P129 USEFULNESS OF PROSTAGLANDIN E-MAJOR URINARY METABOLITE MEASUREMENT FOR THE DIFFERENTIATION BETWEEN CHRONIC ENTEROPATHY ASSOCIATED WITH SLCO2A1 GENE (CEAS) AND CROHN’S DISEASE

Chronic enteropathy associated with SLCO2A1 gene (CEAS) is a rare intractable disease characterized by persistent anemia and hypoproteinemia due to multiple small intestinal ulcers. Recently, we identified that the disease is caused by loss-of-function mutations of SLCO2A1 gene, encoding a prostaglandin transporter. Because clinical features of CEAS mimic those of Crohn’s disease (CD) with respect to intestinal ulcers and stenosis, a convenient screening test other than genetic analysis is required. Our preliminary study demonstrated higher urinary levels of prostaglandin metabolites in patients with CEAS than in healthy controls. In this study, we investigated the usefulness of prostaglandin E-major urinary metabolites (PGE-MUM) to discriminate CEAS from CD. Seventeen Japanese patients with CEAS and 97 CD patients were recruited. The diagnosis of CEAS was based on the published clinical criteria and genetic analysis. Urine samples were collected, and PGE-MUM concentration was measured by radioimmunoassay. Logistic regression analysis was used to calculate the odds ratio (OR). We used ROC analysis to determinate the optimal cut-off value of PGE-MUM. PGE-MUM concentration was significantly higher in CEAS group than in CD group (median 121 vs 21.7 μg/g×Cre, p < 0.0001). Crude OR of 1 log unit change for the PGE-MUM for the differentiation between CEAS and CD was calculated to be 7.46 (95% confidence interval [CI] 3.14–17.7). This association was also significant after adjusting confounding factors including age, gender, history of pulmonary disease, surgical history, and CRP (adjusted OR 21.1, 95%CI 4.72–94.4). The optimal cut-off value of PGE-MUM was determined to be 50.9 μg/g×Cre, which identified CEAS with 93.7% sensitivity and 80.4% specificity (area under the ROC curve 0.905). The measurement of PGE-MUM is considered to be a useful and convenient test for discriminating CEAS from CD.