However, ileal CD is characterized by a specific decrease in Paneth cell alpha-defensins and defective Paneth cell-mediated host defense [42] which has been linked to the NOD2 genotype [43], although this finding is opposed by the results of a recent study [44], and additional modifiers of Paneth cell function such as XBP1 are involved [45]. Here, XBP1 is linked to Cowden disease.