[1] Univ Alabama Birmingham, Birmingham, AL USA
[2] Uppsala Univ, Uppsala, Sweden
[3] Univ Ottawa, Ottawa, ON, Canada
[4] BC Chidrens Hosp, Vancouver, BC, Canada
[5] Hackensack Univ, Hackensack, NJ USA
[6] German Rheumatism Res Ctr Berlin, Berlin, Germany
[7] Karolinska Univ Hosp, Stockholm, Sweden
[8] Charite, Childrens Univ Hosp, Berlin, Germany
[9] Univ Nothern Norway, Tromso, Norway
[10] Hosp Garcia de Orta, Lisbon, Portugal
[11] Univ Manchester, Manchester, Lancs, England
[12] Ctr Hosp Porto, Oporto, Portugal