1. From the Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom; Millennium Pharmaceuticals, Cambridge, MA; the Department of Haematology, Heartlands Hospital, Birmingham, United Kingdom; the Department of Haematology, Leeds General Infirmary, United Kingdom; the Department of Hematology, Huddinge Hospital, Sweden; the Department of Haematology, Stobhill Hospital, Glasgow, United Kingdom; and the Departments of Hematology and Oncology, Karolinska Hospital, Stockholm, Sweden.