Background: The aim of the present study was to determine the prevalence and diagnostic usefulness of antineutrophil cytoplasmic antibodies (ANCA) in a Spanish population of patients with inflammatory bowel disease from the province of Tarragona.
Patients and methods: One hundred and fifty-six sera obtained from 116 patients with inflammatory bowel disease (75 ulcerative colitis and 41 Crohn's disease) and 40 healthy controls were tested using an indirect immunofluorescence assay.
Results: ANCA were detected in 65% of patients with ulcerative colitis but in only 12% of patients with Crohn's disease (p < 0.01), and 2.5% of control subjects (p < 0.01). The overall sensitivity of the test for the diagnosis of ulcerative colitis was 65% with a specificity of 88% and a positive predictive value of 91%. Among patients with ulcerative colitis there was no relationship between the presence or titre of ANCA and the duration, the clinical course, the extent, the disease activity or the need for medical treatment.
Conclusions: In the population studied, ANCA occur more commonly in ulcerative colitis than in Crohn's disease, as reported in other populations. Their determination in patients with inflammatory bowel disease may be useful to differentiate ulcerative colitis from Crohn's disease.