[1] Univ Calif San Diego, La Jolla, CA 92093 USA
[2] Univ Hosp Tuebingen, Tubingen, Germany
[3] UCL, Sch Med, Div Rheumatol Allergy & Immunol, London, England
[4] Univ Amsterdam, Acad Med Ctr, Amsterdam, Netherlands
[5] Univ Hosp Basel, Rheumatol, Basel, Switzerland
[6] Novartis Pharma AG, Basel, Switzerland
[7] Univ N Carolina, Gillings Sch Global Publ Hlth, Chapel Hill, NC 27515 USA