The β-Defensins are an integral part of the congenital immune system and contribute with their antimicrobal effect to the barrier function of the intestinal epithelial cells.

A decreased β-Defensin 2 expression can, for example, be observed in the intestinal mucous of patients with Crohn's disease. The defense system of the mucous membrane is therefore restricted and allows an increased invasion of bacteria, which could possibly lead to a typical infection in Crohn's disease patients.