IgE-receptor antibody

Antibodies directed against the alpha chain (30 kDa; chromosome 1q23.2) of the high-affinity IgE receptor (Fc epsilon RI alpha) expressed on dermal mast cells and basophilic leukocytes. The IgE receptors consist of a complex of a gamma 1, gamma 2 , alpha and beta chain. The alpha chain contains two domains alpha 1 and alpha 2 . In about 25 % of cases, the antibodies are directed against the IgE binding site of the receptor. In the remaining 75 %, the antibodies react with epitopes located outside the IgE binding site.

Histamine release by the autoantibodies occurs after cross-linking of adjacent receptors by the antibodies bound to the alpha chain. After cross-linking of the receptor, intracellular activation of the protein thyrosine kinase LYN and DYC by the gamma 1 and gamma 2 chains occurs, which in turn activate protein kinase C and initiate the elimination of histamine. Whether the antibodies trigger an activation of the complement system is still debatable.

1. Oettgen HC et al (2015) IgE receptor signaling in food allergy pathogenesis. Curr Opin Immunol 36:109-114.