Gut microbiota-associated non-cholesterol sterol dysregulation modulates immune reconstitution during antiretroviral therapy in people living with HIV

Non-cholesterol sterol metabolism plays a crucial role in immune regulation. However, the non-cholesterol sterol profiles, its association with gut dysbiosis, and its impact on the CD4⁺ T cell recovery in people living with HIV (PLWH) are yet to be elucidated. In this study, we recruited 37 PLWH and 50 healthy controls to characterize non-cholesterol sterol profiles and gut microbiota composition using targeted liquid chromatography-mass spectrometry and metagenomic analysis. Correlations between sterol profiles and immune cell subsets were assessed. <i>In vitro</i> peripheral blood mononuclear cell (PBMC) model was used to validate key findings. We identified a distinct dysregulation of non-cholesterol sterol metabolism in PLWH, characterized by elevated levels of cholesterol precursors and metabolites and depleted levels of plant sterols, which were linked to gut dysbiosis. Our study results highlighted <i>Oscillibacter</i> spp. as the key regulator of sterol metabolism. Specifically, plant sterols (e.g., brassicasterol and campesterol) were found to be associated with impaired CD4⁺ T cell recovery during antiretroviral therapy (ART). These findings were validated using <i>ex vivo</i> PBMC models, which revealed that brassicasterol stimulates T cell abnormal activation and pro-inflammatory cytokine release, whereas lathosterol dampens immune activation and inflammation. In summary, our study highlights the interplay between gut dysbiosis and sterol dysregulation in PLWH, demonstrating that higher brassicasterol levels impair immune recovery post-ART by promoting CD4⁺ T cell hyperactivation. Hence, targeting microbial sterol metabolism-through <i>Oscillibacter</i> spp. enrichment or plant sterol modulation-may offer novel therapeutic strategies to optimize ART outcomes by balancing immune activation and resolution.IMPORTANCEThis study is the first to integrate non-cholesterol sterol profiling with gut microbiota analysis in people living with HIV (PLWH), uncovering a unique sterol dysregulation characterized by elevated cholesterol precursors and depleted plant sterols in this population. We demonstrate that <i>Oscillibacter</i> spp. were associated with these metabolic shifts and that specific sterols differentially affect immune recovery: plant sterols such as brassicasterol impede CD4⁺ T cell restoration by promoting hyperactivation, whereas the cholesterol derivative lathosterol mitigates inflammation and supports immune reconstitution. These insights reveal novel microbiome-sterol interactions that can be leveraged to develop targeted microbiome- and sterol-based interventions aimed at enhancing antiretroviral therapy efficacy and long-term immune health in PLWH.