羟氯喹逆转紫外线诱导的SLE患者CD4+T细胞DNA低甲基化的研究

目的 探讨羟氯喹对紫外线诱导的SLE患者CD4+ T细胞基因组DNA低甲基化的作用。方法 选择SLE患者组30例，正常人对照组10例。 磁珠分选SLE患者组和正常人对照组外周血CD4+ T细胞，311 nm窄谱UVB照射，加入羟氯喹共培养，检测各组间基因组DNA甲基化表达水平。结果 SLE患者组CD4+ T细胞DNA甲基化水平（3.922 ± 2.215）%低于正常人对照组［（10.210 ± 5.573）%，t = 3.450，P = 0.026］；SLE活动组患者CD4+ T细胞经45 mJ/cm2和100 mJ/cm2 UVB照射后DNA甲基化水平为（1.784 ± 1.033）%和（1.932 ± 1.844）%，均显著低于活动期患者未照射组［（3.922 ± 2.215）%，t = 3.000、4.118，P值均 < 0.05］。经100 mJ/cm2 UVB照射后，活动期患者DNA甲基化水平（1.932 ± 1.844）%显著低于稳定期患者照射组 ［（7.235 ± 3.846）%，t = 2.648，P < 0.05］和正常人对照组［（5.472 ± 5.573）%，t = 3.000，P < 0.05］。SLE活动组T细胞经45和100 mJ/cm2 UVB照射后，加用羟氯喹结果DNA甲基化水平为（4.698 ± 1.948）%和（8.698 ± 3.151）%，均比照射未加羟氯喹组显著升高（t = 4.827、3.184，P值均 < 0.05）；经45 mJ/cm2 UVB照射前后均加羟氯喹组DNA甲基化水平（5.404 ± 2.308）%比照射未加羟氯喹组（1.784 ± 1.033）%显著升高，t = 4.827，P < 0.01。结论 羟氯喹可以逆转紫外线诱导的SLE患者CD4+ T细胞DNA低甲基化，羟氯喹对活动期SLE患者更为明显。

Hydroxychloroquine reverses ultraviolet ray-induced genomic DNA hypomethylation in CD4+ T cells from patients with systemic lupus erythematosus

Objective To explore the effect of hydroxychloroquine on ultraviolet ray-induced genomic DNA hypomethylation in CD4+ T cells from patients with systemic lupus erythematosus (SLE). Methods Thirty patients with SLE and 10 normal human controls were enrolled in the study. CD4+ T cells were isolated from these subjects by using magnetic beads, and cultured. Hydroxychloroquine of 50 mg/L was added to the culture medium of CD4+ T cells before or after the exposure to narrow band ultraviolet B (NB-UVB) 311 nm.After additional culture, the levels of genomic DNA methylation in CD4+ T cells were determined with the Imprint Methylated DNA Quantification kit. Results The levels of DNA methylation was lower in SLE patients than in the normal controls [(3.922 ±2.215)% vs. (10.210 ± 5.573)%, t= 3.450, P = 0.026]. After exposure to UVB at 45 and 100 mJ/cm2, the DNA methylation level in patients with active SLE decreased from (7.235 ±3.846)% to (1.784 ± 1.033)% and (1.932 ± 1.844)% respectively (t= 3.000, 4.118, both P< 0.05). Decreased DNA methylation level was observed in CD4+ T cells from patients with active SLE compared with those from patients with stable SLE and normal human controls [(1.932 ± 1.844)% vs. (7.235 ± 3.846)% and (5.472 ±5.573)%, t = 2.648, 3.000, both P< 0.05] after irradiation with UVB of 100 mj/cm2. A significant increase in the methylation level was observed in active SLE patient-derived CD4+ T cells treated with hydroxychloroquine following the irradiation with UVB of 45 (4.698% ± 1.948%) and 100 mJ/cm2(8.698% ± 3.151%) compared with those only treated with UVB irradiation (t = 4.827, 3.184, both P< 0.05), as well as in those treated with hydroxychloroquine before and after the irradiation with UVB of 45 mJ/cm2 compared with those receiving irradiation alone [(5.404 ± 2.308)% vs. (1.784 ± 1.033)%, t = 4.827, P< 0.01]. Conclusion Hydroxychloroquine can reverse the UVB-induced genomic DNA hypomethylation in CD4+ T cells from patients with SLE,especially in those from patients with active SLE.