Nonspecific suppressor cell function in atopic subjects.

The status of concanavalin A (Con A)--nonspecific suppressor cell function and histamine-receptor--carrying mononuclear cells in 19 allergic and 27 nonallergic individuals was investigated. No differences were detected between the two groups with respect to suppression by Con A--activated suppressor cells of polyvalent Ig biosynthesis, IgG secretion, or mitogen-induced proliferative responses. Histamine-receptor--carrying cells of the allergic subjects were numerically equal to those of the nonallergic subjects. Mononuclear cells from the allergic group, however, required a higher dose of histamine than did those for the nonallergic group to induce suppression in vitro (p less than 0.02 for 10(-4) M histamine and p less than 0.05 for 10(-3) M histamine). Plasma from the allergic group contained higher levels of histamine activity (p less than 0.05). Plasma from either allergic or normal groups did not affect histamine activity in vitro. There are no apparent functional abnormalities of antigen-nonspecific mononuclear cells in the allergic patients with respect to non--IgE-mediated in vitro parameters. The demonstrated dysfunction of histamine-receptor--carrying cells could be attributed to high levels of circulating histamine that could result in receptor modulation in vivo. More work is needed to clarify the status of antigen-nonspecific and antigen-specific suppressor cells that regulate IgE biosynthesis in allergic states.