1. Rheumatology Unit, Imperial College School of Medicine, St Mary's Hospital, London, UK; 21 Queen Anne's Gardens, Ealing, London W5 5QD, UK.;
2. Neurovascular Medicine Unit, Imperial College School of Medicine, St Mary's Hospital, London, UK
3. Rheumatology Unit, Imperial College School of Medicine, St Mary's Hospital, London, UK
4. Department of Mathematics, Imperial College, London, UK