TNF and ankylosing spondylitis: In particular, anti-tumor necrosis factor (TNF)-α antibody therapy has seen wide use for rheumatoid arthritis (RA) (Bathon et al., 2000), psoriasis (Leonardi et al., 2003), ankylosing spondylitis (Gorman et al., 2002), and inflammatory bowel disease (Rutgeerts et al., 2005).