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

BACKGROUND/AIMS: Increased mucosal concentration of bactericidal/permeabili ty-increasing protein (BPI) has been shown in inflammatory bowel diseases. The purpose of the present study was to investigate the relationship betwee n the mucosal concentration of BPI and the grade of mucosal inflammation in ulcerative colitis. METHODOLOGY: Samples of colonic mucosa from 12 patients with ulcerative col itis and from 8 control patients were studied. The concentration of BPI in tissue extracts was measured by a time-resolved fluoroimmunoassay. The conc entration of BPI was compared between samples with histological inflammator y changes of different severity. BPI was localized in tissue sections by im munohistochemistry. RESULTS: The concentration of BPI was higher (p<0.001) in samples of coloni c mucosa from patients with ulcerative colitis (median: 3.2 mu g/g, range: 0.3-22.6 mu g/g) than in control samples (0.4 mu g/g, 0.1-0.6 mu g/g,). Mor eover, the concentration of BPI was higher (p=0.015) in samples with severe inflammation (2.5 mu/g, 0.3-22.6 mu g/g) than in those with mild inflammat ion (0.5 mu/g, 0.3-2.5 mu g/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 muco sa and stroma of the colonic wall. CONCLUSIONS: The concentration of BPI is increased in the colonic mucosa of patients with ulcerative colitis. The increase in the concentration of BPI in colonic mucose seems to be closely associated with the inflammatory act ivity of ulcerative colitis.