Decreased suppressor cell activity in inflammatory bowel disease.

Studies were performed on eleven patients with inflammatory bowel disease to determine if there was an alteration in concanavalin A (Con A) induced suppressor cell activity. Similar investigations were also performed on twenty-one control subjects and five patients with other inflammatory conditions. Supressor cells were generated by pre-incubation of peripheral blood mononuclear cells with a mitogenic concentration of Con A, followed by treatment with mitomycin C and alpha-methyl mannoside. Under these conditions, cells obtained from normal individuals are then capable of suppressing the Con A-stimulated blast transformation responses of fresh allogeneic lymphocytes in new cultures. We found that in twenty out of twenty-one control subjects, and all five patients with other inflammatory disorders, Con A-stimulated suppressor cell activity was demonstrable. Four patients with inflammatory bowel disease, whose disease was mildly active or was in clinical remission, had elicitable suppressor cell activity which fell within the normal range. In contrast, suppressor cell activity was markedly diminished or absent in seven patients with severe and active inflammatory bowel disease. These studies suggest that an alternation in Con A-stimulated suppressor cells exists in patients with active inflammatory bowel disease, which may contribute, in part, to the persistent inflammation in the gastrointestinal tract.