1. Immunosenescence Unit, Department of Pathobiology and Biomedical Methodology, University of Palermo, Palermo, Italy.
2. Biochemistry Clinic, University of Sassari, Sassari, Italy.
3. INRCA Geriatric Department, Laboratory of Clinical Epidemiology, Florence, Italy.
4. Operative Unit of General Medicine, Padova Hospital, Padova, Italy.
5. Department of Experimental Pathology, University of Bologna, Bologna, Italy.