HIV抗体免疫印迹试验不确定结果的特征及鉴别方法研究

Study on the indeterminate results of characterization and verification of HIV antibody from Western blot test

目的研究HIV抗体确认不确定结果的血清学特征并比较不同实验方法鉴别不确定结果的效果。方法以解放军艾滋病检测确认实验室2005—2006年确认的42例HIV抗体不确定者为研究对象，对血清样本进行HIV抗体条带免疫印迹检测、HIV病毒载量检测和HIV-1 p24抗原检测，同时进行随访，将随访前后的标本同时检测，比较免疫印迹带型的进展，判断HIV感染的真实状况，以随访的结果为标准，判断不同的方法鉴别不确定结果的效果。结果（1）42例HIV抗体不确定病例中，共有8种带型：p24（45．2％）、gp160（30．9％）、gp160±p24（11．9％）。（2）对23例进行3个月以上随访，其中22例带型没有变化，判断为HIV抗体阴性；1例的带型在随访后出现显著进展，满足HIV抗体阳性诊断标准；随访证实，22例（95．6％）的不确定是非特异反应，只有1例是早期HIV感染。（3）对23例通过随访确定HIV感染状态的病例，条带免疫印迹检测1例血清学阳转的病例为阳性，22例血清学没有进展的病例巾16例为阴性，6例仍为不确定，特异性是72．7％。HIV-1 p24抗原检测23份标本全部为阴性，1例血清学阳转标本漏检。检测7份血浆标本的病毒载量，1例血清学阳转的病例病毒载量为18000cp／ml，而6例血清学没有进展的病例检测结果全部低于最低检测限（〈LDL）。结论条带免疫印迹试验能够鉴别大约70．0％的不确定反应，病毒载量检测也是鉴别不确定结果的有效方法；使用这两种方法，可以对HIV抗体不确定进行早期鉴别诊断。

Objective To study the serological characterization of indeterminate Western blot （WB） results of HIV antibody and to find a new way to verify the HIV antibody indeterminate results and provide references for editing ＂National Guideline for Detection of HIV/AIDS＂. Methods All of the 42 subjects who were confirmed as indeterminate HIV antibody in People＇ Libaretion Amry HIV Confirmation Laboratory from 2005 to 2006, were collected. Line immunoassay, HIV viral load test and HIV-1 p24 were tested and followed up for 3-6 months＇ to compare the changes of WB bands patterns. Results （ 1 ） For the 42 individuals with indeterminate HIV antibody, a total of 8 different patterns of bands were found in WB test including 45.2% of them were p24 monoband, 30.9% were gp160 monoband, 11.9% were gp160 with p24, 2.4% （only one case） were gp160gp120 ±, gp41p24, p24p17, gp41 or gp120 respectively. It was noticed that the most patterns of common bands with indeterminate results were p24 monoband, gp160 monoband and gp160 with p24, which composed 88.0 % of the whole indeterminate WB band patterns. （2） Twenty three cases had been followed up for more than 3 months with 22 giving no WB band image change and were confirmed as HIV sero-negative. The other one with case gp160 and p24 had developed to more bands in the period of 77 days follow-up with more bands, including gp160, gp120, p66, p31, p24 and pl7,showed up and was confirmed as HIV primary infection. （3） Line immunoassay was applied to all of those 23 cases who bad been followed up and the results showed that only one serological change was found and the case was confirmed to be HIV-positive. Among the other 22 cases without serological changes, 16 cases were proved to be HIV-negative, 6 cases were still indeterminate. The specificity was 72.7 %. P24 antigen test showed negative in all the 23 cases, including the case which later was confirmed as HIV-positive. Of all the 23 originally indeterminate cases, viral loads were tested in 7 cases. Positive result was found in the case which was proved later to be HIV-positive. No viral loads were detected in the other 6 cases （〈 LDL）. Conclusion The most common band patterns of indeterminate HIV antibody were mainly p24 monoband, gp160 monoband or with p24. Most of them （95.6%） were not infected by HIV, the bands showed up in WB test and demonstrated as non-specific reactions. Line immunoassay could determine about 70 % of the indeterminate reactions. Results from viral load test also suggested that it was an efficient method to discriminate indeterminate results. With these two techniques, HIV serology could be diagnosed without 3 months＇ follow-up in primary infection which gave indeterminate WB results.