Jee Young Lee, et al. tissue disease. Rheum Dis Clin North Am 2005;31:549- 65, viii. 14. Scott DL, Kingsley GH. Tumor necrosis factor inhi- bitors for rheumatoid arthritis. N Engl J Med 2006;355: 704-12. 15. Shanahan JC, St Clair W. Tumor necrosis factor-alpha blockade: a novel therapy for rheumatic disease. Clin Immunol 2002;103:231-42. 16. Rudwaleit M, Baraliakos X, Listing J, Brandt J, Sieper J, Braun J. Magnetic resonance imaging of the spine and the sacroiliac joints in ankylosing spondylitis and undifferentiated spondyloarthritis during treatment with etanercept. Ann Rheum Dis 2005;64:1305-10. Yonsei Med J Vol. 49, No. 1, 2008