1. From the Division of Clinical Immunology, Centre for Allogeneic Stem Cell Transplantation, and the Department of Hematology, Karolinska Institute, Huddinge Hospital, Huddinge, Sweden; the Department of Medicine, Helsinki University Hospital, Helsinki; the Department of Medicine, Turku University Hospital, Turku, Finland; the Department of Medicine, Rigshospitalet, Copenhagen, Denmark; the Department of Medicine, Lund; and the Department of Pediatrics, Östra Hospital, Gothenburg, Sweden.