1. Department of Pediatric Nephrology and Transplantation, New Children’s Hospital, Pediatric Research Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
2. Department of Pediatric Cardiology, New Children’s Hospital, Pediatric Research Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.
3. Finnish Red Cross Blood Service, Histocompatibility Laboratory, Helsinki, Finland.
4. Division of Cardiology, Department of Pediatrics, Stanford School of Medicine, Helsinki, Finland.