Circulating immune complexes in ulcerative colitis. I. Correlation to disease activity.

Twenty-two patients with ulcerative colitis were studied for occurrence of circulating immune complexes (IC) by three independent methods, a complement consumption assay, a Clq-binding assay and a RF-binding assay. All patients had the disease in an active stage when the study was initiated. Positiveness in two or more test systems was considered to indicate the presence of IC in the serum sample examined. By this criterion, circulating complement-fixing IC were detected in eight out of the twenty-two patients (36%; 95% confidence limits: 17–60%). IC were detected most frequently in patients with long-standing disease. A correlation between the occurrence of circulating IC and disease activity, in terms of visible blood in faeces and number of bowel movements per day, was demonstrated. Cytological examination of the rectal mucus indicated moderate to severe inflammation in all IC-positive patients. Six out of the eight IC-positive patients were subjected to short-term glucocorticosteroid treatment; only one of these patients exhibited circulating IC and high disease activity after treatment —this patient was colectomized. Salazosulphapyridine treatment showed no relation to IC occurrence. Four out of the twenty-two patients (18%; 95% confidence limits 5–40%) were positive for organ non-specific antinuclear factor (ANF), but the presence of ANF did not correlate with circulating IC. Neither was any significant correlation between antibody titres to O119:B14 antigen and IC occurrence demonstrable.