Long-term follow-up in composite tissue allotransplantation: in-depth study of five (hand and face) recipients

Composite tissue allotransplantations (CTAs) have clinically shown little, if any, evidence of chronic rejection. Consequently, the effect of chronic rejection on bones, joints, nerves, muscles, tendons and vessels may still have undescribed implications. We thoroughly assessed all allograft structures by histology, magnetic resonance imaging, ultrasonography and high resolution peripheral quantitative computed tomography scan in four bilateral hand-grafted patients (10, 7, 3 and 2 years of follow-up, respectively) and in one facial allotransplantation (5 years of follow-up). All the recipients presented normal skin structure without dermal fibrosis. Vessels were patent, without thrombosis, stenosis or intimal hyperplasia. Tendons and nerves were also normal; muscles showed some changes, such as a variable degree of muscular hypotrophy, particularly of intrinsic muscles, accompanied by fatty degeneration that might be related to denervation. In the majority of hand-grafted patients graft radius and recipient tibia showed a decrease in trabecular density, although in the graft radius the alterations also involved the cortices. No deterioration of graft function was noted. In these cases of CTA no signs of chronic graft rejection have been detected. However, the possibility that chronic rejection may develop in CTA exists, highlighting the necessity of close continuous follow-up of the patients.