Suppressor T cell numbers and function in atopic patients with high serum IgE levels

Suppressor T cell function and the sensitivity of lymphocyte transformation to histamine has been studied in 9 atopic patients with high serum IgE levels and in 14 controls. The effect of concanavalin A (Con A) induced suppressor T cells on the proliferative response of fresh lymphocytes to mitogens and antigens was measured; in atopic subjects the median suppression to 5.0 micrograms/ml Con A was 80% to 1.0 microgram/ml Phytohaemagglutinin (PHA) was 73%, to Dermatophagoides pteronyssinus extract was 45% and to streptokinase--streptodornase was 24%. Indomethacin increased lymphocyte proliferation to mitogens, but to a variable degree, in both groups. Histamine suppressed lymphocyte transformation to PHA and Con A (median suppression in normal subjects 38 and 46%, and in atopics 51 and 60%) and to D. Pteronyssinus extract. There was no significant difference between normal subjects and atopics in any of these functional assays. The relative and absolute numbers of total T cells, helper T cells and suppressor T cells measured by monoclonal antibodies and the helper to suppressor T cell ratio were normal in the atopic group. These results show that the activity of Con A induced suppressor T cells and the effect of histamine and indomethacin on lymphocyte proliferation is normal in highly atopic subjects. No suppressor T cell defect has been identified using these assays.