No Difference in the Prevalence of HIV-1 gag Cytotoxic T-Lymphocyte-Associated Escape Mutations in Viral Sequences from Early and Late Parts of the HIV-1 Subtype C Pandemic in Botswana.

HIV is known to accumulate escape mutations in the gag gene in response to the immune response from cytotoxic T lymphocytes (CTLs). These mutations can occur within an individual as well as at a population level. The population of Botswana exhibits a high prevalence of HLA*B57 and HLA*B58, which are associated with effective immune control of HIV. In this retrospective cross-sectional investigation, HIV-1 gag gene sequences were analyzed from recently infected participants across two time periods which were 10 years apart: the early time point (ETP) and late time point (LTP). The prevalence of CTL escape mutations was relatively similar between the two time points-ETP (10.6%) and LTP (9.7%). The P17 protein had the most mutations (9.4%) out of the 36 mutations that were identified. Three mutations (A83T, K18R, Y79H) in P17 and T190A in P24 were unique to the ETP sequences at a prevalence of 2.4%, 4.9%, 7.3%, and 5%, respectively. Mutations unique to the LTP sequences were all in the P24 protein, including T190V (3%), E177D (6%), R264K (3%), G248D (1%), and M228L (11%). Mutation K331R was statistically higher in the ETP (10%) compared to the LTP (1%) sequences (p < 0.01), while H219Q was higher in the LTP (21%) compared to the ETP (5%) (p < 0.01). Phylogenetically, the gag sequences clustered dependently on the time points. We observed a slower adaptation of HIV-1C to CTL immune pressure at a population level in Botswana. These insights into the genetic diversity and sequence clustering of HIV-1C can aid in the design of future vaccine strategies.

Prediction of Coreceptor Tropism in HIV-1 Subtype C in Botswana.

It remains unknown whether the C-C motif chemokine receptor type 5 (CCR5) coreceptor is still the predominant coreceptor used by Human Immunodeficiency Virus-1 (HIV-1) in Botswana, where the HIV-1 subtype C predominates. We sought to determine HIV-1C tropism in Botswana using genotypic tools, taking into account the effect of antiretroviral treatment (ART) and virologic suppression. HIV-1 gp120 V3 loop sequences from 5602 participants were analyzed for viral tropism using three coreceptor use predicting algorithms/tools: Geno2pheno, HIV-1C Web Position-Specific Score Matrices (WebPSSM) and the 11/25 charge rule. We then compared the demographic and clinical characteristics of people living with HIV (PLWH) harboring R5- versus X4-tropic viruses using χ2 and Wilcoxon rank sum tests for categorical and continuous data analysis, respectively. The three tools congruently predicted 64% of viruses as either R5-tropic or X4-tropic. Geno2pheno and the 11/25 charge rule had the highest concordance at 89%. We observed a significant difference in ART status between participants harboring X4- versus R5-tropic viruses. X4-tropic viruses were more frequent among PLWH receiving ART (χ2 test, p = 0.03). CCR5 is the predominant coreceptor used by HIV-1C strains circulating in Botswana, underlining the strong potential for CCR5 inhibitor use, even in PLWH with drug resistance. We suggest that the tools for coreceptor prediction should be used in combination.

Undetectable proviral deoxyribonucleic acid in an adolescent perinatally infected with human immunodeficiency virus-1C and on long-term antiretroviral therapy resulted in viral rebound following antiretroviral therapy termination: A case report with implications for clinical care.

RATIONALE: Early initiation of antiretroviral therapy (ART) leads to long-term viral suppression, reduces proviral reservoir size, and prolongs time to rebound. Since human immunodeficiency virus (HIV) is a lifelong disease, diagnostic monitoring after confirmed infection is typically not performed; therefore, little is known about the impact of early initiation and long-term ART on the sensitivity of assays that detect HIV antibodies and viral nucleic acid in children and adolescents. PATIENT CONCERNS: Here we report 1 case of diagnosed and confirmed perinatal HIV-1C infection with longstanding viral suppression, who subsequently had a negative HIV-1 deoxyribonucleic acid (DNA) test, undetectable antibodies to HIV-1, and high CD4+ T cell count after 14 years of ART. DIAGNOSIS: The patient was diagnosed with HIV in 2002 at 1 and 2 months of age using DNA polymerase chain reaction. At 8 months old, his viral load was 1210 HIV ribonucleic acid (RNA) copies/mL and CD4 T cell count was 3768 cells/mm. INTERVENTION: At the age of 9 months, highly active antiretroviral therapy comprising of zidovudine, nevirapine, and lamivudine was initiated. The patient remained on this treatment for 14 years 11 months and was virally suppressed. OUTCOMES: At the age of 14 years 4 months, the participant decided to visit a local voluntary HIV testing center, where a rapid HIV test came out negative and the viral load was undetectable (<400 HIV-1 RNA copies/mL). These results led to termination of ART which led to viral rebound within 9 months. LESSONS: As more people with early HIV infection initiate early ART in the context of "Test and Treat all" recommendations, aspects of this report may become more commonplace, with both clinical and public health implications. If the possibility of functional cure (or false-positive diagnosis) is being considered, decisions to terminate ART should be made cautiously and with expert guidance, and may benefit from highly sensitive quantification of the proviral reservoir.