1. Department of Rheumatology, Sasebo City General Hospital, Sasebo 857-8511, Japan
2. Department of Immunology and Rheumatology, Division of Advanced Preventive Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8523, Japan
3. Clinical Research Center, Nagasaki University Hospital, Nagasaki 852-8501, Japan
4. Department of Rheumatology, National Hospital Organization Ureshino Medical Center, Ureshino 843-0393, Japan
5. Division of Hematology and Rheumatology, Department of Medicine, Nihon University School of Medicine, Tokyo 173-8610, Japan