抗线粒体抗体M2亚型IgG和IgA在原发性胆汁性肝硬化诊断中的作用

目的 评价以新型天然M2抗原和BPO融合蛋白M2-3E(BPO)为靶抗原的酶联免疫吸附(ELISA)法(抗-M2-3E ELISA)检测抗线粒体抗体M2亚型(AMA-M2)IgG和IgA抗体在原发性胆汁性肝硬化(PBC)诊断中的敏感性、特异性以及其临床意义.方法 分别用间接免疫荧光法(IFL)、以丙酮酸脱氢酶复合体为靶抗原的ELISA法(抗-PDC ELlSA),抗-M2-3E ELISA法检测107例PBC患者,87例疾病对照患者和26名健康体检者的AMA-M2 IgG和(或)IgA抗体.检测ALT,AST,总胆红素、白蛋白、Y-谷氨酰转肽酶、碱性磷酸酶、血清肌酐、IgG、IgM及IgA.对于符合正态分布的计量数据采用t检验,不符合正态分布者采用秩和检验. 结果 107例PBC患者抗-M2-3E ELISA法AMA-M2 IgG的检出率(90.6%)高于IFL法(81.3%)和抗-PDCELISA法(72.9%),t值分别为4.32和6.03,P值均<0.05.抗M2-3E ELISA法检测AMA-M2 IgA的检出率为55.1%,特异性为97.2%,而总体AMA-M2 IgG和(或)IgA的检出率为92.5%,特异性为95.2%.20例IFL检测AMA-M2 IgG为阴性的PBC患者中,抗-M2-3E ELISA法检出率为45%,AMA-M2 IgG和(或)IgA的检出率为55%,抗-M2-3E ELISA可以在超过一半的IFL阴性的患者中检出AMA-M2 IgG和(或)IgA.AMA-M2 IgG呈阳性的患者(97例)比呈阴性的患者(10例)有更加严重的组织学变化和更高的IgG,IgM和碱性磷酸酶水平.结论 抗-M2-3E ELISA法具有比IFL和抗-PDC ELISA法更高的敏感性和特异性,可作为第一轮AMA-M2的筛查.AMA-M2 IgG阳性可能说明该PBC患者有更加严重的疾病,但是AMA-M2 IgG和IgA都不能单独用于诊断PBC.

The significance of antimitochondrial IgA and IgG in the diagnosis of primary biliary cirrhosis

Objective To evaluate the sensitivity and the specificity of Anti-M2-3E ELISA for the detection of lgG-and IgA-specific isotypes of antimitochondrial antibody(AMA),and to investigate the significance of antimitochondriai IgA and IgG in the diagnosis of primary biliary cirrhosis(PBC).Methods Sera were collected from 107 PBC patients,87 disease controls and 26 healthy controls,and the antimitochondrial antibodies(IgG and IgA)were detected using indirect immunofluorescence(IFL),AntiPDC ELISA and Anti.M2-3E ELISA.Results The AMA IgG positive rate in PBC patients was 90.6% detected by Anti-M2-3E ELISA,which is significantly higher than that(81.3%)detected by IFL(t=4.32,P<0.05)and that(72.9%)detected by Anti-PDC ELISA (t=6.03,P<0.05).The AMA IgA was positive in 59 of the 107 PBC patients.and 99 of the 107 patients were positive for AMA IgG or/and IgA.9 of the 20 IFL-negative patients were positive for AMA IgG as indicated by Anti-M2-3E ELISA.11 of the 20 IFL-negative patients were positive for AMA IgG or/and IgA as indicated Anti-M2-3E ELISA.Compared to patients negative for IgG AMA,patients positive for lgG AMA had more severe histopathology and higher levels of ALP,IgG,and lgM.Conclusion The IgG and IgA Anti-M2-3E ELISAs ale more sensitive for the AMA detection than IFN and the Anti-PDC ELISA.The presence of AMA IgG is the characteristics of severe PBC.