Re‐testing and misclassification of HIV‐2 and HIV‐1&2 dually reactive patients among the HIV‐2 cohort of The West African Database to evaluate AIDS collaboration

Abstract

Introduction West Africa is characterized by the circulation of HIV‐1 and HIV‐2. The laboratory diagnosis of these two infections as well as the choice of a first‐line antiretroviral therapy (ART) is challenging, considering the limited access to second‐line regimens. This study aimed at confirming the classification of HIV‐2 and HIV‐1&2 dually reactive patients followed up in the HIV‐2 cohort of the West African Database to evaluate AIDS collaboration. Method A cross‐sectional survey was conducted from March to December 2012 in Burkina Faso, Côte d’Ivoire and Mali among patients classified as HIV‐2 or HIV‐1&2 dually reactive according to the national HIV testing algorithms. A 5‐ml blood sample was collected from each patient and tested in a single reference laboratory in Côte d’Ivoire (CeDReS, Abidjan) with two immuno‐enzymatic tests: ImmunoCombII® (HIV‐1&2 ImmunoComb BiSpot – Alere) and an in‐house ELISA test, approved by the French National AIDS and hepatitis Research Agency (ANRS). Results A total of 547 patients were included; 57% of them were initially classified as HIV‐2 and 43% as HIV‐1&2 dually reactive. Half of the patients had CD4≥500 cells/mm3 and 68.6% were on ART. Of the 312 patients initially classified as HIV‐2, 267 (85.7%) were confirmed as HIV‐2 with ImmunoCombII® and in‐house ELISA while 16 (5.1%) and 9 (2.9%) were reclassified as HIV‐1 and HIV‐1&2, respectively (Kappa=0.69; p<0.001). Among the 235 patients initially classified as HIV‐1&2 dually reactive, only 54 (23.0%) were confirmed as dually reactive with ImmunoCombII® and in‐house ELISA, while 103 (43.8%) and 33 (14.0%) were reclassified as HIV‐1 and HIV‐2 mono‐infected, respectively (kappa= 0.70; p<0.001). Overall, 300 samples (54.8%) were concordantly classified as HIV‐2, 63 (11.5%) as HIV‐1&2 dually reactive and 119 (21.8%) as HIV‐1 (kappa=0.79; p<0.001). The two tests gave discordant results for 65 samples (11.9%). Conclusions Patients with HIV‐2 mono‐infection are correctly discriminated by the national algorithms used in West African countries. HIV‐1&2 dually reactive patients should be systematically investigated, with a standardized algorithm using more accurate tests, before initiating ART as at least 4 out of 10 of them could initiate an effective first‐line ART for HIV‐1 and optimize their second‐line treatment options.

Keywords

• HIV‐2
• HIV‐1&2 dually reactive
• testing
• classification
• West Africa