1. Division of Rheumatology, Department of Medicine, Daejeon Rheumatoid and Degenerative Arthritis Center, Chungnam National University Hospital, Daejeon, Republic of Korea;
2. Department of Microbiology, College of Medicine, Konyang University, Daejeon, Republic of Korea;
3. Department of Rheumatology, Cheongju St. Mary's Hospital, Cheongju, Republic of Korea