两种戊型肝炎IgG抗体检测试剂的比较

目的比较2种国产戊型肝炎IgG抗体诊断试剂(E2-IgG和X-IgG)的特异性与敏感度。方法利用2种试剂对2006年江苏省某市普通人群的流行病调查血清标本460份和经过巢式逆转录聚合酶链式反应(nest-RT-PCR)鉴定为HEV核酸阳性的临床戊型肝炎患者血清标本72份进行平行检测,并以免疫印迹实验(Westernblot,WB)和中和单抗阻断试验进行验证。结果1.460份流行病调查血清标本中WB阳性188份。2.188份WB阳性标本中E2-IgG的检测敏感度为99.5,特异度为99.6,阳性预测值99.5,阴性预测值99.6,准确性99.6;X-IgG的检测敏感度为21.3,特异度为97.4,阳性预测值85.1,阴性预测值64.1,准确性66.3。3.E2-IgG阴、阳性A450/A620值的分布在临界值附近分界明显,小于临界值的A450/A620值取对数后呈正态分布,而阳性血清A450/A620值的高低与其WB的反应强度正相关。4.E2-IgG阳性、X-IgG阴性的血清共148份,中和单抗阻断阳性率为98,WB阳性率99.3。5.经PCR鉴定为HEV核酸阳性的急性戊型肝炎患者血清中E2-IgG敏感度98.6,X-IgG敏感度80.6(χ2=10.7,P<0.01)。结论E2-IgG在不同人群中均能较好的反映体内戊型肝炎抗体存在的真实情况。

Comparison of two diagnostic reagents to detect anti-hepatitis E virus IgG antibodies

The sensitivity and specificity of two diagnostic reagent to detect the presence of anti-hepatitis E virus IgG antibodies(E2-IgG and X-IgG) were tested in 460 serum samples taken from population undergoing an epidemiological investigation of Jiangsu province in 2006 and 72 serum samples taken from patients with hepatitis E virus(HEV) infection identified by nest RT-PCR,and the results were also confirmed with Western blot assay and the blocking test with neutralizing monoclonal antibody(mAb).It was found that the sensitivity,specificity,positive or negative prediction values as well as accuracy of E2 were 99.5%,99.6%,99.5%,99.6% and 99.6%;while those of X-IgG were 21.3%,97.4%,85.1%,64.1% and 66.3% respectively.The positive and negative A450/A620 values of E2-IgG were distinct around the cut-off value,and the log value of the A450/A620 smaller than the cut-off value showed a pattern of normal distribution,while the A450/A620 value of the positive serum correlated with the intensity of Western blot assay.In addition,the positive rates of 148 samples of positive E2-IgG but negative X-IgG as demonstrated by neutralizing mAb blocking test and Western blot assay were 98.0% and 99.3%,and the sensitivities of E2-IgG and X-IgG tested in serum samples of patients with acute HEV infection with positive HEV nucleic acid as demonstrated by PCR were 98.6% and 80.6% respectively(χ2=10.7,P<0.01).It is apparent that the diagnostic reagent E2-IgG in comparison with X-IgG,can reflect a better performance on the real condition of HEV IgG antibodies in different groups of populations.