PRDM1 and colitis: The loss of body weight and colitogenic onset started at 12–13 weeks of age in NOD.LckCrePrdm1F/F mice, and 83% of these mice developed colitis at 25 weeks old, while B6.LckCrePrdm1F/F mice remained disease-free (Fig. 2a), suggesting a much higher Blimp-1 deficiency-mediated colitogenic susceptibility in NOD mice than in C57BL/6 mice.