TNF and inflammatory bowel disease: Monoclonal antibodies, particularly chimeric antibodies like Infliximab, can stimulate the production of ADA [87], which can lead to treatment inefficacy or secondary loss of response (Fig. 1), therefore, monitoring of serum ADAs and anti-TNF levels in case of > 3 μg/ml Infliximab therapy in IBD patients is an important parameter to optimum treatment response in IBD patients [88].