Allogeneic B10.BR hearts or syngeneic B6 RAG−/− hearts were transplanted to B6 RAG−/− mice (n=7 and 6, respectively). Grafts were harvested 72 – 82 days later and stained with H&E, MT, and VVG. Syngeneic (left panel) and allogeneic (right panel) grafts appeared identical upon microscopic examination. There was no appreciable inflammatory infiltrate, myocyte dropout, or obliterative arteriopathy in either graft type. Representative whole heart sections stained with H&E are shown.