TNF and irritable bowel syndrome: Specifically, IBS patients exhibit reduced gut microbiota diversity accompanied by dysbiosis (e.g., decreased Bacteroides, increased Escherichia coli), where pathogen‐derived metabolites like LPS activate intestinal mucosal TLR4 receptors, inducing macrophages and DCs to secrete IL‐6 and TNF‐α; concurrently, diminished production of Bacteroides‐derived SCFAs compromises their anti‐inflammatory protective effects on enteric neurons [317].