p-ANCA target antigens in ulcerative colitis

INTRODUCTION: Data about the nature and pathophysiological relevance of the target antigens reacting with perinuclear antineutrophil cytoplasmatic autoantibodies (p-ANCA) in ulcerative colitis are inconsistent and partly conflicting. In the majority of the previous studies only one singular potential target antigen was investigated. The present study aimed on the simultaneous assessment of five different p-ANCA subtypes in patients with ulcerative colitis and attempted to detect reactivity against one of the previously described antigens and to correlate specificity for different target antigens with clinical features of the disease. METHODS: Sera from 61 patients with ulcerative colitis and from 56 healthy controls were tested using indirect immunofluorescence and enzyme-linked immunosorbent assays specific for elastase, lactoferrin, cathepsin G, myeloperoxidase and bactericidal permeability increasing protein (BPI). p-ANCA subtypes were correlated with clinical features of ulcerative colitis like disease extent or presence of extraintestinal manifestations. Moreover, a possible correlation to current immunosuppressive therapy was evaluated. RESULTS: In 46% (28/61) of patients with ulcerative colitis and in 4% (2/56) of the controls p-ANCA were detected. p-ANCA subtypes were distributed as follows: 26% (16/61) anti-BPI. 16% (10/61) anticathepsin G, 15% (9/61) antielastase, 7% (4/61) antilactoferrin, 5% (3/61) antimyeloperoxidase. Presence of anticathepsin G antibodies was negatively correlated with immunosuppressive therapy. No further correlations between p-ANCA subtypes and clinical characteristics were observed. DISCUSSION: p-ANCA subtypes in inflammatory bowel disease react with a variety of different target antigens and are not correlated with clinical features of the disease.