系统性血管炎中抗内皮细胞抗体的检测及其靶抗原研究

Prevalence of antiepithelial call antibody in systemic vasculitis and identification of the target antigen thereof

目的检测抗内皮细胞抗体(AECA)在系统性血管炎中阳性率,探讨其可能致病机制.方法实验组选取113例系统性血管炎患者,对照组为57例系统性红斑狼疮(SLE)、15例类风湿关节炎(RA)及20名正常人.提取EA.hy926内皮细胞株蛋白质,免疫印迹法检测以上各组患者血清中AECA阳性率,进而应用双向电泳结合免疫印迹法、液相色谱-电喷雾离子阱质谱(LC-ESI-MS/MS)分析,分离和鉴定AECA靶抗原.结果免疫印迹法检测结果显示,系统性血管炎、SLE患者AECA阳性率明显高于RA患者及正常对照组(P<0.01):系统性血管炎组AECA阳性率为69.0%(78/113) ,SLE和RA患者AECA阳性率为分别66.7% (38/57)、6.7%(1/15),20名正常人血清中均未检出AECA;系统性血管炎患者AECA主要识别的蛋白质相对分子质量为26 000～125 000,SLE患者主要识别的蛋白质相对分子质量为15 000～97 000.47000-AECA常见于AECA阳性的不同系统性血管炎和SLE患者血清中,经蛋白组学方法分离鉴定,其成分为α-烯醇化酶.结论不同的系统性血管炎和SLE患者血清中均有较高的AECA阳性率,AECA为一组与内皮细胞多种蛋白相结合的异质性抗体;不同系统性血管炎和SLE患者的AECA可能存在有共同的靶抗原(47 000 内皮细胞蛋白质),其成分为α-烯醇化酶.

Objective To investigate the prevalence of antiepithelial cell antibody （AECA） in systemic vasculitis （SV） and the target antigen thereof. Method Sera of 113 patients with SV of different kinds, 46 patients with Behcet＇s disease, 23 patients with Takayasu arteritis, 19 patients with Wegener＇s granulomatosis, 8 patients with polyarteritis nodosa, 7 patients with microscopic polyangiitis, and 10 patients with Churg-Strauss syndrome were collected to detect the protein expression of AECA by Western blotting, with the protein of the endothelial cells of the line EA. hy926 line as substrate. Two-dimensional electrophoresis combined with immunoblotting, liquid chromatography-electrospray ionization mass spectrography was used to detect the target antigens related to vasculitis. Sera of 57 patients with systemic lupus erythematosus （SLE）, 25 patients with rheumatoid arthritis （RA）, and 20 healthy persons were collected as controls. Results The AECA-positive rate of the SV patients was 69. 0%, not significantly different from that of the SLE patients （ 66. 7% ）, but significantly higher than those of the RA patients （6. 7% , P 〈0.01 ） and healthy persons （0, P 〈0. 01 ）. The AECA from the SV patients reacted with the endothelial cell （EC） antigens with the molecular size of 26 to 125 kDa, and the AECA from the SLE patients reacted with the EC antigens with the mnlecular size of 15 to 97 kDa. The EC antigens with the molecular size of 47 kDa was commutly found in the sera of the AECA-positive SV patients and SLE patients, however, was not found in the RA, and polymyositis-dermatomyositis patients. The EC protein reacted by 47 kDa protein was identified by proteomic techniques as ct-enolase. Conclusion A group of heterogeneous antibodies, AECA can be round frequently in patients with SV and SLA. AECA reacts against a common EC antigen, α-enolase.