Abstract

MAFUYEKA, Rendani T.; WEBBER, Lynne M.; BECKER, Piet  and  MAYAPHI, Simnikiwe H.. HIV-1/2 differentiation in a South African public laboratory. South. Afr. j. HIV med. (Online) [online]. 2021, vol.22, n.1, pp.1-7. ISSN 2078-6751.  http://dx.doi.org/10.4102/sajhivmed.v22i1.1185.

BACKGROUND: The human immunodeficiency virus type-2 (HIV-2) prevalence in South Africa (SA) is unknown, however, sporadic cases have been reported. Human immunodeficiency virus -1 and 2 differentiation is not part of most South African public laboratories' testing algorithm. Human immunodeficiency virus -2 diagnosis using serology assays may be complicated by HIV-1 and HIV-2 antibody cross-reactivity. OBJECTIVES: To determine the proportion of HIV-2 infections in specimens that tested HIV-1/2 positive at a public laboratory in Tshwane. METHOD: A total of 480 specimens that were previously tested with fourth generation ELISA platforms (Modular E170 [Roche, Switzerland] and Architect i2000 [Abbott, Germany]) were randomly selected. Human immunodeficiency virus -1 and 2 antibody differentiation testing was carried out using the Multispot HIV-1/2 rapid assay (Bio-Rad Laboratories, USA). An in-house nested HIV-2 PCR assay targeting the 5′-long terminal repeats (5′-LTR) region was evaluated and used as a confirmatory test RESULTS: The study tested 480 HIV-1/2 seropositive patients and their mean age was 36.7 years (range 3-82 years). Of the 480 patients, 292 (60.8%) were female, 182 (37.9%) were male and 6 (1.3%) were not specified. Human immunodeficiency virus differentiation results were as follows: 466 (97.1%) were positive for only HIV-1 antibodies, 11 (2.3%) [95%CI: (0.98%; 3.74%)] were positive for both HIV-1 and HIV-2 antibodies, 3 (0.6%) were negative for both antibodies and none were positive for only HIV-2 antibodies. Of the 11 specimens with both HIV-1 and HIV-2 antibodies, seven had sufficient volume for confirmatory testing and were all negative on the in-house HIV-2 PCR assay. CONCLUSION: The multispot HIV-1/2 rapid assay demonstrated cross-reactivity between HIV-1 and HIV-2 antibodies. Human immunodeficiency virus -2 infections were not detected.

Keywords : HIV-1/2 differentiation; HIV-2 testing; HIV1/2 antibody cross reaction; HIV-2 in South Africa; HIV-2 PCR.

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