Extracellular Vesicles and Immune Activation in Solid Organ Transplantation: The Impact of Immunosuppression.

Recent advances in extracellular vesicle (EV) research in organ transplantation have highlighted the crucial role of donor-derived EVs in triggering alloimmune responses, ultimately contributing to transplant rejection. Following transplantation, EVs carrying donor major histocompatibility complex (MHC) molecules activate recipient antigen-presenting cells (APCs), initiating both alloreactive and regulatory T-cell responses. While immunosuppressive drugs are essential for preventing rejection, they may also influence the biogenesis and release of EVs from donor cells. This review examines the impact of maintenance immunosuppressive therapy on EV biogenesis and release post-transplantation. In addition, EV release and uptake may be influenced by specific factors such as the patient's end-stage organ disease and the transplant procedure itself. In-vitro studies using primary human parenchymal and immune cells-integrated with cutting-edge multi-omics techniques, including genomics, proteomics, lipidomics, and single-EV analysis-will offer deeper insights into EV biology and the mechanisms by which immunosuppressive agents regulate EV-initiated immune processes. A detailed understanding of how organ failure, the transplantation procedure and immunosuppressive drugs affect the biology of EVs may uncover new roles for EVs in immune activation and regulation in patients, ultimately leading to improved immunosuppressive strategies and better transplant outcomes.