FOXO1 and periodontitis: The importance of an adequate host response to bacterial challenge has been shown by increased susceptibility to periodontitis in mice with genetic deletion of specific genes that regulate leukocyte recruitment such as Icam-1, P-selectin, Beta2-integrin/CD18; recognition of bacteria by TLR2, TLR4, Lamp-2; immune modulation by Cxcr2, Ccr4, IL-10, OPG, IL1RA, TNF-α receptor, IL-17 receptor, Socs3, Foxo1; and deletion of genes that encode proteolytic enzymes including Mmp8 and Plasmin (42).