Pathological score for the evaluation of allograft rejection in human hand (composite tissue) allotransplantation.

The experience obtained from the human hand allografts (HHA) performed to date suggests that the skin is a priviledged target of allograft rejection in this setting. The aim of this study was to establish a pathological score for assessing the severity of HHA rejection. The pathological slides of 89 skin biopsies obtained from the allografted limbs of six HHA recipients from day 0 to 5 years post-graft were retrospectively examined. According to the severity of the pathological changes observed, the following grades of rejection are proposed: 0: no rejection, I: mild rejection, II: moderate rejection, III: severe rejection, IV: very severe rejection. This grading system can be used as a basis for monitoring allograft rejection and for assessing the effects of the immunosuppressive treatment aiming at reversing HHA rejection; it can also be used for monitoring rejection of other skin-containing CTA.