TNF and ankylosing spondylitis: Despite of the potential adverse effects and limitations, the licensed anti-TNF-α monoclonal Abs, adalimumab and infliximab, have proved to be remarkably successful as an injectable protein-based therapy in clinical treatment of immune-mediated inflammatory diseases (IMID), such as rheumatoid arthritis (RA), Crohn's disease, inflammatory bowel disease (IBD), psoriatic arthritis (PsA), and ankylosing spondylitis(AS) [16].