Background and aim: Monitoring of mucosal inflammation in inflammatory bowel disease (IBD) is of major importance. New noninvasive markers for intestinal inflammation are needed. Previous studies have reported that pancreatitis-associated protein (PAP) correlates with clinical activity in IBD subgroups. Our aim was to investigate the correlation of serum and fecal PAP with clinical and biochemical parameters of disease activity in a real-life IBD cohort.
Patients and methods: Two hundred and five consecutive IBD patients were enrolled. Clinical disease activity was scored by the Harvey-Bradshaw Index or the Simple Clinical Colitis Activity Index; also, C-reactive protein (CRP), erythrocyte sedimentation rate, and fecal calprotectin were determined. As surrogate for endoscopy, a combination score of clinical indices with CRP or calprotectin was used to define active disease. Fecal and serum PAP were measured by ELISA.
Results: The median serum and fecal PAP did not differ in Crohn's disease (CD) or ulcerative colitis (UC) patients with active compared with inactive disease according to clinical activity indices. Defining active disease by a combination score of Harvey-Bradshaw Index of more than 4 and CRP of more than 5 mg/l or calprotectin more than 250 µg/g, serum PAP (P=0.01), but not fecal PAP (P=0.32), was significantly higher in active than inactive CD patients. Area under the curve of the corresponding receiver operating curve (ROC) was 0.64. No differences were found in serum or fecal PAP levels using the combination score for active disease in UC.
Conclusion: Serum but not fecal PAP was higher in active compared with nonactive CD and may reflect mucosal inflammation in CD, but not in UC. However, the accuracy of serum PAP for the diagnosis of active disease was poor, and therefore, serum PAP does not seem to have additional value compared with the current noninvasive markers.