In studies using real-time RT–PCR, compared to normal control colonic mucosal samples, crypt epithelial cells isolated from inflamed ulcerative colitis (UC) and inflamed Crohn's colitis mucosal samples showed significantly increased expression of TLR-2 [median (range) fold increase (relative to mean, corrected to 1·0, of normal control cells): UC 3·18 (0·91–474·9), P = 0·003; Crohn's colitis 3·45 (0·75–10·51), P = 0·012; Fig. 1a] and TLR-4 [fold increase: UC 2·33 (0·40–10·07), P = 0·024; Crohn's colitis 1·71 (0·91–10·30), P = 0·042; Fig. 1b and Supporting information Table S2]. Here, TLR2 is linked to Crohn's colitis.