General Description The high affinity Immunoglobulin E receptor (FcεRI) is a tetrameric membrane protein complex (Fig. 1) expressed on mast cells and basophils (1), which belongs to the family of immunoreceptors involved in antigen recognition (2). It is composed of one α subunit containing one

General Description Besides the high affinity IgE receptor mast cells (MC) also express Fcγ receptors (FcγR) (1). However, other receptors for immunoglobulin isotypes such as FcaRI, FcdRI and Fca/mR are not found to be expressed on MC. FcγR exist in multiple isoforms categorized, either in