[1] Univ Manchester, Sch Translat Med, Arc Epidemiol Unit, Manchester M13 9PT, Lancs, England
[2] Cent Manchester Univ Hosp NHS Trust, Kellgren Ctr Rheumatol, Manchester, Lancs, England
[3] Manchester Childrens Univ Hosp NHS Trust, Kellgren Ctr Rheumatol, Manchester, Lancs, England
[4] Univ Birmingham, Div Immun & Infect, Birmingham B15 2TT, W Midlands, England
[5] Royal Natl Hosp Rheumat Dis, Bath BA1 1RL, Avon, England
[6] Norfolk & Norwich Univ Hosp, Dept Rheumatol, Norwich, Norfolk, England