Objective: To evaluate the applicability of limiting antigen avidity enzyme immunoassay (LAg-Avidity EIA, LAg for short) in determining the new HIV-1 infection status of MSM population with seroconversion and make correlation analysis of other biological indicators. Methods: The 15 cases with HIV seroconversion were found in a MSM observation cohort for calculating the HIV prevalence in Zhejiang.The subjects were conducted epidemiological investigation and sampled.The interval of infection time was estimated according to the exposure history and the time of HIV-positive confirmation.LAg, immunoblotting, CD4 cell counting and viral load test were applied in the testing of the related blood samples. McNermar test was conducted for consistency of the two methods. Results: Of 15 cases, the average age was (31.5±8.0) years old, ranging from 24 to 57 years old. The interval of infection time ranged from 40 days to 366 days, and the median was 134 days, with inter-quartile range from 89 to 180 days. A total of 7 cases were classified as new HIV-1 infection by LAg, and 8 cases were classified as chronic infection.The consistent rate was high to 86.67%, and kappa value was 0.73.The samples lacking at least two bands in p31, p51, p66 and gp120 by immunoblotting were determined as recent infection, of which the new infection proportion was significantly higher than that of other samples (P=0.029).There was no statistical difference in the distribution of CD4 counts (P=0.533) and viral loads (P=0.467) between the new infection and chronic infection groups that divided by LAg. Conclusion: By combining with exposure history, the limiting antigen avidity enzyme immunoassay can be used to estimate the new HIV-1 infection.The other biological indicators such as immunoblotting bands, CD4 cell counts and viral loads, can be used as accessory indicators in evaluating the status of new HIV-1 infection.
目的： 利用限制性抗原亲和力酶免法对男男性行为人群（MSM）HIV阳转病例进行新发感染的估判，并对其他生物学指标进行关联性分析。 方法： 对浙江省2019年MSM阳转率观察队列中发现的15例阳转病例进行流行病学调查，根据暴露史和确证阳性时间计算检测阳转间隔时间。使用限制性抗原亲和力酶免法（LAg-Avidity EIA）、免疫印迹法、CD4+T淋巴细胞计数和病毒载量对相应样本进行检测，分析各检测结果与新发感染估判的关联，用McNermar检验一致性。 结果： 15例病例的年龄为（31.5±8.0）岁，范围为24~57岁；HIV阳转间隔时间M（P25，P75）为134（89，180）d，最短为40 d，最长为366 d。LAg-Avidity EIA检测为新发感染的7例，长期感染的8例，与检测阳转间隔时间符合率为86.67%，kappa值为0.73。免疫印迹法条带p31、p51、p66、gp120中缺至少2个条带的样本为新发感染者的比例高于长期感染者（P=0.029）。LAg检测判定的新发感染和长期感染两组的CD4+T淋巴细胞结果（P=0.533）和病毒载量（P=0.467）差异无统计学意义。 结论： 限制性抗原亲和力酶免法结合暴露史可有效用于MSM HIV阳性病例的HIV-1新发感染的估判，免疫印迹带型、CD4+T淋巴细胞计数和病毒载量可作为估判新发感染的辅助指标。.
Keywords: Acquired immunodeficiency syndrome; HIV; Immunoblotting; Limiting antigen avidity enzyme immunoassay; Sexually transmitted diseases, viral.