Effect of cimetidine on T lymphocytes in a patient with giant benign gastric ulcer.

In view of the findings that Cimetidine, used in the treatment of gastric ulcers, blocks histamine-type 2 receptors, which are also present on T suppressor lymphocytes, a study was carried out in a 65-year-old male suffering from giant benign gastric ulcer and in parallel for control purposes in a healthy male of the same age. T suppressor cells obtained from peripheral blood of the patient were tested prior to institution of treatment with Cimetidine and 21, 62 and 100 days thereafter using 3 different tests - theophylline sensitivity, monoclonal antibodies OKT4 and OKT8 and as a functional test a local xenogeneic graft-versus-host reaction (GVHR). The number and percentage of T suppressor cells, which were high before treatment, showed a significant decrease after two months of treatment and this was paralleled by a decrease in suppressor activity and reversal of the functional activity of the T cells from negative to normal. Helper cells were normal before and after treatment. At the same time the patient showed a marked clinical improvement, with healing of the ulcer evidenced by endoscopy. It is suggested that Cimetidine may effect healing by influencing immune mechanisms.