Receptor Affinity IgG specificity Cell distribution FcγRI High IgG1, IgG3, IgG4 Induced by interferon‐γ on monocytes, neutrophils, macrophages, dendritic cell subpopulations; mast cells FcγRIIa Low IgG1, IgG3, but IgG2 binding limited to the FcγRIIa‐H131 form, ~70% people) All leukocytes and platelets except T and B lymphocytes FcγRIIc a Low IgG1, IgG3, IgG4 NK cells FcγRIIIa Low IgG1, IgG3. NK cells, macrophages, subpopulation of circulating monocytes, myeloid dendritic cells, neutrophils at very low levels Binding avidity reduced by Phe at position 158 FcγRIIIb Low IgG1, IgG3 Neutrophils FcγRIIb Low IgG1, IgG3, IgG4 B lymphocytes, some monocytes (can be upregulated); basophils; eosinophils? Plasmacytoid and myeloid dendritic cells; NK cells only of individuals with FcγRIIIb gene copy number variation Airway smooth muscle, LSEC, placenta, follicular dendritic cell