The Gut Microbiome in HIV Pathogenesis: Interconnections Between Dysbiosis, Immune Dysfunction, and Viral Persistence

The human gut microbiome is essential for immune regulation and mucosal homeostasis, functions that are profoundly disrupted during HIV infection. Early viral replication in the gut-associated lymphoid tissue (GALT) triggers a self-reinforcing cycle of CD4+ T-cell depletion, epithelial barrier breakdown, and increased microbial translocation. This persistent immune activation continues even under effective antiretroviral therapy (ART). A growing body of evidence indicates that HIV infection is consistently associated with alterations in gut microbial communities. This dysbiosis is typically characterized by fewer beneficial butyrate-producing commensal bacteria and an enrichment of pro-inflammatory microbial taxa. It also involves disturbances in key microbial metabolites, including short-chain fatty acids (SCFAs) and tryptophan catabolites. Such changes not only exacerbate systemic inflammation but may also contribute to incomplete immune reconstitution and the persistence of latent viral reservoirs despite long-term ART. In this review, we summarize current knowledge of microbiome–HIV interactions, with particular emphasis on the mechanisms through which gut dysbiosis contributes to immune dysfunction and viral persistence. We discuss recent advances in multi-omics technologies, as well as experimental systems such as gnotobiotic and humanized mouse models and intestinal organoid platforms that are helping to elucidate these complex interactions. Furthermore, we evaluate emerging microbiome-targeted interventions—including probiotics, prebiotics, fecal microbiota transplantation, and engineered bacterial therapeutics—and consider their potential role as adjunctive strategies in HIV treatment and cure research. By integrating microbiological, immunological, and clinical perspectives, this review highlights key knowledge gaps and outlines future research directions aimed at harnessing the gut microbiome as a novel therapeutic avenue in HIV management and eradication.