The microbiome–immunity axis in lung transplantation: Ecological insights and clinical implications

Abstract

Lung transplantation (LTx) is the definitive therapeutic option for patients with end-stage lung disease. Improving long-term survival remains a central focus of clinical research in LTx, particularly because post-transplant infection, acute and chronic rejection, and chronic lung allograft dysfunction continue to limit graft survival. However, the prognosis of LTx recipients depends not only on surgical technique but also on pulmonary microbial ecology and immunosuppressive strategies. In recent years, advances in LTx research have increased interest in the post‑LTx pulmonary microbial ecosystem, especially its dynamic remodeling and multifaceted interactions with the host immune system, which play critical roles in infection, rejection, and long-term prognosis. Previous studies have shown that LTx-induced changes in microbial community structure affect the stability of the pulmonary environment and are closely associated with immune rejection, thereby representing key determinants of graft survival. Mechanistically, microbial dysbiosis may influence innate immune activation, macrophage polarization, regulatory T cells and T helper 17 cells balance, microbial metabolites, and gut–lung axis-mediated systemic inflammation. However, the underlying mechanisms of microbial ecology and immune regulation remain unclear, hindering the development of precision therapies and personalized management strategies. This review summarizes post‑LTx pulmonary microbial community dynamics, immune responses, and bidirectional regulatory mechanisms between the immune system and microbiota, and discusses their impact on graft function, with implications for immune management and microbial ecological regulation strategies. Recent advances in multi-omics analysis, microbiome-related biomarkers, artificial intelligence-assisted analysis, non-invasive monitoring, and methodological standardization may further support precision management in LTx recipients.

Keywords

Lung transplantation / Microbial ecology / Immune mechanisms / Graft rejection / Pulmonary microbiome / Immune regulation

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