1. Division of Infection and Immunity
2. U.O. Gastroenterologia ed Epatologia, Spedali Riuniti di Santa Chiara, I-56124 Pisa, Italy
3. Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
4. Institute of Hepatology,
5. Gastroenterology Unit, Fondazione Policlinico, University of Milan, 20122 Milan, Italy
6. Nuffield Department of Clinical Medicine and The Jenner Institute, University of Oxford, Oxford OX3 9DU, UK
7. Centre for Sexual Health and HIV Research, University College London, London W1T 4JF, UK