HIV急性/早期感染者队列低病毒载量分布及对HIV核酸诊断的影响

Study on the distribution of low viral load among an HIV acute/recent infection cohort and its influence on the HIVnucleic acid diagnosis

目的明确低病毒载量在艾滋病病毒(HIV)感染后不同阶段的占比,低病毒载量的相关因素及对HIV感染诊断的潜在影响。方法 293例沈阳市男男性行为者HIV急性/早期感染队列2008-2019年随访获得的1 673人次病毒载量数据,分析<5 000拷贝/mL的低病毒载量者在感染后不同阶段的构成比例;分析上述感染者的人口学资料、病毒基因型以及CD4+T淋巴细胞(简称CD4细胞)计数等潜在影响因素与低病毒载量的关系,并评估低病毒载量对HIV感染诊断率的影响。结果在1 673人次病毒载量结果中,病毒载量<5 000拷贝/mL者占比17.1%;感染后不同阶段低病毒载量者占比不同,感染0.5年内占比低于其他时期(14.1%vs. 26.8%,P<0.001)。多因素Logistic回归分析显示,CD4细胞计数> 500个/mm^3与低病毒载量有关(P <0.05)。137人次蛋白印迹试验(WB)不确定的早期感染者样本中,病毒载量> 5 000拷贝/mL者占比85.4%;WB不确定联合核酸定量检测> 5 000拷贝/mL以上判断为HIV感染者,诊断HIV感染的敏感性为85.4%,将2 000拷贝/mL或者1 000拷贝/mL作为诊断阈值时,诊断HIV感染的敏感性分别提高到92.7%(P=0.053)及96.4%(P=0.002)。结论低病毒载量在HIV感染自然进程中占比较高,但在感染早期占比相对低;降低核酸定量检测的诊断阈值,可进一步提高HIV感染早期的诊断率。

Objective To elucidate the proportion of low viral load in different stages of HIV infection, determine the associated factors of low viral load and evaluate its potential impact on HIV diagnosis. Methods 1 673 person-time viral loads of 293 men who have sex with men from acute/recent HIV-1 infection cohort in Shenyang were collected during the follow-up period from 2008 to 2018. The proportion of low viral load less than 5000 copies/m L in different stages after infection was analyzed. The demographic data, virus genotype, CD4+ T cell counts were analyzed to evaluate the impact of low viral load on HIV infection diagnosis. Results Viral loads below 5000 copies/m L accounted for 17.1% of the 1 673 person-time results. The proportion of low viral loads was different in different stages after infection. And the proportion of low viral loads within 0.5 year after infection was lower than that of other periods(14.1% vs.26.8%, P < 0.001). The results of multivariate logistic regression analysis showed that CD4+ T cell counts > 500/mm3 was correlated with the low viral load(P < 0.05). 85.4% of the 137 samples with undetermined WB results showed viral loads above 5000 copies/m L. The combined results of undetermined WB and viral loads above 5000 copies/m L were used as diagnostic criteria for HIV infection, which had a diagnostic sensitivity of 85.4%. It would increase to 92.7%(P =0.053) or 96.4%(P =0.002) when the threshold of HIV RNA quantitative assay was set to 2000 copies/m L or 1 000 copies/m L, respectively. Conclusion Low viral loads are relatively common in the natural progression of HIV infection, but accounts for a relatively low proportion at the early stage. Reducing the diagnostic standard of HIV RNA quantitative assay can further increase the rate of early diagnosis of HIV infection.