[1] Harvard Med Sch, Brigham & Womens Hosp, Dept Dermatol, 221 Longwood Ave, Boston, MA 02115 USA
[2] Aarhus Univ Hosp, Dept Clin Immunol, Aarhus, Denmark
[3] Univ Penn, Ctr Clin Epidemiol & Biostat, Perelman Sch Med, Dept Med,Div Rheumatol, Philadelphia, PA USA
[4] Massachusetts Gen Hosp, Dept Neurol, Boston, MA USA
[5] Harvard Med Sch, Div Sleep Med, Boston, MA USA
[6] Harvard Med Sch, Brigham & Womens Hosp, Dept Dermatol & Med, Div Rheumatol, Boston, MA USA