Extracorporeal Photopheresis in Solid Organ Transplantation: Modulating B-cell Responses to Improve Graft Survival

Solid organ transplantation remains the only curative treatment for end-stage organ diseases. A critical aspect of enhancing long-term graft survival is to prevent antibody-mediated rejection caused by donor-specific antibodies (DSAs). DSAs are formed when donor alloantigen-specific B cells differentiate into antibody-secreting cells. In this review, we explore what is known about the relationship between treatment with extracorporeal photopheresis (ECP) and its effects on undesired B-cell activation and DSA formation. Current preliminary evidence suggests that ECP, when used as an adjuvant therapy, displays significant benefits, including allograft survival, decreased circulating DSAs, and downregulated activation of the allogeneic immune response, possibly through expansion of regulatory B cells. Despite these promising findings, the precise mechanisms through which ECP affects B-cell fate remain incompletely understood. Further research into specific B-cell subpopulations is necessary to fully elucidate the role of ECP in modulating pathways involved in DSA formation, which might allow more effective management of antibody-mediated rejection.