TNF and ankylosing spondylitis: Also, 265 (51.0%) of the patients were receiving anti TNF therapy due to the diagnosis of ankylosing spondylitis, 175 (33.7%) due to rheumatoid arthritis, 35 (6.7%) due to Crohn's disease, 10 (1.9%) due to ulcerative colitis, 21 (4.0%) due to psoriatic arthritis and 14 (2.7%) due to psoriasis vulgaris (figure 1).