CD40 and colitis: To get further insight into the complex interplay of microbiota, adaptive immunity and inflammation in CD40-mediated colitis, we first determined the disease onset in DC-LMP1/CD40 mice by measuring fecal lipocalin-2, a sensitive noninvasive inflammatory marker.36 Lipocalin-2 levels were significantly increased in DC-LMP1/CD40 mice starting from week 5 (Figure 1(a)), showing a very early disease onset because of constitutive CD40-signaling on DCs as published previously.24 To measure a potential impact on adaptive immunity, we analyzed IgG and IgA serum levels during colitis progression.