16,17 ✉ and The International AIDS Society (IAS) Global Scientific Strategy working group*Despite the success of antiretroviral therapy (ART) for people living with HIV, lifelong treatment is required and there is no cure. HIV can integrate in the host genome and persist for the life span of the infected cell. These latently infected cells are not recognized as foreign because they are largely transcriptionally silent, but contain replication-competent virus that drives resurgence of the infection once ART is stopped. With a combination of immune activators, neutralizing antibodies, and therapeutic vaccines, some nonhuman primate models have been cured, providing optimism for these approaches now being evaluated in human clinical trials. In vivo delivery of gene-editing tools to either target the virus, boost immunity or protect cells from infection, also holds promise for future HIV cure strategies. In this Review, we discuss advances related to HIV cure in the last 5 years, highlight remaining knowledge gaps and identify priority areas for research for the next 5 years.

BackgroundAntiretroviral therapy (ART) partially corrects immune dysfunction associated with HIV infection. The levels of T-cell immune activation and exhaustion after long-term, suppressive ART and their correlation with CD4 T-cell count reconstitution among ART-treated patients in African cohorts have not been extensively evaluated.MethodsT-cell activation (CD38+HLA-DR+) and immune exhaustion (PD-1+) were measured in a prospective cohort of patients initiated on ART; 128 patient samples were evaluated and subcategorized by CD4 reconstitution after long-term suppressive treatment: Suboptimal [median CD4 count increase 129 (-43-199) cells/μl], N = 34 ], optimal [282 (200-415) cells/μl, N = 64] and super-optimal [528 (416-878) cells/μl, N = 30].ResultsBoth CD4+ and CD8 T-cell activation was significantly higher among suboptimal CD4 T-cell responders compared to super-optimal responders. In a multivariate model, CD4+CD38+HLADR+ T-cells were associated with suboptimal CD4 reconstitution [AOR, 5.7 (95% CI, 1.4-23, P = 0.014)]. T-cell exhaustion (CD4+PD1+ and CD8+PD1+) was higher among suboptimal relative to optimal (P < 0.001) and super-optimal responders (P < 0.001). T-cell exhaustion was significantly associated with suboptimal responders [AOR, 1.5 (95%CI, 1.1-2.1), P = 0.022].ConclusionT-cell activation and exhaustion persist among HIV-infected patients despite long-term, sustained HIV-RNA viral suppression. These immune abnormalities were associated with suboptimal CD4 reconstitution and their regulation may modify immune recovery among suboptimal responders to ART.

HIV infection causes upregulation of markers of inflammation, immune activation and apoptosis of host adaptive, and innate immune cells particularly monocytes, natural killer (NK) and innate lymphoid cells (ILCs). Although antiretroviral therapy (ART) restores CD4 T-cell counts, the persistent aberrant activation of monocytes, NK and ILCs observed likely contributes to the incomplete recovery of T-cell effector functions. A better understanding of the effects of HIV infection and ART on the phenotype and function of circulating monocytes, NK, and ILCs is required to guide development of novel therapeutic interventions to optimize immune recovery.

Background We examined NK cell phenotypes and functions after seven years of ART and undetectable viral loads (<50 copies/ml) with restored CD4 T-cell counts (≥500 cells/μl) and age-matched healthy-HIV-uninfected individuals from the same community. Methods Using flow-cytometry, NK cell phenotypes were described using lineage markers (CD56 +/- CD16 +/− ). NK cell activation was determined by expression of activation receptors (NKG2D, NKp44 and NKp46) and activation marker CD69. NK cell function was determined by CD107a, granzyme-b, and IFN-gamma production. Results CD56 dim and CD56 bright NK cells were lower among ART-treated-HIV-infected than among age-matched-HIV-negative individuals; p = 0.0016 and p = 0.05 respectively. Production of CD107a (P = 0.004) and Granzyme-B (P = 0.005) was lower among ART-treated-HIV-infected relative to the healthy-HIV-uninfected individuals. NKG2D and NKp46 were lower, while CD69 expression was higher among ART-treated-HIV-infected than healthy-HIV-uninfected individuals. Conclusion NK cell activation and dysfunction persisted despite seven years of suppressive ART with “normalization” of peripheral CD4 counts.

OBJECTIVE T-cell activation independently predicts mortality, poor immune recovery and non-AIDS illnesses during combination antiretroviral therapy (cART). Atorvastatin showed anti-immune activation effects among HIV-infected cART-naïve individuals. We investigated whether adjunct atorvastatin therapy reduces T-cell activation among cART-treated adults with suboptimal immune recovery. METHODS A randomised double-blind placebo-controlled crossover trial, of atorvastatin 80 mg daily vs. placebo for 12 weeks, was conducted among individuals with CD4 increase <295 cells/μl after seven years of suppressive cART. Change in T-cell activation (CD3 + CD4 + /CD8 + CD38 + HLADR+) and in T-cell exhaustion (CD3 + CD4 + /CD8 + PD1 + ) was measured using flow cytometry. RESULTS Thirty patients were randomised, 15 to each arm. Atorvastatin resulted in a 28% greater reduction in CD4 T-cell activation (60% reduction) than placebo (32% reduction); P = 0.001. Atorvastatin also resulted in a 35% greater reduction in CD8-T-cell activation than placebo (49% vs. 14%, P = 0.0009), CD4 T-cell exhaustion (27% vs. 17% in placebo), P = 0.001 and CD8 T-cell exhaustion (27% vs. 16%), P = 0.004. There was no carry-over/period effect. Expected adverse events were comparable in both groups, and no serious adverse events were reported. CONCLUSION Atorvastatin reduced T-cell immune activation and exhaustion among cART-treated adults in a Ugandan cohort. Atorvastatin adjunct therapy should be explored as a strategy to improve HIV treatment outcomes among people living with HIV in sub-Saharan Africa.