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.