aStanford School of Medicine, Division of Immunology & Rheumatology, Palo Alto, California

bUniversity of Washington, Division of Rheumatology, Seattle, Washington

cStanford School of Medicine & Palo Alto VA Healthcare System, Division of Immunology & Rheumatology, Palo Alto, California, USA

Correspondence to Lorinda Chung, Stanford School of Medicine & Palo Alto VA Healthcare System, Division of Immunology & Rheumatology, 1000 Welch Road, Suite 203, Palo Alto, CA 94304, USA. Tel: +1 650 723 6961; e-mail: [email protected]