Explaining rare cases of HIV remission – and risk of viral rebound after many years off-ART

Simon Collins, HIV i-Base

On 28 October 2021, a press release from the US National Institute of Health (NIH) reported on a recent publication of two cases of continued HIV suppression with ART. [1]

Such cases are extremely rare, but are sometimes observed in studies looking at strategies to cure HIV.

In this case, the main research paper, published in Nature Medicine, reports at least two different mechanisms. [2]

The first case, where HIV was controlled for more than 3.5 years after stopping ART as part of a research study, was explained by high levels of HIV-specific CD8 T cells. This person restarted suboptimal ART without telling the HIV team.

The second person, also from the same research study, remained off-ART for nearly four years, has lower CD8 cells, but had very strong neutralising antibody responses. In this case, ART needed to be restarted after reinfection with another strain of HIV.

Both cases show the challenges of long-term monitoring after short-term examples of HIV remission, and the vulnerability to viral rebound, even after many years of what appears to be HIV remission.

References

1. US NIH press statement. NIH researchers identify how two people controlled HIV after stopping treatment: different mechanisms suppressed the virus in each person. (28 October 2021).
   https://www.niaid.nih.gov/news-events/nih-researchers-identify-how-two-people-controlled-hiv-after-stopping-treatment
2. Blazkova J et al. Distinct mechanisms of long-term virologic control in two HIV-infected individuals after treatment interruption of antiretroviral therapy. Nature Medicine DOI: 10.1038/s41591-021-01503-6 (2021).
   https://www.nature.com/articles/s41591-021-01503-6