1. Department of Internal Medicine and Rheumatology, Health Insurance Society of Hitachi Zosen, Innoshima General Hospital, Hiroshima, Japan
2. Department of Clinical Immunology and Rheumatology, Hiroshima University Hospital, Hiroshima, Japan
3. Division of Hematology, Department of Medicine, Kawasaki Medical School, Okayama, Japan
4. Department of Clinical Laboratory, Health Insurance Society of Hitachi Zosen, Innoshima General Hospital, Hiroshima, Japan