[1] Childrens Hosp Philadelphia, Div Rheumatol, Philadelphia, PA 19104 USA
[2] Univ Michigan, Div Pediat Rheumatol, Ann Arbor, MI 48109 USA
[3] Univ Penn, Perelman Sch Med, Dept Biostat Epidemiol & Informat, Philadelphia, PA USA
[4] Boston Childrens Hosp, Div Immunol, Boston, MA USA
[5] Harvard Med Sch, Boston, MA USA
[6] Univ Penn, Perelman Sch Med, Dept Pediat, Philadelphia, PA USA
[7] Childrens Hosp Philadelphia, Div Gastroenterol Hepatol & Nutr, Philadelphia, PA USA
[8] Univ Penn, Perelman Sch Med, Ctr Pediat Clin Effectiveness, Philadelphia, PA USA
[9] Childrens Hosp Philadelphia, Philadelphia, PA USA