1. Center for Rheumatic Disease in Kang-Nam St Mary's Hospital, Division of Rheumatology
2. Division of Pulmonology, Department of Internal Medicine, The Catholic University of Korea, Seoul, South Korea
3. Center for Rheumatic Disease in Kang-Nam St Mary's Hospital, Division of Rheumatology: Division of Rheumatology, Department of Internal Medicine, The School of Medicine, The Catholic University of Korea, The Center for Rheumatic Disease in Kang-Nam St. Mary's Hospital, # 505 Banpo-Dong, Seocho-Ku, Seoul, 137-040, South Korea.