Modulation of suppressor-cell activity by cimetidine in patients with common variable hypogammaglobulinemia.

Because of evidence of a possible immunoregulatory role for cimetidine, an antagonist to histamine H2 receptors, we studied the effects of this drug in five adult patients with common variable hypogammaglobulinemia. Three patients had excessive suppressor-cell function associated with panhypogammaglobulinemia, whereas the other two had no apparent T-cell defects. The patients were given a one-month course of oral cimetidine (1200 mg daily in four divided doses). Subsequently, the three patients with excessive suppressor-cell function had a marked reduction in suppressor activity along with a decrease in the number of suppressor cells (T8+). One of these three had a marked rise in both in vitro immunoglobulin secretion and serum immunoglobulin concentrations, which was reversible after the drug was stopped for three months and reproducible when therapy with cimetidine was repeated. There was no difference in immunoglobulin secretion or suppressor-cell activity while taking cimetidine between the two patients with common variable hypogammaglobulinemia without excessive suppressor-cell activity and control patients with duodenal ulcers. The data suggest that H2-receptor antagonists may decrease excessive suppressor-cell activity and allow endogenous immunoglobulin production in some patients with common variable hypogammaglobulinemia.