[1] Univ Coll London Hosp NHS Fdn Trust, Dept Haematol, London, England
[2] UCL Med Sch, London NW3 2PF, England
[3] British Soc Blood & Marrow Transplantat, London, England
[4] Royal Free London NHS Fdn Trust, Dept Haematol, London, England
[5] Univ Coll London Hosp NHS Fdn Trust, Dept Intens Care Med, London, England
[6] Royal Free London NHS Fdn Trust, Dept Immunol, London, England