1. From the Department of Haematology and Transfusion Medicine, University of Oxford, and National Health Service Blood and Transplant — both in Oxford, United Kingdom (L.E.); and the Department of Pathology and Molecular Medicine, Queen’s University, and Kingston Health Sciences Centre, Kingston, and the Department of Laboratory Medicine and Pathobiology, University of Toronto, and Sunnybrook Research Institute, Toronto — all in Ontario, Canada (J.C.).