13Rα1 mRNA表达与其调节序列的甲基化水平呈负相关（r = -0.84，P < 0.01）。结论 SLE的发生发展可能与DNA低甲基化导致SLE患者T细胞过度表达IL-13Rα1有关。

Expression and methylation status of IL-13 receptor α1 gene in peripheral T lymphocytes of patients with systemic lupus erythematosus

Objective To investigate the mRNA expression and methylation status of IL-13 receptor(IL-13R)α1 gene in peripheral T lymphocytes of patients with systemic lupus erythematosus(SLE).Methods Venous blood samples were obtained from 10 SLE patients(5 in active phase,5 in inactive phase)and 6 normal human controls.CD4+ and CD8+ T cells were isolated from these samples via magnetic activated cell sorting(MACS).Real-time quantitative PCR was used to test the mRNA expression of IL-13Rα1 gene,and methylation specific PCR to detect the methylation status.Results The expression level of IL-13Rα1 mRNA was 2.224±0.251,1.712±0.132.and 1.104±0.044 in CD4+ T cells of active SLE patients,inactive SLE patients and controls,respectively;the difference between the three groups was statistically significant(all P＜0.05).The expression level of IL-13Rα1 mRNA in CD8+T cells was significantly higher in active SLE patients than that in the normal controls(1.672±0.142 vs 1.238±0.106,P＜0.05),while no difference was noted between inactive and active SLE patients or normal controls.The methylation index of IL-13Rα1 gene was 0.454±0.023.0.635±0.065.0.844±0.097 in CD4+T cells of active SLE patients,inactive SLE patients and normal controls,respectively,and the difference between the three groups was significant(all P＜0.05),while no significant difference was observed in the methylation index in CD8+T cells among these groups(P＞0.05).The IL-13Rα1 mRNA expression in CD4+T and CD8+T cells was positively correlated with SLE disease activity index(SLEDAI)score(r=0.79,0.76,P=0.007,0.02 respectively).A negative correlation was found between the methylation level Of IL-13Rα1 in CD4+T cells and SLEDAI score(r=-0.89.P＜0.0 1).as well as between the IL-13Rα1 mRNA expression and its methylation level(r=-0.84,P＜0.0 1).Conclusion The development of SLE may be related to the overexpression of IL-13Rα1 gene induced by DNA hypomethylation in T cells.