Abstract： 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.