IL-18 overproduction in NLRC4^T337S/T337Smice derives from IECs and induces proliferation and major histocompatibility complex II upregulation. (A) Serum IL-18 concentration in bone marrow chimeras as depicted. Values at 0 time point represent serum concentration in donor mice. *P < .05 for all comparisons of top lines to bottom lines; repeated measures ANOVA with Tukey test for multiple comparisons. Representative of 2 experiments with at least 4 mice per group. (B) Serum IL-18 in Il18^flox/flox mice of the indicated genotypes. (C) Mice were injected with EdU and histologically evaluated 4 hours later for the proportion of EdU positive (green) cells among all villous cells (4′,6-diamidino-2-phenylindole). Original magnification ×200. Analysis by Student t test of pooled data from 3 separate experiments. Each point represents a distinct organ. (D) Genes most differentially upregulated (red) or downregulated (blue) in NLRC4^T337S/T337S duodenal epithelium by RNA-seq; see also Data supplements F and G.