目的 ·探讨类风湿关节炎（ rhumatoid arthritis，RA）患者 B细胞亚群特点及表没食子儿茶素没食子酸酯（ epigallocatechingallate， EGCG）对 RA患者 B细胞亚群的调节作用。方法 ·纳入年龄、性别匹配的 RA患者和健康对照各 29例，运用配对 t检验分析 2组外周血中 B细胞亚群的差异；根据 28关节疾病活动评分（ disease activity score in 28 joints，DAS28）的值将 RA患者分为活动组（2.6 ≤ DAS28<5.1）和高度活动组（ DAS28 ≥ 5.1），运用 t检验分析 2组外周血中 B细胞亚群的差异。在 0、10、100 μmol/L EGCG和 2.5 μg/L葡萄球菌 A蛋白共刺激条件下，体外培养 RA患者外周血单个核细胞， 24 h后应用实时聚合酶链反应检测 B细胞活化因子受体（B-cell-activating factor receptor，BAFF-R）的表达水平，48 h后用流式细胞术检测 B细胞亚群。结果 · RA患者的总 B细胞、未分化 B细胞、记忆 B细胞和浆母细胞占淋巴细胞比例和数量均高于健康对照 (P<0.05)，而 CD19+ IL-10+调节性 B细胞（ regulatory B cell，Breg）占淋巴细胞比例和数量与健康对照相比差异无统计学意义（ P>0.05）。10例活动组与 19例高度活动组 RA患者的总 B细胞及各 B细胞亚群（除 CD19+ IL-10+ Breg外）占淋巴细胞比例和数量的差异无统计学意义（ P>0.05），6例活动组与 12例高度活动组 RA患者 CD19+ IL-10+ Breg占淋巴细胞比例和数量的差异也无统计学意义（P>0.05）。RA患者外周血总 B细胞所占比例与 IgG型类风湿因子呈弱正相关（r0.308）。EGCG能显著提高 CD19+ IL-10+ Breg占淋巴细胞比例 (P<0.05)，且 100 μmol/L EGCG能显著降低总 B细胞中 BAFF-R mRNA的表达水平 (P0.000)；但其对未分化 B细胞、记忆 B细胞和浆母细胞占淋巴细胞比例无显著影响（ P>0.05）。结论 · B细胞可能在 RA发病中发挥辅助作用，RA患者 CD19+ IL-10+ Breg数量反馈性增加，EGCG可促进 Breg增殖，降低 BAFF-R mRNA表达水平。

Objective · To explore the characteristics of B cell subsets in rheumatoid arthritis (RA) patients and the regulation of epigallocatechingallate (EGCG) on B cell subsets in RA patients. Methods · Twenty-nine age- and sex-matched RA patients and 29 healthy controls were selected, and the difference of B cell subsets in peripheral blood between the two groups was analyzedpaired t-test. According to the value of disease activity score in 28 joints (DAS28), RA patients were divided into active group (2.6≤DAS28<5.1) and highly active group (DAS28≥5.1). The differences of B cell subsets in peripheral blood between the two groups were analyzedt test. Peripheral blood mononuclear cells were cultured in vitro under co-stimulation of 0, 10, 100 μmol/L EGCG and 2.5 μg/L staphylococcal protein A. The level of B-cell-activating factor receptor (BAFF-R) mRNA was detectedreal-time PCR after 24 h, and B cell subsets were detectedflow cytometry after 48 h. Results · The numbers and the proportions of total B cells, undifferentiated B cells,memory B cells and plasmablasts in lymphocytes of RApatients were significantly higher than those of healthy controls (P<0.05), which of CD19+ IL-10+ regulatory B cells (Breg) of RA patients were not significantly different those of healthy controls (P>0.05). There was no significant difference in the numbers and the proportions of total B cells and B cell subsets (except CD19+ IL-10+ Breg) between 10 RA patients of active group and 19 RA patients of highly active group (P>0.05). There was no significant difference in the number and the proportion of CD19+ IL-10+ Breg in lymphocytes between 6 RA patients of active group and 12 RA patients of highly active group (P>0.05). The proportion of total B cells was weakly positively correlated with IgG type rheumatoid factor (r0.308). EGCG could significantly increase the proportion of CD19+ IL-10+ Breg (P<0.05) and 100 μmol/L EGCG could significantly suppress the of BAFF-R mRNA in B cells (P0.000). However, it had no significant effect on the proportions of undifferentiated B cells, memory B cells and plasmablasts in lymphocytes (P>0.05). Conclusion · B cells may play an auxiliary role in the development of RA. The number of CD19+ IL-10+ Breg in RA patients increases as a feedback. EGCG can promote Breg proliferation and suppress BAFF-R mRNA .