Immunosuppressive modulation after vascularized composite allotransplantation: current practice and future directions

Abstract

Vascularized composite allotransplantation (VCA) has expanded the reconstructive options for patients with devastating tissue loss, yet its dependence on lifelong, non-specific systemic immunosuppression remains a defining constraint. Because current protocols are largely extrapolated from solid organ transplantation, they are not well matched to the immunologic heterogeneity of composite grafts, in which skin, mucosa, vasculature, and other tissues each contribute distinct rejection mechanisms. Although VCA demands multi-specialty collaboration, plastic surgeons remain central throughout the reconstructive process and beyond, and must therefore understand how surgical reconstruction, transplantation, and the immune response interact. This narrative review summarizes conventional induction, maintenance, and rejection-directed immunosuppression in VCA; examines how graft composition shapes immunologic risk across hand, face, uterus, abdominal wall, and laryngeal transplantation; and evaluates emerging immunomodulatory strategies. We conclude that the inherent limitations of conventional systemic immunosuppression necessitate a paradigm shift towards phenotype-guided, regional, and tolerance-inducing strategies, with costimulation blockade, regulatory T-cell therapy, and ex vivo graft engineering representing the most promising avenues for future clinical translation.