TNF and inflammatory bowel disease: One study showed that the serum levels of NAMPT are increased in patients with IBD who fail to respond to anti‐TNF therapy and decreased in patients who are responsive to these therapies.[16] A study on anti‐TNF therapy for UC showed that NAMPT could be used to predict drug non‐responsiveness.[17] However, whether NAMPT affects the efficacy of UC anti‐TNF therapy by regulating the NAD+ salvage pathway and the correlation between the gut microbiota and NAD+ metabolism has not yet been elucidated.