Association of antineutrophil cytoplasmic antibodies with resistance to treatment of left-sided ulcerative colitis: Results of a pilot study

Objective: To determine the frequency of antineutrophil cytoplasmic antibodies with perinuclear staining in patients with treatment-resistant left-sided ulcerative colitis. Methods: We studied four groups: treatment-resistant left-sided ulcerative colitis, treatment-responsive left-sided ulcerative colitis, ulcerative colitis historical controls, and healthy control subjects. Antineutrophil cytoplasmic antibodies were detected by enzyme-linked immunosorbent assay, and positive results were confirmed by demonstration of a perinuclear staining pattern by indirect immunofluorescence assay. Results: The frequency of perinuclear antineutrophil cytoplasmic antibodies was significantly greater in treatment-resistant left-sided ulcerative colitis (90%:) than in treatment-responsive left-sided ulcerative colitis (62%) (P = 0.03) or in ulcerative colitis historical controls (60%). Conclusion: The increased frequency of perinuclear antineutrophil cytoplasmic antibodies in treatment-resistant left-sided ulcerative colitis suggests a possible association between these antibodies and relative resistance to medical therapy in patients with ulcerative colitis.