Transmitted Drug Resistance and Co-Receptor Tropism of Circulating HIV-1 Subtypes in Art-Naïve HIV Patients in Ghana

Abstract

Combination Anti-retroviral therapy (ART) has significantly reduced the burden of human immunodeficiency virus (HIV-1) infection, transforming it from a fatal disease into a manageable chronic one. The clinical benefits of ART are sustained viral suppression increase in CD4 T lymphocyte counts and improved general well-being. However, the emergence of drug resistance poses a strong challenge to the success of ART in managing HIV infection. Drug resistance (DR) to anti-retrovirals (ARVs) is caused by the high replication capacity of HIV, its error-prone reverse transcriptase and poor compliance by HIV-infected people on ART. In Ghana, reverse transcriptase (RT) and protease inhibitors (PIs) are the main drug combinations. While the transmission of multi-drug resistant variants, determined by genotypic tests, among other HIV-endemic populations informs the choice of drugs in their regimen, clinical management of HIV-1 in Ghana does not include genotypic tests. In this research, we hypothesized that transmitted drug resistant mutants present in treatment-naïve individuals are related to the co-receptors used for cell entry and may hasten ART failure. Sixty-nine treatment-naive HIV-1 infected persons were enrolled from three hospitals in Accra and their clinical histories were obtained. CD4 lymphocytes and HIV-1 viral load were determined for all samples. HIV-1 RNA was extracted from patients’ plasma and HIV Pol region was amplified by conventional PCR and sequenced. The assembled, edited and aligned contigs were used to phylogenetically characterise circulating HIV-1 subtypes. The sequences were submitted to the Stanford University HIV-DR database for analysis of drug resistance mutants. HIV co-receptor preference was measured using TZM-bl indicator cells. The dominant HIV-1 subtype was CRF02_AG (64%), followed by subtype B (26%,) and others, CRF06_cpx, A, C and G, in smaller proportions. This confirms previous reports of CRF)2_AG as predominant subtype and indicates a growing population of the subtype B, which drives the HIV epidemic in Europe and America, in Ghana. Seven mutations on the WHO drug surveillance list were present in nine out of sixty-nine participants enrolled in this study. All seven of them were either non-nucleoside reverse transcriptase (NNRTI) or PI mutations. Quite surprisingly, no nucleoside reverse transcriptase (NRTI) mutations were found. The K103N, which strongly reduces susceptibility to nevirapine and efavirenz was detected in one individual. All PI mutations that were detected were accessory mutations. This was expected since protease inhibitors are not used on a large scale in Ghana. No one individual carried more than one mutation; indicating low levels of transmitted DR among the study population The study participants had mean viral load and CD4 counts of 137,694copies/ml and 409cells/μl respectively and presented no symptoms of disease. Such attributes are indicative of rapid viral replication which is a major driver of drug resistance. Preliminary analysis of the results from the phenotypic assays showed no association between co-receptor phenotypes and identified drug resistance mutations in individuals who carried these mutations. More experiments are needed to confirm these preliminary results. This study has confirmed the predominance of HIV-1 subtype CRF02_AG as the predominant subtype in Ghana while documenting an increase in the circulation of Subtype B. Transmitted HIV drug resistance is still low in Ghana, and this is good for the country’s HIV control programmes. However, continuous surveillance for drug resistance strains among treatment-naïve HIV persons is highly recommended to inform treatment regimens going forward.