Tumor necrosis factor alpha (TNF-alpha) promotes inflammatory responses, which, in turn, contribute to the clinical problems associated with many inflammatory disorders, including rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, psoriasis and refractory asthma. These diseases are sometimes treated with TNF-alpha inhibitors, including infliximab, adalimumab, etanercept, certolizumab pegol, or golimumab. Prolonged therapies with these TNF-alpha inhibitors may lead to development of neutralizing antibodies (NAbs), which may counteract the TNF-alpha antagonist activity of the drugs.