1. Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine Hokkaido University Sapporo Japan
2. Department of Rheumatology and Clinical Immunology Sapporo Medical University Sapporo Japan
3. Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan, and Department of Rheumatology and Infectious Diseases, School of Medicine Kitasato University Sagamihara Japan