[1] Leeds Childrens Hosp, Leeds, W Yorkshire, England
[2] Univ Leeds, Leeds, W Yorkshire, England
[3] Sheffield Childrens Hosp, Dept Pediat Hematol, Sheffield S10 2TH, S Yorkshire, England
[4] Great Ormond St Hosp Sick Children, Dept Haematol, London WC1N 3JH, England
[5] CTSU, Oxford, England
[6] John Radcliffe Hosp, Oxford OX3 9DU, England
[7] UCL, Inst Canc, London, England
[8] Univ Wales Hosp, Cardiff CF4 4XW, S Glam, Wales