1. From the Institutes of Hematology and Internal Medicine, University of Perugia, Perugia; the Institute of Pathology, Niguarda Hospital, Milan, Italy; the Institute of Pathology, University of Bologna, Bologna, Italy; the Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY; and the Institute of Pathology, Benjamin Franklin University, Berlin, Germany.