1. From the Istituto di Ricerche Farmacologiche ‘Mario Negri,’ Milan; Section of Pathology and Immunology, Department Biotechnology, University of Brescia, Brescia, Italy; Serono Pharmaceutical Research Institute, Geneva, Switzerland; Istitute Dermopatico dell’Immacolata, Rome; Regina Elena Cancer Institute, Rome; University of Rome “La Sapienza,” Rome; Roche Milano Ricerche, Milan; and Istituto di Medicina Interna e Immunoallergologia, University of Florence, Florence, Italy.