1. Department of Immunology, Division of Medicine, Faculty of Medicine, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, London W12 0NN, U.K.
2. Microscopy Laboratory, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, London W12 0NN, U.K.
3. Department of Nephrology and Transplantation, Endocrinology and Internal Medicine King's College London School of Medicine at Guy's, King's College, and St Thomas' Hospitals, London, U.K.
4. Department of Diabetes, Endocrinology and Internal Medicine King's College London School of Medicine at Guy's, King's College, and St Thomas' Hospitals, London, U.K.
5. Hepatobiliary Group, Institute of Cellular and Molecular Science, Barts and The Royal London Hospital, U.K.
6. Biogen Inc., Cambridge MA 02142.