Allergy-Associated Polymorphisms of the FcεRIβ Subunit Do Not Impact Its Two Amplification Functions

Abstract

Two variants of the β-chain of the high affinity IgE receptor FcεRI, I181L-V183L and E237G, have been found associated with allergy. We have previously shown that the β-chain plays at least two distinct amplifier functions. It amplifies FcεRI surface expression and signaling, resulting in an estimated 12- to 30-fold amplification of downstream events. To test the hypothesis that the I181L-V183L and E237G β variants may be functionally relevant and could directly contribute to an allergic phenotype, we have evaluated the functional impact of the β variants on the two amplifier functions of β. We found that these variants have no direct effect on the β amplifier functions. However, the possibility remains that these variants are in linkage disequilibrium with other more relevant polymorphisms or are affecting unknown β-chain functions.