C URRENT OPINION Acute rejection in vascularized composite allotransplantation

Purpose of reviewAcute rejection is the most common complication after vascularized composite allotransplantation (VCA).This review provides a state-of-the-art analysis of prevention, diagnosis and treatment of acute rejectionepisodes and highlights recent findings with the potential to improve patient care and enhanceunderstanding of the underlying biologic processes.Recent findingsRecent reports suggest that maintenance immunosuppression dose reduction and steroid withdrawal arerealistic goals in VCA, despite the known high immunogenicity of the skin component. It appears thatutilization of sentinel flaps, in-depth histological analyses and application of novel biomarkers havefacilitated early diagnosis and characterization of acute rejection episodes, leading to timely institution ofappropriate therapy. The successful management of the first highly sensitized face transplant recipientsuggests the possibility of carefully considering these high-risk VCA candidates for transplantation.SummaryAcute rejection is higher in VCA than in any other organ in the field of transplantation, although mostepisodes are controlled by high-dose steroids and optimization of maintenance immunosuppression. Becauseof limitations in patient number and the duration of follow-up, the long-term safety and effectiveness of VCAremain unclear. Moreover, the tests currently used to diagnose acute rejection are of limited value. Betterdiagnostic tools and a better understanding of the immunologic events during acute rejection are thereforeneeded to improve diagnosis, treatment and outcomes of this life-changing restorative surgery.Keywordsacute rejection, face transplantation, facial allograft, hand transplantation, vascularized composite tissueallotransplantation