Experiments in mice showed that 1 out of 10 mice that received CD4+ cells from patient A developed very low level HIV viremia (201 copies/mL). Three out of 8 mice that received CD4+ cells from Patient B developed HIV viremia (1,000, 5,000 and 11,000 copies/mL).
Researchers hypothesized that if a true “curative window” of opportunity exists, it may be very small. For example, research suggests that infection can be prevented in monkeys that start ART within 2 days of receiving SIV infection; monkeys started 3 days after receiving SIV experience viral rebound after discontinuing ART, according to studies quoted in the article.
“[A]lthough HIV persisted indefinitely in both of these PrEP cases, a continuum may exist across PrEP, post-exposure prophylaxis and curative early ART strategies. Further investigation in larger cohorts of individuals treated extremely early following HIV infection is warranted,” they concluded.
Due to the rarity of individuals who present with very early HIV infection, the sample size was very small, which may limit the study.
Take Home Points
• Case study of 2 patients found that starting ART at the earliest stage of acute HIV infection is not enough to prevent formation of latent viral reservoirs and prevent HIV rebound upon treatment discontinuation.
• Viremia was fully suppressed for 2 years in Patient A but rebounded after 7.4 months of treatment discontinuation.
• Low-levels of HIV RNA or DNA were intermittently found in Patient B’s blood and CD4+ Tcells, and he did not undergo treatment interruption.
• Mathematical modeling suggested that the latent reservoir size in Patient A was about 200 cells before treatment interruption; about 1% of people with a similar HIV burden might be able to achieve lifelong ART-free remission.
• Further, larger studies are needed to investigate whether a “curative window” exists during which extremely early ART initiation may prevent lifelong infection.
1. Henrich TJ, Hatano H, Bacon O, et al. HIV-1 persistence following extremely early initiation of antiretroviral therapy (ART) during acute HIV-1 infection: an observational study. PLoS Med. 2017 Nov 7;14(11):e1002417.