To test the hypothesis that enhanced epithelial disruption in the intestine is a present marker in patients with psoriasis, we measured intestinal fatty acid binding protein (I-FABP) and apoptotic index, the ratio of caspase-cleaved cytokeratin 18 fragment (ccCK 18) and total cytokeratin 18 (CK18) in the sera. Here, KRT18 is linked to psoriasis.