1. Pediatric Oncology Department and Pediatric Stem Cell Transplantation Unit Children's Cancer Hospital Egypt (CCHE 57357) Cairo Egypt
2. Pediatric Oncology Department and Hematopoietic Stem Cell Transplantation National Cancer Institute (NCI) Cairo University Cairo Egypt
3. Microbiology Department Children's Cancer Hospital Egypt (CCHE 57357) Cairo Egypt
4. Clinical Pathology Department Cairo University Cairo Egypt
5. Biostatistics and Epidemiology Unit Research Department Children's Cancer Hospital Egypt (CCHE 57357) Cairo Egypt
6. Pediatric Hematology-Oncology and Stem Cell Transplantation Unit Dana Farber/Children's Hospital Cancer Care Center Boston MA USA