[1] Department of Medicine, University of Leuven
[2] Department of Clinical Sciences, London School of Hygiene and Tropical Medicine
[3] Mr Cardiothoracic Surgery, St George's Hospital, London
[4] Department of Pharmacology and Therapeutics, University of Leicester
[5] Division of Rheumatology, University of Colorado Health Sciences Center
[6] Pain Research Institute, Walton Hospital, Liverpool