IMMUNOSUPPRESSION IN THE TREATMENT OF INFLAMMATORY BOWEL DISEASE.

Lymphoid sub populations in the blood and rectal mucosa were studied in six patients with ulcerative colitis or Cohn's disease who had been treated for over three year with azathioprine. Serial assays were performed to observe the changes occurring up to 12 weeks after treatment with azathioprine was stooped. While the patients were on the drug tow lymphoid populations showed marked depression. These were the plasma cells of the rectal lamina procris, and blood lymphocytes with cytotoxic activity against antibody-sensitized tared cells ('k' cells). After stopping azathioprine, both population showed a rapid rise to reach near normal levels by 12 weeks, Most of the recovery occurred within 3-5 weeks. There was no significant change in circulating immunogolblin-staining cells which could be attributed to the drug. Nor was azathioprine shown to have any effect on the mitotic response of lymphocytes to phytohaemagglutinin. Three patients, however, gave very low or erratic responses to PHA, which may have been related either to their disease or to steroid therapy, These results are discussed in relation to the mode of action of purine analogues as immunosuppressive agents. [ABSTRACT FROM AUTHOR]