抗髓过氧化物酶抗体IgG亚型在丙基硫氧嘧啶引起的小血管炎中的分布及其意义

Distribution of IgG subclass of anti-myeloperoxidase antibodies in sera from patients with propylthiouracil induced vasculitis

目的 观察丙基硫氧嘧啶 (PTU)引起的抗中性粒细胞胞浆抗体 (ANCA)相关小血管炎患者活动期和缓解期血清中抗MPO抗体IgG亚型的分布并探讨其意义。方法 以 12例PTU引起的ANCA相关小血管炎患者为研究对象 ,收集患者未治疗的活动期血清 ,其中 10例同时具有缓解期的血清 ,应用抗原特异性ELISA法检测抗MPO抗体总IgG及各IgG亚型的滴度 ,比较其与原发性小血管炎中抗MPO抗体IgG亚型分布的异同。结果 与原发性血管炎不同 ,所有PTU引起的ANCA相关小血管炎患者血清中均未检测到IgG3亚型。其他亚型在活动期的检测结果分别为IgG1( 12 / 12例 ,10 0 % ) ,IgG2 ( 8/ 12例 ,6 6 .7% ) ,IgG4 ( 7/ 12例 ,5 8 3% ) ;缓解期各亚型的检测结果分别为IgG1( 9/ 10例 ,90 % ) ,IgG2 ( 4 / 10例 ,4 0 % ) ,IgG4 ( 2 / 10例 ,2 0 % )。与原发性小血管炎缓解期中IgG4仍保持较高水平的现象不同 ,经停用PTU及应用免疫抑制治疗病情缓解后 ,IgG4亚型的滴度显著下降甚至转阴。结论 PTU引起的抗MPO抗体IgG亚型的分布与原发性小血管炎并不一致。

Objective To investigate the distribution of IgG subclass of anti myeloperoxidase (MPO) antibodies, a kind of antineutrophil cytoplasmic autoantibody (ANCA), in sera from patients with propylthiouracil (PIU) induced vasculitis. Methods Serum samples were collected from 12 patients with PIU induced MPO ANCA positive vasculitis, both sera of active and remission phases were collected from 10 of which, and only serum of active phase was collected from 2 of which. Anti MPO IgG subclasses were detected by antigen specific ELISA. The distribution of anti MPO IgG subclasses in PIU induced vasculitis was compared with that in primary vasculitis. Results Anti MPO IgG3 subclass was not detected in the sera from both active and remission phases of PIU induced vasculitis. In the active phase the following anti MPO IgG subclasses were found: IgG1 (12/12, 100%), IgG2 (1/12, 66.7%), and IgG4 (7/12, 58.3%). In the remission phase, the following anti MPO IgG subclasses were found: IgG1 (9/10, 90%), IgG2 (4/10, 40%), and IgG4 (2/10, 20%). The titer of anti MPO IgG4 subclass remained high in the remission phase in primary vasculitis; however, it decreased significantly after the cessation of PIU use in PIU induced vasculitis. Conclusion The distribution of anti MPO IgG subclasses in the sera of the patients with PIU induced vasculitis is different from that of the patients with primary vasculitis. The higher titer pf MPO ANCA in the sera of the patients with PIU induced vasculitis may be associated with the repeated PIU stimulation.