Previous studies have also investigated the pathogenic mechanisms by which C. concisus may contribute to the development of the associated intestinal and esophageal diseases, including the induction of proinflammatory cytokines such as interleukin 8 (IL-8) and tumor necrosis factor alpha (TNF-α), epithelial cell death, immunmodulators MD-2 and programmed death-ligand 1 (PD-L1), as well as enhancing the responses of epithelial cells and macrophages to commensal bacterial species (Lee et al., 2021). Here, TNF is linked to esophagitis.