1. Liver Center, Gastroenterology Division, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
2. HIV Molecular Research Group, University College of Dublin, Ireland
3. Biostatistics Center, Massachusetts General Hospital, Boston
4. Department of Pathology, Massachusetts General Hospital, Boston
5. Department of Medicine, University of California, San Francisco
6. Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles