[1] Univ Manchester, Manchester, Lancs, England
[2] Weill Cornell Med, New York, NY USA
[3] Imperial Coll, Hammersmith Hosp, London, England
[4] Bleeding & Clotting Disorders Inst, Peoria, IL USA
[5] Hosp Sick Children, Toronto, ON, Canada
[6] Texas Childrens Hematol Ctr, Houston, TX USA
[7] Fed Res Ctr Pediat Hematol Oncol & Immunol, Moscow, Russia
[8] Amgen Ltd, Uxbridge, Middx, England
[9] Amgen Inc, Thousand Oaks, CA 91320 USA