TLR4 and mucositis: These DAMPs stimulate TLRs on neighboring epithelial cells and immune cells, and induce immune activation19 causing mucosal damage and barrier dysfunction.20 Especially TLR2, TLR4, and TLR9 activation has been found to play a role in intestinal mucositis development, and a deficiency in these receptors was found to be protective against mucositis.21, 22