1. Department of Hematology and Immunology, College of Medicine, University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu, Nigeria
2. Department of Hematology and Blood Transfusion, College of Medicine, University of Benin, Benin City Nigeria, Nigeria
3. Department of Pediatrics, College of Medicine, University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu, Nigeria