p-ANCA of undefined specificity in ulcerative colitis: correlation to disease activity and therapy.

Sera of 108 patients with chronic inflammatory bowel disease (IBD) and 13 sera from patients with other gastrointestinal diseases were screened for antibodies against neutrophil cytoplasmic antigens (ANCA) by an indirect immunofluorescence test. 37 out of 64 sera (58%) from patients with ulcerative colitis (UC) produced a fine granular and perinuclear ANCA staining pattern ("snowdrift-like" p-ANCA) clearly different from the cytoplasmic ANCA fluorescence (c-ANCA) seen in active Wegener's granulomatosis (WG) and the typical p-ANCA pattern produced by anti-myeloperoxidase (MPO) autoantibodies. Only 1 of 44 sera from patients with Crohn's disease (CD) and none of the control sera showed positive "snowdrift-like" p- ANCA reactions. 31 out of the 37 p-ANCA positive sera (84%) were obtained from patients with high disease activity with and without longterm high dose steroids. p-ANCA titers became negative after longterm steroid therapy and following complete colectomy.