RELATIONSHIP BETWEEN ANCA AND CLINICAL ACTIVITY IN INFLAMMATORY BOWEL-DISEASE - VARIATION IN PREVALENCE OF ANCA AND EVIDENCE OF HETEROGENEITY

Antineutrophil cytoplasmic antibodes (ANCA) are markers of necrotizing vasculitis. ANCA have been recently detected in the two forms of infl ammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn's dise ase (CD). To assess the possible role of ANCA in the diagnosis and man agement of IBD we studied the prevalence of ANCA at diagnosis and duri ng follow-up in a group of 89 IBD patients. The relationship between A NCA and clinical features of IBD was investigated. ANCA assayed by ind irect immunofluorescence were detected in 38/52 (73%) of the UC patien ts but only 6/37 (16.6%) of the CD patients (P<0.005) and in none of t he controls. In the UC group, but not in the CD group, there was a pos itive correlation between ANCA and disease activity. The sensitivity a nd specificity of ANCA for the diagnosis of UC were 73 and 83.7% respe ctively. The most commonly observed pattern of ANCA in IBD patients wa s perinuclear: in 84% of the UC and 66.6% of the CD patients positive for ANCA, respectively. However, careful comparison of IFL patterns re vealed some distinct features of IBD-associated ANCA when compared to vasculitis-associated ANCA. In addition, most ANCA positive sera from IBD patients were negative for antibodies to proteinase 3 and myeloper oxidase by ELISA. These results suggest that the autoantigens recogniz ed by ANCA are different in patients with IBD from those with necrotis ing vasculitis. (C) 1997 Academic Press Limited.