LACK OF EFFECT OF ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES ASSOCIATED WITH ULCERATIVE-COLITIS ON SUPEROXIDE ANION PRODUCTION FROM NEUTROPHILS

Background-Antineutrophil cytoplasmic antibodies (ANCAs) from patients with vasculitidis can induce neutrophils to release oxygen radicals i n vitro. ANCAs with a perinuclear pattern of immunefluorescence are fo und in most patients with ulcerative colitis, but several findings are against ANCAs having a pathogenetic role in this disease. Aims-To eva luate the influence of ANCAs associated with ulcerative colitis on the respiratory burst activity of neutrophils. Patients-Serum samples wer e obtained from 14 patients with ulcerative colitis, seven of whom sho wed positivity for p-ANCAs, three patients with vasculitidis, two with positivity for p-ANCAs, and one for c-ANCAs, and seven healthy volunt eers. Methods-A positive ANCA serology was determined with a standard indirect immunofluroescence assay. Purified immunoglobulins (IgGs) wer e prepared from serum samples by DEAE-Affigel blue chromatography. Hum an neutrophils were prepared by dextran-Ficoll-Hypaque separation. Sup eroxide anion (O-2-(.)) generation was measured by following the super oxide dismutase inhibitable reduction of ferricytochrome. Results-Ther e were no significant differences among samples from ulcerative coliti s IgG p-ANCA positive, ulcerative colitis IgG p-ANCA negative patients , and controls on O-2-(.) production, whereas ANCA positive IgG from v asculitidis significantly enhanced O-2-(.) release (p<0.001). Conclusi ons-p-ANCAs associated with ulcerative colitis have no effect on the r espiratory burst activity of normal human neutrophils in vitro. These results reinforce the hypotheses that ANCAs are unlikely to contribute to the pathogenesis of ulcerative colitis.