Bactericidal/permeability-increasing protein in colonic mucosa in ulcerative colitis

Increased mucosal concentration of bactericidal/permeability-increasing protein (BPI) has been shown in inflammatory bowel diseases. The purpose of the present study was to investigate the relationship between the mucosal concentration of BPI and the grade of mucosal inflammation in ulcerative colitis.Samples of colonic mucosa from 12 patients with ulcerative colitis and from 8 control patients were studied. The concentration of BPI in tissue extracts was measured by a time-resolved fluoroimmunoassay. The concentration of BPI was compared between samples with histological inflammatory changes of different severity. BPI was localized in tissue sections by immunohistochemistry.The concentration of BPI was higher (p0.001) in samples of colonic mucosa from patients with ulcerative colitis (median: 3.2 micrograms/g, range: 0.3-22.6 micrograms/g) than in control samples (0.4 microgram/g, 0.1-0.6 microgram/g,). Moreover, the concentration of BPI was higher (p = 0.015) in samples with severe inflammation (2.5 mu/g, 0.3-22.6 micrograms/g) than in those with mild inflammation (0.5 mu/g, 0.3-2.5 micrograms/g). The concentration of BPI in mucosal samples correlated well with the degree of histological inflammation (Spearman R = 0.70, p = 0.01). BPI was localized in polymorphonuclear leukocytes in the mucosa and stroma of the colonic wall.The concentration of BPI is increased in the colonic mucosa of patients with ulcerative colitis. The increase in the concentration of BPI in colonic mucosa seems to be closely associated with the inflammatory activity of ulcerative colitis.