Immunological studies in ulcerative colitis. 3. Incidence of antibodies to colon-antigen in ulcerative colitis and other gastro-intestinal diseases.

The presence of anti-colon antibodies in sera from patients with ulcerative colitis was investigated with indirect haemagglutination and the fluorescent antibody procedure. The antigen was obtained from germ-free rats. There was a good correlation between the results obtained with both procedures. Of a group of 101 ulcerative colitis patients, 56% were found to have a haemagglutination titre of ≥ 1:16. In a group of forty-five age- and sex-matched healthy controls or surgical cases 13% had such titres. This difference was statistically significant. In an additional control group of patients with bronchial asthma, the incidence of elevated titres was higher than in the healthy controls but lower than in ulcerative colitis. Of 109 patients with other gastro-intestinal disorders (chronic diarrhoeas of unknown aetiology, bacillary dysentery, infections, cancer of colon and rectum, coeliac disease) only eight had a titre of ≥ 1:16. In fifteen South African patients with amoebic dysentery but of unknown clinical status, the incidence of elevated haemagglutination titres was also higher than in the healthy controls (33%). Of eighteen patients with regional enteritis, twelve (67%) had titres of 1:16 or higher. However, eleven out of these eighteen had lesions in both large and small intestine. Fluorescent antibody staining of rat colon sections confirmed these results. In ulcerative colitis, the incidence of elevated titres (≥ 1:16) was independent of the patients' age but was significantly higher in females older than 25 years than in male patients of the same age. In patients younger than 25 years, this difference between the sexes was less marked and statistically not significant. Colectomy (including pancoloproctectomy) was without influence on antibody titres, which sometimes were found to be elevated as long as 2–10 years after surgery. There was no significant correlation between antibody titres and duration or severity of the disease, the extent of colonic involvement and the occurrence of extra-colonic manifestations.