[1] Univ Coll London Hosp NHS Fdn Trust, Dept Haematol, London, England
[2] UCL, Dept Haematol, Haemostasis Res Unit, 1st Floor,51 Chenies Mews, London WC1E 6HX, England
[3] UCL, Ctr Rheumatol, Div Med, London, England
[4] Univ Coll London Hosp NHS Fdn Trust, Dept Rheumatol, London, England