[1] Univ Duisburg Essen, Univ Hosp Essen, Dept Hematol, West German Canc Ctr, Essen, Germany
[2] Univ Hosp Essen, Inst Transfus Med, Essen, Germany
[3] Univ Duisburg Essen, Univ Hosp Essen, West German Canc Ctr, Dept Pediat Oncol Hematol, Essen, Germany
[4] Univ Duisburg Essen, West German Canc Ctr, Dept Bone Marrow Transplantat, Univ Hosp Essen, Essen, Germany