1. Center for Rheumatic Diseases, Japanese Red Cross Society Kagoshima Hospital, 2545 Hirakawa, Kagoshima 891-0133, Japan
2. Izumihara Rheumatoid Arthritis and Internal Medicine Clinic, Kagoshima, Japan
3. Eiraku Internal Medicine Clinic, Kagoshima, Japan
4. Yoshitama Rheumatoid Arthritis and Internal Medicine Clinic, Kagoshima, Japan