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 < 0.01）, as well as between the IL-13Rα1 mRNA expression and its methylation level （r = -0.84, P < 0.01）. Conclusion The development of SLE may be related to the overexpression of IL-13Rα1 gene induced by DNA hypomethylation in T cells.

Key words: Systemic Lupus Erythematosus, IL-13R&alpha, 1, Methylation, T cells