Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Pernambuco, Brazil.
Centro Universitário Tabosa de Almeida, Caruaru, Pernambuco, Brazil.
PLoS One. 2021 May 17;16(5):e0251861. doi: 10.1371/journal.pone.0251861. eCollection 2021.
Visceral Leishmaniasis and HIV-AIDS coinfection (VL/HIV) is considered a life-threatening pathology when undiagnosed and untreated, due to the immunosuppression caused by both diseases. Serological tests largely used for the VL diagnosis include the direct agglutination test (DAT), ELISA and immunochromatographic (ICT) assays. For VL diagnosis in HIV infections, different studies have shown that the use of the DAT assay facilitates the VL diagnosis in co-infected patients, since the performance of the most widely used ELISA and ICT tests, based on the recombinant protein rK39, are much less efficient in HIV co-infections. In this scenario, alternative recombinant antigens may help the development of new serological diagnostic methods which may improve the VL diagnosis for the co-infection cases. This work aimed to evaluate the use of the recombinant Lci2 antigen, related to, but antigenically more diverse than rK39, for VL diagnosis in co-infected sera through ELISA assays. A direct comparison between recombinant Lci2 and rK39 was thus carried out. The two proteins were first tested using indirect ELISA with sera from VL afflicted individuals and healthy controls, with similar performances. They were then tested with two different sets of VL/HIV co-infected cases and a significant drop in performance, for one of these groups, was observed for rK39 (32% sensitivity), but not for Lci2 (98% sensitivity). In fact, an almost perfect agreement (Kappa: 0.93) between the Lci2 ELISA and DAT was observed for the coinfected VL/HIV patients. Lci2 then has the potential to be used as a new tool for the VL diagnosis of VL/HIV co-infections.
内脏利什曼病和人类免疫缺陷病毒艾滋病合并感染（VL/HIV）如果未经诊断和治疗，由于这两种疾病引起的免疫抑制，被认为是一种危及生命的病理。用于 VL 诊断的血清学检测方法主要包括直接凝集试验（DAT）、ELISA 和免疫层析（ICT）检测。对于 HIV 感染中的 VL 诊断，不同的研究表明，DAT 检测方法的使用有助于合并感染患者的 VL 诊断，因为最广泛使用的 ELISA 和 ICT 检测方法（基于重组蛋白 rK39）在 HIV 合并感染中的性能要低得多。在这种情况下，替代重组抗原可能有助于开发新的血清学诊断方法，从而改善合并感染病例的 VL 诊断。本研究旨在通过 ELISA 检测评估与 rK39 相关但抗原性更广泛的重组 Lci2 抗原在合并感染血清中用于 VL 诊断的用途。因此，对重组 Lci2 和 rK39 进行了直接比较。首先使用间接 ELISA 检测了来自 VL 患者和健康对照者的血清，两种蛋白的检测结果相似。然后用两组不同的 VL/HIV 合并感染病例进行了检测，结果发现 rK39 的检测性能显著下降（敏感性为 32%），但 Lci2 没有（敏感性为 98%）。事实上，对于合并感染的 VL/HIV 患者，Lci2 ELISA 与 DAT 之间观察到几乎完美的一致性（Kappa：0.93）。因此，Lci2 有可能成为 VL/HIV 合并感染 VL 诊断的新工具。
