Virologically suppressed people with HIV infection on antiretroviral therapy (ART) may still harbor the latent virus in the myeloid cells (monocytes and macrophages), suggests a NIH study published in the journal Nature Microbiology.¹

In this study, Veenhuis et al selected 30 virologically suppressed people with HIV infection on antiretroviral therapy (ART) for a minimum of 5 years. Latent virus was detected in the monocytes and macrophages with a myeloid-adapted intact proviral DNA assay (IPDA), even though the virus levels were significantly lower than the levels in the CD4 cells. Forty percent of the subjects were found to have intact genomes in monocyte-derived macrophages indicating that the virus could infect other cells upon reactivation. They also had higher total HIV DNA. Using the human monocyte-derived macrophage quantitative viral outgrowth assay (MDM-QVOA), the researchers sought to look for latent HIV in monocytes in 10 virally suppressed men with HIV. Half of them showed latent HIV in monocytes. Some participants were still found to have these virus reservoirs over a follow up of several years.

This study has attempted to quantify the latent virus in virally suppressed people using the QVOA and IPDA techniques. Nearly half of them had the latent virus in monocyte-derived macrophages, which was capable of being reactivated leading to viral rebound if ART is stopped. The CD4 cell (T lymphocytes or helper T cells) count is usually monitored to assess disease progression or suppression. Rather than focusing solely on CD4 cells, myeloid cells must also be monitored since they are reservoirs of HIV as shown in this study.

Reference

1. Veenhuis RT, et al. Monocyte-derived macrophages contain persistent latent HIV reservoirs. Nat Microbiol. 2023 Mar 27. doi: 10.1038/s41564-023-01349-3.