Seroreactivity clarification and viral load quantitation in HIV-1 and HIV-2 infections in Ghana

Abstract

In Ghana, West Africa, the prevalence of dual HIV-1 and HIV-2 infections remains to be clarified, and HIV viral load measurement is yet to be established. Conventional assays for HIV-1 RNA measurements have been limited specifically to HIV-1 subtype B, preventing their utilization for Ghana where HIV-1 subtypes A, D and G are prevalent. Therefore, we set out to distinguish the types of HIV infection existing in Ghana so as to determine the extent of actual dual infections, and to measure plasma HIV-1 RNA. Blood samples were collected from 563 sick and healthy Ghanaians who visited hospitals in 1996 and 1997. After T cells were counted, HIV antibody was screened and confirmed by six different commercial assays and one in-house test. Nested PCR was then used to verify HIV-1 and HIV-2 presence by type-specific primers. Plasma HIV-1 RNA was measured by an improved commercial RT-PCR assay, sensitive to all HIV-1 group M subtypes. HIV-1 alone (89%) clearly dominated over HIV-2 alone (2%), and HIV-1 and HIV-2 dual infections were found in 9%. Valid viral load measurements were obtained on test plasma representing the main HIV-1 subtype (A) prevailing in Ghana. A high amount of HIV-1 RNA (5.9 mean log10 RNA copies/ml) was observed in the typical stages of HIV infection represented by groups of CD44 cell counts. We have clarified the seroprevalence of HIV-1 and HIV-2 amongst HIV seropositives, and the high viral load of HIV-1 reflects its influence on AIDS in Ghana.