ANTINEUTROPHIL ANTIBODIES IN FAMILIAL INFLAMMATORY BOWEL-DISEASE

Background/Aims: Antineutrophil cytoplasmic antibodies have been repor ted to occur more frequently in healthy first-degree relatives of pati ents with ulcerative colitis than in healthy controls. The aim of this study was to determine their prevalence in families in which more tha n one member was affected with inflammatory bowel disease. Methods: Wi th use of an indirect immunofluorescence method, 168 affected members and 197 unaffected first-degree relatives in 56 such families were stu died, Results: Antibodies were detected in 46% of patients with ulcera tive colitis without a positive family history and in 44% of those wit hin families with several affected members, There was no evidence of c lustering of antibodies in particular families. Within families in whi ch both ulcerative colitis and Crohn's disease coexisted, antibodies w ere detected primarily in patients with ulcerative colitis. Antibodies were seldom present (3%) in those patients with Crohn's disease, whet her they were familial or nonfamilial cases. Similarly, antibodies wer e seldom present (3%) in controls or the unaffected first-degree relat ives of patients with inflammatory bowel disease. Conclusions: Antineu trophil cytoplasmic antibodies ave associated with ulcerative colitis, and their presence is not increased in the first-degree relatives of patients with ulcerative colitis. They are move likely to be a consequ ence of the disease than a subclinical genetic disease marker.