Tff2 mRNA was undetectable in colon of wild-type and CD2–Tff2 mice treated with AOM/DSS; however, in contrast to decreased Tff2 mRNA in the spleen of wild-type mice, the level of Tff2 mRNA in the spleens of CD2–Tff2 mice remained quite high (Supplementary Fig. 4c). Here, TFF2 is linked to infectious otitis media.