[1] Univ Hamburg, Hosp Eppendorf, Bone Marrow Transplantat Ctr, D-20251 Hamburg, Germany
[2] Univ Hamburg, Hosp Eppendorf, Inst Med Biometry & Epidemiol, D-20251 Hamburg, Germany
[3] Hannover Med Sch, Dept Hematol & Oncol, D-3000 Hannover, Germany
[4] Cincinnati Childrens Res Fdn, Div Expt Hematol, Cincinnati, OH USA