1 Department of Immunology and Histocompatibility, University of Thessaly, Medical School, 41110 Biopolis, Larissa, Greece. Electronic address: maspel@med.uth.gr.
2 Department of Immunology and Histocompatibility, University of Thessaly, Medical School, Larissa, Greece.
3 Hematology Department, Papageorgiou General Hospital, Thessaloniki, Greece.