RESUMEN
A 9-year-old boy of B blood group with end-stage renal disease due to IgA nephropathy received group O kidney transplantation from his father. On day 9, he developed intravascular hemolysis, and anti-B autoantibody formation was confirmed. We diagnosed as immune hemolytic anemia due to passenger lymphocyte from donor, and cyclosporine withdrawl was done. Anemia resolved spontaneously, but on day 18, graft dysfunction developed, and graft biopsy revealed acute allograft rejection. Although hemolysis due to autoantibody is very rare and often mild, and the role of hemoglobinuria on acute rejection in this case is not certain, we recommend consideration of aggressive management on severe hemolysis after minor mismatched kidney transplantation.