[1] Univ Childrens Hosp, Dept Pediat 1, D-69120 Heidelberg, Germany
[2] Heidelberg Univ, Inst Med Biometry & Informat, Heidelberg, Germany
[3] Heidelberg Univ, Coordinat Ctr Clin Trials, Heidelberg, Germany
[4] Eurotransplant Fdn, Leiden, Netherlands
[5] Hannover Med Sch, Ctr Paediat & Adolescent Med, Hannover, Germany
[6] Univ Childrens Hosp, Essen, Germany
[7] Great Ormond St Hosp Sick Children, London WC1N 3JH, England
[8] Royal Manchester Childrens Hosp, Manchester M27 1HA, Lancs, England
[9] Gazi Univ, Ankara, Turkey
[10] Hacettepe Univ, Ankara, Turkey
[11] Semmelweis Univ, Dept Pediat 1, H-1085 Budapest, Hungary
[12] Charles Univ Prague, Univ Childrens Hosp Motol, Fac Med 2, Prague, Czech Republic
[13] Radboud UMC, Nijmegen, Netherlands
[14] Univ Childrens Hosp, Louvain, Belgium
[15] Childrens Mem Hlth Inst, Warsaw, Poland