1. National Institute for Health Research Biomedical Research Centre, University of Oxford, Oxford, United Kingdom;
2. Division of Infectious Diseases, University Hospital Berne and University of Berne, Berne, Switzerland;
3. Centre for Immunology, Infection and Evolution, Ashworth Laboratories, Edinburgh, United Kingdom;
4. Translational Gastroenterology Unit, Experimental Medicine, University of Oxford, Oxford, United Kingdom;
5. Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO;
6. Guys and St Thomas' National Health Service Trust/King's College London, Harrison Wing, St Thomas' Hospital, London, United Kingdom;
7. Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland;
8. Division of Infectious Diseases, University Hospital Basel, Basel, Switzerland; and
9. St Stephen's Centre, Chelsea and Westminster Hospital, London, United Kingdom