Drug Resistance Mutations in HIV Patients on Antiretroviral Therapy in Ghana

Abstract

Highly active antiretroviral therapy (HAART) is known to improve treatment in Human Immunodeficiency Virus (HIV)-infected patients but the emergence of drug resistance is an obstacle in the effective management of HIV infection and Acquired Immune Deficiency Syndrome (AIDS). Plasma viral load monitoring is the gold standard used in high-income countries for monitoring treatment but it is not available in many resource-limited settings. Although limited viral load testing is now available in Ghana, viral load is not routinely used for monitoring majority of patients on HAART. Physicians in Ghana therefore depend mainly on CD4 counts and clinical symptoms to monitor treatment. Thus, a significant proportion of patients may suffer virologic failure while continuing to take first-line antiretroviral therapy (ART). This may encourage the development and accumulation of drug resistance mutations and compromise future treatment efforts. The aim of this study was to investigate the presence of HIV drug resistance mutations in patients on ART in Ghana, relate these mutations to treatment regimens in order to inform policy on ART monitoring and patient management in the country. Venous blood was obtained from 338 patients on ART from the Korle-Bu Teaching, St. Martin de Porres, Atua Government and Kumasi South hospitals in Ghana. Personal information and ART history of the patients were also collected using a sample collection form. The CD4 counts and viral loads of patients were determined. HIV ribonucleic acid (RNA) and proviral deoxyribonucleic acid (DNA) were extracted from the plasma and peripheral blood mononuclear cells (PBMC), respectively. The HIV protease and reverse transcriptase genes were amplified from the RNA and DNA by polymerase chain reaction. The positive amplification products were sequenced and analyzed for drug resistant mutations using the Stanford HIV Drug Resistance Database. The mean age of patients was 42 years and 72% of patients were female. The mean CD4 counts increased from 161cells/μl at start of therapy to 454cells/μl at time of sampling. Only 7% of patients had detectable viral loads at time of sampling. Most of the patients (87%) were on first-line regimen. Physicians rating showed that 86% of patients were doing well and the rest were either not doing so well (11%) or were failing (3%). The reverse transcriptase gene was successfully sequenced from 65 (19%) and 99 (29%) of plasma and PBMC respectively while protease gene was successfully sequenced from 54 (16%) of plasma and 76 (23%) of PBMC. Out of these, 46 % and 49% of the plasma sequences had nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations respectively. From PBMC, 25% and 26%, respectively had NRTI and NNRTI mutations. Protease inhibitor (PI) resistance mutations were found in 28% of plasma and 9% of PBMC sequences. The most common NRTI mutation found was M184V and that of NNRTI was K103N. Thymidine analogue mutations (TAMs) including M41L, D67N, T215Y/F, L210W and K219E/Q were mostly found in patients on second-line regimen. Protease inhibitor mutations were mainly found in patients on second-line regimen and they included M46I, V82I and N88S. Similar resistance profiles were observed in paired sequences from plasma and PBMC of the same patients. The results showed that even patients who were doing well, based on their CD4 counts, viral load and physicians assessment, were harbouring drug resistance mutations including TAMs that could render the NRTIs ineffective. The results suggest that CD4 count is an insufficient marker for monitoring treatment since it continues to increase even in the presence of drug resistance mutations. Patients on ART in Ghana may therefore not be deriving optimal benefits from treatment because of the current monitoring system. Therefore drug resistance testing will be useful before switching regimens in order to decide drugs in the new regimen. This will reduce the accumulation of multi-nucleoside and thymidine analog mutations in patients and preserve future drug options. The study has provided vital drug resistance data to guide policy on ART monitoring in Ghana, improved protocols for HIV genotyping at the Virology Department of the NMIMR and built capacity for drug resistance analyses of patients that fail ART in Ghana.