1. Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine , Tokyo, Japan
2. The Japan Rheumatism Friendship Association , Tokyo, Japan
3. Department of Allergy and Clinical Immunology, Chiba University Hospital , Chiba, Japan
4. Department of Rheumatology, Kawasaki Medical School , Kurashiki, Japan
5. Department of Orthopaedic Surgery, Saitama Medical University , Saitama, Japan
6. First Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health , Kitakyushu, Japan
7. Saitama Medical University , Saitama, Japan