The following Hospitals and Physicians participated in the study: First Department of Internal Medicine, National University of Athens, Medical School, “Laiko” General Hospital (D. Loukopoulos, A. M. Tsimberidou, N. Viniou, N. Stavroyianni, J. Meletis, C. Constantopoulos, E. Variami, T. Andreopoulos, Y. Rombos, and X. Yataganas); Department of Clinical Propedeutic National University of Athens Medical School, “Laiko” General Hospital (P. Panagiotidis); Second Department of Internal Medicine, National University of Athens Medical School, Hippokration General Hospital (Th. Kalmantis and M. Belegrati); Department of Internal Medicine, Division of Hematology,University Hospital of Patras, Rion-Patras (N. Zoumbos, T. Matsouka, M. Tiniakou, A. Symeonidis, A. Kourakli, and P. Zikos); First Propedeutic Department of Medicine “AHEPA” University Hospital, Thessaloniki (A. Papadopoulos); Department of Hematology, Regional General Hospital of Athens “G. Gennimatas” (T. Marinakis, A. Galanopoulos, E. Michali, and N. Anagnostopoulos); Department of Hematology, “Benizelio” General Hospital, Heraklion, Crete (P. Iliakis); Department of Hematology, “Theagenion” Cancer Center, Thessaloniki (M. Papaioannou, J. Christakis, J. Korantzis, and A. Lazaridou); Department of Hematology, “401” General Army Hospital, Athens (D. Kolokithopoulos and C. Poziopoulos); Department of Hematology, Demokriteion University Hospital of Alexandroupolis, Thrace (G. Bourikas and K. Tsatalas); Department of Hematology, Crete School of Medicine, University Hospital, Heraklion, Crete (G. D. Eliopoulos and H. A. Papadaki); “Metaxa” Cancer Hospital, Athens (C. Megalakaki, B. Seitanidis, and M. Hatziyanni); University of Ioannina Hospital, Ioannina (K. L. Bourantas); Hematology Clinic, “HYGEIA” Diagnostic and Therapeutic Center, Athens (A. Papagiannis, Barbarousi, and G. Karianakis); Hematology Clinic Transplantation Unit, “Evangelismos” General Hospital, Athens (M. Nikiforakis, A. Skandali, N. Charchalakis, and N. Karakasis); Hematology Clinic, Transplantation Unit, “G. Papanikolaou” General Hospital, Thessaloniki (A. Fassas, A. Anagnostopoulos, and I. Sakellari.); and Laboratory of Immunology and Hematology, “G. Gennimatas” General Hospital (A. Tasiopoulou, E. Griva, E. Goumakou, G. Paterakis, G. Stavroupoulou-Giokas, and G. Androutsos).