目的：探讨趋化因子配体19（C-C chemokine ligand 19，CCL19）在类风湿关节炎（rheumatoid arthritis，RA）患者血清中的表达水平及临床意义。方法：采用酶联免疫吸附测定检测RA患者和健康对照血清CCL19的表达水平，收集患者临床及实验室资料，利用流式细胞术检测患者外周血B细胞及记忆B细胞亚群的比例。对比不同临床特征的RA患者血清CCL19表达差异，分析血清CCL19水平与临床及实验室指标、B细胞及记忆B细胞亚群间的相关性。数据分析采用独立样本t检验、配对t检验、Pearson和Spearman相关分析。结果：RA患者血清中高表达CCL19（P<0.001），治疗后的RA患者CCL19表达显著降低（P<0.001）。CCL19与红细胞沉降率（erythrocyte sedimentation rate，ESR）、C反应蛋白（C-reactive protein，CRP）、28个关节的疾病活动度评分（disease activity score in 28 joints，DAS28）无相关性（P>0.05），但与类风湿因子（rheumatoid factor，RF）、抗环瓜氨酸多肽（cyclic citrullinated peptide，CCP）抗体水平显著相关（r=0.42，P=0.002；r=0.33，P=0.013）；CCL19水平在抗CCP抗体阳性组显著高于抗CCP抗体阴性组，RF阳性组显著高于RF阴性组，高、低疾病活动组间以及早期和非早期RA组间差异均无统计学意义；CCL19与外周血CD19+、CD27+、D27-、CD27+IgD+、CD27+IgD-、CD27-IgD+、CD27-IgD- B细胞的比例均未见显著相关性（P>0.05）。相较于健康对照，RA患者外周血CD27+IgD+、CD27+IgD-、CD27+ B细胞比例均显著减少。结论：血清CCL19水平可以反映RA患者的免疫活动状态，可预判RA患者B细胞抗体分泌的功能状态，从而可能指导RA临床治疗策略的选择。

Objective：To investigate the serum level of C-C chemokine ligand 19 (CCL19) and its clinical significance in rheumatoid arthritis. Methods: The serum CCL19 levels in both rheumatoid arthritis (RA) patients and health controls were detected by ELISA. The proportion of peripheral blood B cells and memory B cell subsets were also detected in some patients. Then the clinical and laboratory data of the patients were collected. The CCL19 levels in patients with different clinical features were analyzed. And the correlation between the clinical data, laboratory parameters, B cell subsets proportion and serum CCL19 levels were also analyzed. Independent samples t test, paired t test, Pearson and Spearman correlation were used for statistical analysis. Results: The levels of CCL19 was higher in the RA patients than the health controls (P<0.05). The serum CCL19 levels were decreased in the RA patients who accep-ted disease-modifying anti-rheumatic drugs (DMARDs) treatment for 6 months (P<0.001). Serum CCL19 levels were correlated with the titers of both rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibody (r=0.42, P=0.002; r=0.33, P=0.013), but not with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and disease activity score in 28 joints (DAS28) (P>0.05). The levels of CCL19 were higher in the serum positive (RF and anti-CCP antibody) patients, but there were no differences between low and high disease activity RA, as well as early and non-early RA. There was no correlation between the serum CCL19 levels and the proportion of B cells as well as memory B subsets. All the proportion of peripheral blood CD27+ memory B cell subsets in RA was lower than the healthy controls, including CD27+IgD+, CD27+IgD- and CD27+ B cells. Conclusion: The increased serum CCL19 levels in RA patients are associated with the activity of B cells, so CCL19 might predict whether the RA type is a B cell mediated RA, and specify the treatment directions for the rheumatologist.