1. Internal Medicine and Hepatology Unit, University Campus Bio-Medico of Rome, Rome, Italy.
2. Liver Unit, Department of Internal Medicine, Clinica Universitaria de Navarrra, Pamplona, Spain.
3. Liver Unit, San Camillo-Forlanini Hospital, Rome, Italy.
4. Department of Clinical Pathology and Microbiology, University Campus Bio-Medico of Rome, Rome, Italy.