Total, Episomal, and Integrated HIV DNA Quantification from HIV Elite Controllers: Insights for Ongoing Replication and HIV Reservoir
Caroline Passaes*1, F Cortes1, G Bello1, D Babic2, M Sharkey2, C Vorsatz3, B Grinsztejn3, V Veloso3, M Stevenson2, and M Morgado1
1Inst Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil; 2Univ of Miami Miller Sch of Med, FL, US; and 3Inst de Pesquisa Clin Evandro Chagas, Fiocruz, Rio de Janeiro, Brazil
Background: Elite controllers (EC) are a rare group of infected patients that can naturally control HIV replication. In spite of that, some of these patients have evidence of viral evolution suggesting that ongoing replication may occur. To assess whether de novo infection is taking place and to verify if residual replication can affect HIV reservoirs in these patients, we performed a cross-sectional analysis of total, episomal, and integrated DNA in a cohort of EC from Rio de Janeiro, Brazil.
Methods: Eleven HIV+ individuals, classified as EC based on the undetectable viremia observed during clinical follow up at IPEC/FIOCRUZ, were recruited for this study. Control groups included: viremic long-term non-progressors (LTNP) patients (n = 8), treatment-naïve viremic patients with high viral loads (n = 26), and patients under suppressive HAART (n = 17). Blood samples were drawn for CD4+ and CD8+ T cell counts, viral load measurements and peripheral blood mononuclear cells were purified for molecular analyses. The study was approved by the institutional review board. Total, episomal, and integrated HIV DNA were quantified by real-time PCR and the Kruskal-Wallis test was used to analyze data.
Results: The 2-LTR circles were detected in 2 out of 11 EC patients (18%), however, despite control of virus replication without therapy in these patients, occasional transient viremia was detected. Episomal DNA was not detected in the remaining patients that completely suppress viremia to levels below the limit of detection of current used assays. The proportion of patients with detectable 2-LTR circles in the EC group, however, was much lower than that of LTNP (7 out of 8 patients; 88%, p = 0.006), treatment naive (24 out of 26 patients; 92%, p = 0.006) and HAART (17 out of 17 patients; 100%, p = 0.007) groups. Total and integrated HIV DNA for the EC group was significantly lower in comparison to both the viremic (p < 0.001) and HAART (p < 0.01) groups.
Conclusions: These results show that natural suppression of HIV replication in EC reduces viremia and episomal DNA to undetectable levels and, as consequence, the residual HIV reservoir is smaller in EC than that seen in successfully HAART treated patients. Two EC patients, however, showed detectable levels of 2-LTR circles, thus demonstrating that de novo infection can occur in these patients. Of note, these 2 EC patients display occasional RNA blips that may lead to generation of the 2-LTR circles detected in those patients.