1. From the L. Sacco Institute of Biomedical Sciences, Pathology Unit, Milan, Italy (Drs Nebuloni, Carsana, Bonetto, Vago, and Costanzi, Mr Tosoni, and Ms Caldarelli); the Pathology Unit, Ospedale Maggiore della Carità, Institute of Medical Sciences, Novara, Italy (Drs Boldorini and Monga); and the Clinic of Infectious Diseases, University of Milan, Milan, Italy (Dr Abeli).