Deletion of TLR5 (but not other TLRs or MyD88) was also reported to lead to spontaneous colitis, but interestingly this was reversed by concurrent deletion of TLR4 in double knockout animals [19], suggesting that specific PAMPs can serve as either protective or damaging agents in different IBD models, depending on the context of their exposure. This evidence concerns the gene TLR4 and inflammatory bowel disease.