1. Department of Medicine, Department of Statistical Science, and Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, England, UK
2. Molecular and Cellular Technologies, Molecular Discovery Research, GSK, Harlow, Essex CM19 5AW, England, UK
3. Kennedy Institute of Rheumatology, Imperial College London, London W6 8LH, England, UK
4. Department of Gastroenterology, University College London Hospital, London NW1 2BU, England UK