Haruki Komagoe

Allergen- and Anti-IgE-Induced Histamine Release from Whole Blood

The release of histamine by allergen and anti-IgE from whole blood was observed in 34 asthmatic subjects with a positive skin test to house dust. The time course of histamine release showed that the release by allergen and anti-IgE peaked after 15 min incubation. There was no significant difference in the time course of the release from whole blood between allergen and anti-IgE. Anti-IgE-induced histamine release correlated to a certain extent with the serum IgE level. Histamine release by house dust, on the other hand, correlated with the radioallergosorbent test score. A striking difference was present in the dose-response slope between allergen and anti-IgE. The maximum percent release correlated with the dose-response slope by allergen, but not by anti-IgE. The amount of histamine release induced by anti-IgE paralleled the amount of the release by house dust in the cases sensitive to the allergen; less sensitive basophils to anti-IgE were less sensitive to house dust.

Decrease in reactivity of basophils by immunotherapy with housedust extract

Changes of basophil reactivity to housedust extract and anti‐IgE during immunotherapy was examined in thirteen patients with bronchial asthma sensitive to housedust. (i) A significant decrease in the morphological reactivity of basophils to housedust extract was observed 6 months after the beginning of immunotherapy with the antigen, and a significant decrease after 12 and 18 months’ therapy, accompanied with the decrease of histamine release from the cells. The percent reactive basophils to the antigen decreased from 59.2 ± 2.9% before the therapy to 40.0 ± 1.8% after 18 months’immunotherapy. (ii) A decrease in the morphological reactivity of basophils to anti‐IgE was also shown during immunotherapy. The basophil reactivity to anti‐IgE decreased significantly at the late stage (18 months) of immunotherapy. (iii) A significant reduction of specific IgE antibody to housedust was observed 12 and 18 months after the beginning of immunotherapy. It was suggested from these results that immunotherapy causes some changes on the surface of basophils and decreased reactivity of the cells, and that a decrease of reactive basophils to anti‐IgE in the process of immunotherapy might be due to a decrease in number of IgE receptors essentially or functionally.