白细胞介素35＋调节性B细胞在系统性红斑狼疮患者外周血中的表达

Expression of interleukin-35＋ regulatory B cells in peripheral blood of patients with systemic lupus erythematosus

目的：检测系统性红斑狼疮（SLE）患者外周血白细胞介素35^＋调节性B细胞（IL-35^＋Bregs）的表达，并探讨其在SLE发病机制中的作用。方法以2015年1月至2016年1月就诊于本院风湿免疫科的SLE患者50例为研究对象，按SLE活动指数（SLEDAI）分为活动期SLE组（n=30）和稳定期SLE组（n=20）。以同期健康志愿者20例作为正常对照组。分离外周血单个核细胞（PBMC）进行培养，流式细胞术检测各组外周血IL-35^＋CD19^＋Bregs和CD4^＋CD25^＋FOXP3^＋调节性T细胞（Tregs）表达，酶联免疫吸附法（ELISA）检测细胞培养上清液IL-35水平。结果流式细胞术检测显示，活动期SLE组、稳定期SLE组和正常对照组外周血IL-35^＋CD19^＋Bregs表达分别为（1.43±0.67）％、（2.27±0.68）％、（4.24±1.11）%，组间两两比较差异均具有统计学意义（均P〈0.01）；活动期SLE组、稳定期SLE组和正常对照组外周血CD4^＋CD25^＋FOXP3^＋ Tregs表达分别为（2.26 ±0.49）％、（3.82 ±0.94）％、（5.77±1.09）％，组间两两比较差异均具有统计学意义（均P〈0.01）。活动期SLE组、稳定期SLE组外周血IL-35^＋CD19^＋Bregs和CD4^＋CD25^＋FOXP3^＋Tregs表达均低于正常对照组，且活动期SLE组均低于稳定期SLE组。活动期SLE组、稳定期SLE组和正常对照组细胞培养上清液IL-35水平分别为（5.48±1.68）pg/ml、（7.74±1.26）pg/ml、（11.96±1.67）pg/ml，组间两两比较差异均具有统计学意义（均P〈0.01）。活动期SLE组细胞培养上清液IL-35水平低于稳定期SLE组和正常对照组。SLE患者外周血IL-35^＋CD19^＋Bregs表达与CD4^＋CD25^＋FOXP3^＋Tregs表达呈正相关（r=0.813，P〈0.01），SLE患者外周血IL-35^＋CD19^＋Bregs表达、CD4^＋CD25^＋FOXP3^＋Tregs表达与细胞培养上清液IL-35水平均呈正相关（r=0.862、0.811，均P〈0.01）。结论 IL-35^＋Bregs可能通过分泌IL-35参与了SLE的发病。

Objective To investigate the expression of interleukin-35^＋regulatory B cells（IL-35^＋Bregs） in peripheral blood of patients with systemic lupus erythematosus （SLE）,and its role in the pathogenesis of SLE. Methods Fifty SLE patients treated in our Department of Rheumatology and Immunology between January 2015 and January 2016 were included in this study. According to the SLE disease activity index（SLEDAI）,the patients were assigned to active SLE group（n=30）and stable SLE group （n=20）. A contemporary cohort of 20 healthy volunteers was recurited as normal control group. Peripheral blood mononuclear cells（PBMCs）were isolated from these subjects and cultured. Flow cytometry was used to examine the expression of IL-35^＋CD19^＋Bregs and CD4^＋CD25^＋FOXP3^＋regulatory T cells（Tregs） in the peripheral blood of each group. Enzyme-linked immunosorbent assay（ELISA）was used to detect IL-35 levels in supernatant of the cell culture. Results Flow cytometry showed that：（1）the expression levels of peripheral blood IL-35^＋CD19^＋Bregs in active SLE group,stable SLE group and normal control group were （1.43 ± 0.67）%,（2.27 ± 0.68）% and（4.24 ± 1.11）%,respectively,with statistically significant difference between any of two groups（all P〈0.01）;（2）the expression levels of peripheral blood CD4^＋CD25^＋FOXP3^＋Tregs in active SLE group,stable SLE group and normal control group were（2.26±0.49）%,（3.82±0.94）%and（5.77 ± 1.09）%,respectively,with statistically significant difference between any of two groups（all P〈0.01）. The expression levels of peripheral blood IL-35^＋CD19^＋ Bregs and CD4^＋CD25^＋FOXP3^＋ Tregs were lower in active SLE group and stable SLE group than those in the normal control group,and lower in active SLE group than those in stable SLE group. The IL-35 levels in cell culture supernatant in active SLE group, stable SLE group and normal control group were（5.48 ± 1.68）pg/ml,（7.74 ± 1.26）pg/ml and（11.96 ± 1.67） pg/ml,respectively,with statistically significant difference between any of two groups （all P〈0.01）. Cell culture supernatant IL-35 level was lower in active SLE group compared with stable SLE group and normal control group. In the peripheral blood of SLE patients,the expression of IL-35^＋CD19^＋Bregs was positively correlated with expression of CD4^＋CD25^＋FOXP3^＋Tregs（r=0.813,P〈0.01）,and the expressions of IL-35^＋CD19^＋ Bregs and CD4^＋CD25^＋FOXP3^＋ Tregs were positively correlated with IL-35 level in cell culture supernatant （r=0.862 and 0.811,both P〈0.01）. Conclusion IL-35 ＋ Bregs may be involved in the pathogenesis of SLE via secretion of IL-35.