TREM1 and infection: P. gingivalis has been shown to induce TREM1 gene expression (88), and it is therefore possible that carriers of the TREM1 AD–associated allele have a reduced ability to respond to infection by P. gingivalis. In addition, TREM1 is a target for gingipain proteolysis and degradation, with data showing that Rgp can cleave soluble TREM1 from the cell surface and that Kgp can degrade TREM1, actions that could induce chronic inflammation (88).