In 2016, Bek et al. performed a meta-analysis study that confirmed that nine polymorphisms in eight genes (TLR2, CD14, LY96, TNF, TNFRSF1B, TNFAIP3, IL1RN, and IL17A) were not associated with anti-TNF therapy in patients with IBD. This evidence concerns the gene IL1RN and inflammatory bowel disease.