Abstract 48: A Clinically Relevant Protocol for Vascularized Composite Allotransplantation Using A Single Dose of AMD3100 for Stem Cell Mobilization

RESULTS: Durable mixed chimerism (only detected transiently at 6 weeks post-DBMT) did not develop but recipients managed to come off all IS for 4–5 weeks before acute rejection (Banff II) developed between POD115-POD126. Rejection could be treated and reversed both clinically and histologically. However, following subsequent re-withdrawal of IS, Banff II rejection developed again within 2 weeks (on POD172), could not be reversed despite treatment (Banff II on POD195) and ultimately culminated in necrosis of the VCA (on POD224). Final histology showed severe acute cellmediated and antibody-mediated rejection with C4d deposition in subcutaneous arteries and arterioles as well as chronic allograft vasculopathy. Despite these findings, corresponding serial MLR assays demonstrate unresponsiveness after DBMT and no allo-antibody formation was detected.