1. From the Department of Hematology, City Hospital, Nottingham, United Kingdom; Department of Hematology, University Hospital, Birmingham, United Kingdom; Department of Hematology, Royal Free Hospital, London, United Kingdom; Department of Hematology, Kings College Hospital, London, United Kingdom; Department of Hematology, Glasgow Royal Infirmary, Glasgow, United Kingdom; and Department of Hematology, Manchester Royal Infirmary, Manchester, United Kingdom.