aBrigham and Women's Hospital, Boston

bUMass Chan Medical School and UMass Memorial Medical Center, Worcester

cHarvard Medical School, Boston, Massachusetts, USA

Correspondence to Joerg Ermann, MD, Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, HBTM, Room 06002P, 60 Fenwood Road, Boston, MA 02115, USA. Tel: +1 617 525 1227; fax: +1 617 525 1010; e-mail: [email protected]