1. From the Systemic Autoimmunity Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD (P.C.G.); and the Departments of Medicine (C.A.P.), Radiology (V.V.D.), and Pathology (J.A.F.), Massachusetts General Hospital, and the Departments of Medicine (C.A.P.), Radiology (V.V.D.), and Pathology (J.A.F.), Harvard Medical School — both in Boston.