This is another example of severe arteriopathy occuring as a result of transplantation across ABO blood group barriers. This section was stained with periodic-acid Schiff(PAS) reagent, which highlights glycogen and glycoproteins. Note the PAS positive material, which is IgM, obliterating the lumena of the hepatic arterial branches in an ABO incompatible allograft that failed 3 days after transplantation.