In PBLs, the frequencies of CD40+ and CD80+ cells were significantly increased in DSS-treated ERAP1+/− mice (p < 0.01) and in sulfasalazine-treated ERAP1+/− colitis mice (p < 0.05) compared to ERAP1+/− healthy controls (Figures 3A, B). This evidence concerns the gene ERAP1 and colitis.