Dietary antigens in Crohn's disease: antibodies to porcine pancreatic amylase.

Abstract

There is no clear evidence that dietary proteins aggravate Crohn's disease (CD). We aimed to clarify the antibody response to dietary proteins in CD. Antibody to porcine pancreatic amylase (PPA) a protease-resistant dietary protein (anti-PPA), was examined in CD patients (N = 104), ulcerative colitis (UC) patients (N = 85), and healthy controls (N = 83), and its relationship with the clinical characteristics of CD was investigated. Antibodies to casein and ovalbumin, anti-Saccharomyces cerevisiae antibodies (ASCA), and antibodies to I2 from Pseudomonas fluorescens (anti-I2) were also examined. Thirty-eight percent (39/104) of the CD patients expressed anti-PPA antibodies, and this percentage was significantly higher as compared with the control group (5%, 4/83) and the UC group (9%, 8/85) (P < 0.001). A significantly higher level of anti-PPA antibodies was detected in patients with "small bowel disease-dominant" CD than in those with "colitis-dominant" CD (P < 0.05). Antibodies to casein and ovalbumin were not specifically expressed in CD patients. As ASCA was detected in 33% and anti-I2 in 46% of the CD patients, 72% of the CD patients were found positive for at least one of the three antibodies including anti-PPA antibodies. CD patients showed a specific antibody response to PPA, as compared with UC patients and controls. There was a significantly higher level of anti-PPA antibody in patients with "small bowel disease-dominant" CD, suggesting that dietary proteins could play a role in the inflammatory response in CD patients with small bowel disease. Anti-PPA antibodies combined with ASCA/anti-I2 may be useful for the diagnosis of CD.