Acute rejection in vascularized composite allotransplantation

Abstract

Acute 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 rejection episodes and highlights recent findings with the potential to improve patient care and enhance understanding of the underlying biologic processes. Recent reports suggest that maintenance immunosuppression dose reduction and steroid withdrawal are realistic goals in VCA, despite the known high immunogenicity of the skin component. It appears that utilization of sentinel flaps, in-depth histological analyses and application of novel biomarkers have facilitated early diagnosis and characterization of acute rejection episodes, leading to timely institution of appropriate therapy. The successful management of the first highly sensitized face transplant recipient suggests the possibility of carefully considering these high-risk VCA candidates for transplantation. Acute rejection is higher in VCA than in any other organ in the field of transplantation, although most episodes are controlled by high-dose steroids and optimization of maintenance immunosuppression. Because of limitations in patient number and the duration of follow-up, the long-term safety and effectiveness of VCA remain unclear. Moreover, the tests currently used to diagnose acute rejection are of limited value. Better diagnostic tools and a better understanding of the immunologic events during acute rejection are therefore needed to improve diagnosis, treatment and outcomes of this life-changing restorative surgery.