EFFECT OF PROCTOCOLECTOMY ON SERUM ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES IN PATIENTS WITH CHRONIC ULCERATIVE-COLITIS

Aims-To study the effect of proctocolectomy on the antineutrophil cyto plasmic antibody (ANCA) titres in association with ulcerative colitis. Methods-Serum samples were taken from 15 patients with ulcerative col itis immediately before and at a mean of 24 months after proctocolecto my. Indirect immunofluorescence for ANCA and enzyme immunoassays for m yeloperoxidase and proteinase-3 antibodies were employed. A liver biop sy was taken from every patient during the proctocolectomy, and serum liver enzyme activities were also determined. Results-Before proctocol ectomy, 13 of the 15 patients had perinuclear antineutrophil cytoplasm ic antibodies (p-ANCA). Additionally, one patient had a low titre of c lassical cytoplasmic ANCA and one had granulocyte specific antinuclear antibodies. After proctocolectomy, the ANCA titres decreased in 10 pa tients, in two of whom they became negative. The titres remained the s ame in four patients with positive ANCA and increased twofold in one p atient. Only one patient was proteinase-3 antibody positive and all 15 patients were myeloperoxidase antibody negative. The clinical conditi on improved in all patients, irrespective of the ANCA status after pro ctocolectomy. Seven patients, all of whom were positive for p-ANCA bef ore proctocolectomy, had histological liver abnormalities. No correlat ion was observed between serum liver enzyme levels and ANCA staining p atterns or titres. Conclusions-Proctocolectomy decreased the ANCA titr es in the majority of our patients, suggesting that reduction of the i nflammation or the available antigenic material modifies the immune di sturbance related to ulcerative colitis.