1. Department of Clinical and Experimental Medicine Section of Hematology and Clinical Immunology, University of Perugia Medical School, I-06100 Perugia, Italy
2. Department of Biomedical Sciences and Human Oncology Section of Internal Medicine and Clinical Oncology, University of Bari Medical School, I-70124 Bari, Italy
3. Immunohematology and Blood Transfusion Service Perugia General Hospital, I-06100 Perugia, Italy
4. Section of Medical StatisticsUniversity of Bari Medical School, I-70124 Bari, Italy