Hussain Tahziba, Sinha Shikha, Katoch Kiran, Yadav V S, Kulshreshtha K K, Singh Itu, Sengupta U, Katoch V M
HIV/AIDS UNIT & Clinical Division, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (Indian Council of Medical Research), Tajganj, Agra 282001, India.
Lepr Rev. 2007 Jun;78(2):137-47.
Infection with Mycobacterium leprae is associated with a high frequency of false positive results in a variety of serological assays. Our studies have found cross-reactivity to HIV structural proteins in serum samples from leprosy patients, irrespective of the type of disease, treatment duration, age and gender and from a few patients with active TB disease.
Western blot (WB) analysis revealed that sera from HIV negative leprosy patients across the spectrum showed high reactivity with p18, Gp41 and p55 and lower reactivity with other HIV proteins. The reactivity appeared to be specific; western blot-positive samples were negative in ELISA and in several rapid tests for HIV. Cross-reactivity was not found in sera from patients with leishmaniasis or from normal healthy individuals.
None of the WB reactive leprosy patients seroconverted to HIV positivity within 6 months to 1 year after Western blot testing. BLAST analysis revealed that envelope antigens of HIV (Gp41, Gp120 and Gp160) contained amino acid sequences similar to M. leprae ML0470, putative integral membrane protein, Rv0740, mmpL9 (M. tuberculosis). Core (gag) antigens (p18) had similarities to ML0406, but polymerase antigens (p52) had similarities to PE_PGRS (M. tuberculosis, H37Rv). Nucleotide sequence analysis, on the other hand, did not reveal any significant homology between M. leprae or M. tuberculosis and HIV.
The occurrence of these high false-positive rates in M. leprae-infected individuals suggests a possible complication of serodiagnosis of HIV in regions where mycobacterial infections are endemic. There is a need for caution in reporting HIV infection among leprosy patients. Our observations emphasise the value of the various rapid assay kits for HIV, where this false positivity is not observed.
麻风分枝杆菌感染在多种血清学检测中常出现高频率的假阳性结果。我们的研究发现，麻风病患者的血清样本中存在与HIV结构蛋白的交叉反应，无论疾病类型、治疗时长、年龄和性别如何，少数活动性结核病患者的血清样本中也存在这种情况。
蛋白质印迹（WB）分析显示，不同类型的HIV阴性麻风病患者血清与p18、Gp41和p55具有高反应性，与其他HIV蛋白的反应性较低。这种反应似乎具有特异性；蛋白质印迹阳性样本在ELISA和几种HIV快速检测中均为阴性。利什曼病患者或正常健康个体的血清中未发现交叉反应。
在蛋白质印迹检测后的6个月至1年内，没有WB反应性的麻风病患者血清转化为HIV阳性。BLAST分析显示，HIV的包膜抗原（Gp41、Gp120和Gp160）含有与麻风分枝杆菌假定的整合膜蛋白ML0470、结核分枝杆菌Rv0740、mmpL9相似的氨基酸序列。核心（gag）抗原（p18）与ML0406相似，但聚合酶抗原（p52）与结核分枝杆菌（H37Rv）的PE_PGRS相似。另一方面，核苷酸序列分析未发现麻风分枝杆菌或结核分枝杆菌与HIV之间存在任何显著同源性。
麻风分枝杆菌感染个体中出现这些高假阳性率表明，在分枝杆菌感染流行的地区，HIV血清学诊断可能存在并发症。在报告麻风病患者的HIV感染情况时需要谨慎。我们的观察结果强调了各种HIV快速检测试剂盒的价值，这些试剂盒未观察到这种假阳性情况。
