CD200 and colitis: The disease activity index (DAI), which is based on the main features of colitis: weight loss, colon shortening, stool consistency, stool blood, and rectal bleeding, was decreased in Cd200−/− mice in comparison to WT mice (6.6 ± 0.4 vs. 8.7 ± 0.4, (p < 0.01, t-test) (Figure 1B).