Background and aims: Phospholipase A(2) (PLA(2)) participates in the regulation of phospholipid metabolism and biosynthesis of eicosanoids, serum levels of PLA(2) are suggested to reflect the disease activity in patients with ulcerative colitis (UC). We examined the relationship between histological disease activity and serum levels of PLA(2) IIA and also clarified mucosal production sites of PLA(2) IIA by immunohistochemistry.
Patients and methods: Serum samples from 44 patients with UC, 125 with Crohn's diseases (CD), and 68 controls were studied. Biopsy specimens of colonic mucosa obtained from 23 patients with UC were used for assessment of histological activity. The histological score was determined active (1) or inactive (0), and the sum of each histological score from ten segments of the large intestine was assessed as disease activity. The levels of PLA(2) IIA in sera were measured by a radioimmunoassay kit using a specific monoclonal antibody; immunohistochemical study was performed using the same monoclonal antibody.
Results: The serum PLA(2) IIA levels in patients with UC and CD were significantly higher than those of controls. Serum PLA(2) IIA levels in UC were closely correlated with histological disease activity. Immunohistochemical study showed the production of PLA(2) IIA by the polymorphonuclear cells, macrophages, and colonic epithelial cells.
Conclusion: Serum PLA(2) IIA is a good candidate for assessing disease activity in UC as one of clinical laboratory tests.