IL1B and colitis: In the discussion above we have already encountered one such model, DSS-colitis in mice with caspase-12 deficiency, i.e., mice lacking an inhibitor of the NLRP3 inflammasome and of caspase-1 and have seen that this abnormality gives rise to increased NLRP3 activity causing less severe acute DSS-colitis and more severe chronic DSS-colitis reflecting the relative effect of NLRP3 and caspase-1 hyperactivity on IL-1β and IL-18, respectively.