[1] Unispital Basel, Rheumatol, Basel, Switzerland
[2] Univ Basel Hosp, Rheumatol, CH-4031 Basel, Switzerland
[3] UCL, Sch Med, London W1N 8AA, England
[4] UCL, London, England
[5] Univ Calif San Diego, San Diego, CA 92103 USA
[6] Univ Klinikum Tubingen, Klin Kinder & Jugendmed, Tubingen, Germany