1. From the University of Cambridge School of Clinical Medicine and the Department of Haematology, Addenbrooke's Hospital, Cambridge, United Kingdom; Chelsea and Westminster Hospital, London, United Kingdom; Medical Research Council Biostatistics Unit, Institute of Public Health, Cambridge, United Kingdom; University of Cambridge Department of Physics, Cavendish Laboratory, United Kingdom; and School of Molecular and Microbial Biosciences, University of Sydney, New South Wales, Australia.