类风湿关节炎外周血中记忆B细胞比例与骨侵蚀的相关性研究

Correlation between memory B cells and bone erosion in rheumatoid arthritis

目的探索RA患者外周血记忆B细胞分布特征及其分布和骨侵蚀的关系,进一步了解B细胞在RA发病中的作用机制。方法采用流式细胞仪检测200例RA患者和50名健康对照外周血的B细胞亚群分布,根据表面标记将B细胞分为CD19+CD27+IgD-转换后记忆B细胞、CD19+CD27+IgD+转换前记忆B细胞、CD19+CD27-lgD-双阴记忆B细胞和CD19+CD27-IgD+幼稚B细胞,分析RA中B细胞亚群的分布特征,以及不同疾病活动度、病程及治疗下B细胞亚群分布的改变。根据关节超声结果将RA患者分为无骨侵蚀、手骨侵蚀、膝骨侵蚀及手和膝均骨侵蚀4组,分析B细胞各亚群分布、自身抗体和RA骨侵蚀的关系。采用独立样本t检验、Mann-Whitney U检验及χ^(2)检验进行组间比较,多组比较采用单因素方差分析或Kruskal-Wallis检验,采用Spearman秩相关分析进行相关性分析。结果①RA患者外周血中转换前记忆B细胞[(9.5±6.7)%]的比例低于健康对照[(12.1±4.7)%](t=2.46,P=0.015),而双阴记忆B细胞[(3.8±2.5)%]的比例高于健康对照[(2.7±1.3)%](t=-4.74,P<0.001)。②相比于疾病缓解组RA患者,中度活动组[(8.4±4.7)%与(12.4±7.5)%,t=3.13,P=0.001]和重度活动组[(7.8±7.6)%与(12.4±7.5)%,t=3.00,P=0.003]RA患者转化前记忆B细胞均降低,而重度活动组RA患者幼稚B细胞比例升高[(70.3±15.0)%与(63.9±14.6)%,t=-2.15,P=0.034]。不同病程的RA患者B细胞亚群分布差异无统计学意义。③接受激素治疗的RA患者总B细胞[(4.8±2.9)%与(7.2±4.1)%,t=-3.24,P=0.001]、转化前记忆B细胞[(7.6±4.3)%与(10.0±7.1)%,t=-2.63,P=0.010]显著低于未接受激素治疗患者,而双阴记忆B细胞[(4.9±3.0)%与(3.6±2.3)%,t=-2.79,P=0.006]显著高于未接受激素治疗患者。④相比于无骨侵蚀组RA患者,手和膝均骨侵蚀组的RA患者外周血中转换前记忆B细胞[6.8%(2.5%,9.5%)与9.7%(5.5%,17.5%),Z=-2.12,P=0.034]比例显著降低。相比于无骨侵蚀组RA患者,双阴记忆B细胞在膝骨侵蚀组RA患者[3.3%(2.7%,5.0%)与2.6%(1.9%,3.8%),Z=-2.09,P=0.036]及手和膝均骨侵蚀组RA患者[3.9%(2.3%,5.6%)与2.6%(1.9%,3.8%),Z=-2.41,P=0.016]中的比例均显著升高。另外,手和膝骨侵蚀组RA患者中RF水平显著高于无骨侵蚀组RA患者[141.0(38.0,874.0)U/ml与53.5(10.0,106.0)U/ml,Z=-2.07,P=0.039];手骨侵蚀组RA患者中ACPA阳性患者的比例高于无骨侵蚀组RA患者[81%(52/64),与64%(38/59),χ^(2)=4.44,P=0.043]。结论RA患者外周血中双阴记忆B细胞升高、转换前记忆B细胞降低及高水平的自身抗体可能与RA骨侵蚀密切相关,可能为RA致残的发病机制之一。

Objective To explore the distribution characteristics of memory B cells and its relationship with bone erosion in patients with rheumatoid arthritis(RA),and to further understand the mechanism of B cells in the pathogenesis of RA.Methods B cell subsets in peripheral blood of 200 RA patients and 50 healthy individuals were detected by flow cytometry.According to the surface markers CD19,CD27 and lgD,B cells were divided into CD19+CD27+lgD-switched memory B cells,CD19+CD27+lgD+non-switched memory B cells,CD19+CD27-lgD-double-negative memory B cells and CD19+CD27-lgD+naive B cells.B cells in RA patients with various disease activity score,course of disease and treatment were analyzed.Patients were divided into four groups according to the results of joint ultrasonography,including patients without bone erosion,patients with hand bone erosion,patients with knee bone erosion and patients with hand and knee bone erosion.The relationship between the distribution of B cell subsets,autoantibodies and RA bone erosion were analyzed.Differences between the groups were analyzed by independent-samples t test,Mann-Whitney U test andχ^(2) test.The analysis of variance,Kruskal-Wallis analysis were used for multi-group comparison,Spearman correlation analysis was also used for correlation analysis.Results①RA patients showed significantly decreased non-switched memory B cells[(9.5±6.7)%vs(12.1±4.7)%,t=2.46,P=0.015]and increased double negative memory B cells[(3.8±2.5)%vs(2.7±1.3)%,t=-4.74,P<0.001]in comparison to healthy individuals.The percentage of non-switched memory B cells were decreased in RA patients with moderate disease activity[(8.4±4.7)%vs(12.4±7.5)%,t=3.13,P=0.001]and high disease activity[(7.8±7.6)%vs(12.4±7.5)%,t=3.00,P=0.003]in comparison to those in RA patients who achieved remission.Meanwhile,the naïve B cells[(70.3±15.0)%vs(63.9±14.6)%,t=-2.15,P=0.034]were increased in RA patients with moderate disease activity.No difference was found in RA patients with different disease courses.Total B cells[(4.8±2.9)%vs(7.2±4.1)%,t=-3.24,P=0.001],non-switched memory B cells(7.6±4.3)%vs(10.0±7.1)%,t=-2.63,P=0.010)in RA patients who received prednisone treatment were decreased,while double-negative memory B cells(4.9±3.0)%vs(3.6±2.3)%,t=-2.79,P=0.006]were increased compared with those in RA patients without prednisone treatment.Non-switched memory B cells was decreased in RA patients with hand and knee erosion compared with RA patients without erosion[6.8%(2.5%,9.5%)vs 9.7%(5.5%,17.5%),Z=-2.12,P=0.034].Double negative memory B cells in subgroup with keen erosion[3.3%(2.7%,5.0%)vs 2.6%(1.9%,3.8%),Z=-2.09,P=0.036]as well as with hand and knee erosion[3.9%(2.3%,5.6%)vs 2.6%(1.9%,3.8%),Z=-2.41,P=0.016]were higher than those in patients without erosion.In addition,higher serum RF level was found in subgroup RA patients with hand and knee erosion compared with subgroup of RA patients without erosion[141.0(38.0,874.0)U/ml vs 53.5(10.0,106.0)U/ml,Z=-2.07,P=0.039].Meanwhile,the positive rate of ACPA in RA patients with bone erosion of hand was significantly higher than that of RA patients without bone erosion[81%(52/64)vs 64%(38/59),χ^(2)=4.44,P=0.043).Conclusions The results suggest that the increase of double negative memory B cells,the decrease of non-switched memory B cells and higher level of autoantibodies may closely relate to bone erosion of RA,which may be one of the pathogenesis of disability in RA.