11.   Perinuclear antineutrophil cytoplasmic antibody screening was performed in a blind prospective transversal setting.

12.   The standard antineutrophil cytoplasmic antibodies indirect immunofluorescence assay was performed in two laboratories.

13.   No significant relationship was found between positivity of perinuclear antineutrophil cytoplasmic antibodies and ulcerative colitis activity.

14.   Our resultsconfirm the presence of a perinuclear antineutrophil cytoplasmic antibody negative subgroup of ulcerative colitis patients.

15.   They were indistinguishable from perinuclear antineutrophil cytoplasmic antibody positive ulcerative colitis patients.

16.   No correlation was found between perinuclear antineutrophil cytoplasmic antibody positivity and localisation or extent of ulcerative colitis.

17.   The reaction of perinuclear antineutrophil cytoplasmic antibody titre to medication is controversial.

18.   Disappearance of perinuclear antineutrophil cytoplasmic antibodies after treatment with corticosteroids has been reported in a small number of patients.

19.   The pathophysiological importance of the ulcerative colitis associated perinuclear antineutrophil cytoplasmic antibodies is still poorly understood.

20.   The presence of perinuclear antineutrophil cytoplasmic antibodies in unaffected family members of ulcerative colitis patients favours this view.