IBA-1+CD68+ Germinal Center Macrophages Harbor Proviral and Inducible Clade C HIV Reservoirs in ART-Suppressed Human Lymph Nodes

Abstract Despite durable viral suppression, cellular sources of human immunodeficiency virus type 1 (HIV-1) persistence in human lymphoid tissues remain uncharacterized, with germinal center (GC) macrophages representing an understudied, potentially noteworthy reservoir population. Using integrated spatial, phenotypic, and molecular profiling of 42 excisional lymph nodes (LNs) from 39 individuals living with HIV-1 Clade C, including 25 under suppressive antiretroviral therapy (ART), we reveal that GC macrophages harbor HIV-1 DNA, RNA, and proteins, defining them as a functional HIV reservoir. Super-plex imaging confirms HIV co-localization with GC macrophages, which were predominantly IBA-1+CD68+and CD206-CD163-. Among individuals with sustained viral suppression, the presence of proviral DNA (3/6) and inducible multiply spliced HIV-1 RNA (3/3) confirms that LN-resident myeloid cells serve as inducible HIV-1 reservoirs. These reservoirs were markedly enriched in the LNs, with both CD4⁺ and myeloid compartments showing higher inducible activity than their peripheral blood counterparts. While CD4⁺ T cells remain the predominant source of inducible, replication-competent HIV, our detection of a LN myeloid reservoir underscores the imperative to redesign cure approaches to eliminate reservoirs across both CD4⁺ T cell and myeloid lineages.