For the roughly 39 million people living with HIV globally, viral suppression via antiretroviral therapy is no longer the finish line — it is the starting point for a subtler, longer battle. Persistent chronic inflammation, even with undetectable viral loads, drives elevated risks of cardiovascular disease, neurocognitive decline, and metabolic disorders. Understanding exactly which biological mechanisms sustain that inflammation has remained elusive, partly because most studies examine only one cellular reservoir at a time.
This study, drawing on a cohort of 164 virally suppressed individuals, used the intact proviral DNA assay to simultaneously quantify HIV reservoirs across both CD4+ T cells and monocytes, then applied unsupervised clustering to let the data self-organize. Five biologically distinct reservoir phenotypes emerged, each paired with a recognizable immune signature. Critically, the monocyte reservoir — historically understudied — was the primary driver differentiating clusters. The five profiles ranged from systemic inflammatory patterns and leukocyte-vascular activation to T cell activation coupled with neuronal injury markers, enhanced CD8 and NK cell recovery states, and altered monocyte survival and migratory signaling. This phenotypic heterogeneity helps explain why inflammation severity varies so widely among treated individuals with similarly controlled viral loads.
The finding reframes HIV reservoir biology in an important way. Prior research has focused almost exclusively on latent CD4+ T cell reservoirs as the engine of residual immune activation, but monocyte-driven reservoirs have been implicated in end-organ complications including HIV-associated neurocognitive disorders and atherosclerosis. This study's multidimensional clustering approach is methodologically notable, though the cross-sectional design in a single cohort limits causal inference. Longitudinal data will be needed to determine whether reservoir phenotypes are stable over time or responsive to intervention. Nonetheless, the framework is potentially paradigm-shifting for clinical stratification: if reservoir phenotyping can prospectively identify which patients face elevated comorbidity risk, targeted immunomodulatory strategies could be deployed before organ damage accumulates.