In a second approach addressing the regulatory function of BS-NOD2 in Blau syndrome and an approach also used in prior studies, we evaluated the ability of NOD2 ligand (MDP) administration to ameliorate DSS-colitis in mice bearing a knock-in mutation in the NBD of NOD2 (KI mice) similar to that found in patients with BS. Here, NOD2 is linked to Blau syndrome.