Suppression of T lymphocyte mitogen response in patients with mastocytosis.

Immunological functions were studied in 22 patients with mastocytosis. Lymphocyte stimulation with concanavalin A (Con A) and phytohemagglutinin showed that the patients responded with lower mitogenic activity than healthy controls. Furthermore, the lymphocytes of patients with the most extensive mast cell disease had a significantly lower Con A mitogen response than the lymphocytes of the rest of the patients. The effect of histamine and its specific metabolites, tele-methylhistamine and tele-methylimidazoleacetic acid (MeImAA), on the Con A lymphocyte mitogen response was also studied in healthy controls. Histamine had a clear suppressive effect, while the metabolite tele-methylhistamine caused only slight inhibition and MeImAA apparently had no effect. The total T cell, suppressor and helper cell numbers, measured with monoclonal antibodies, and the amount of immunoglobulins in serum were found to be normal.