1. Research Institute Children's Cancer Center; Hamburg Germany
2. Center for Rheumatic Disease; Bad Bramstedt Germany
3. Department of Transfusion Medicine; University Medical Center Hamburg-Eppendorf; Hamburg Germany
4. Department of Medical and Surgical Sciences for Children & Adults; University Hospital of Modena and Reggio Emilia; Modena Italy
5. Department of Pediatric Hematology and Oncology; University Medical Center Hamburg-Eppendorf; Hamburg Germany