The pattern of estrogen and estrogen receptor involvement in the immune response of allergic diseases with known expression of estrogen receptors by each immune cell type: antigen presentation, Th2 polarization, isotype switching, mast cell degranulation and the effect stage. Abbreviations: E2: estrogen; ER: estrogen receptor α or estrogen receptor β; IgE: immunoglobulin E; IgG1: immunoglobulin G1; IgG2b: immunoglobulin G2b; Ag: antigen; MDP: macrophage and dendritic cell progenitor cell; DC: dendritic cell; Mac: macrophage; N-CD4+ T: native CD4+ T cell; Gray arrow represents enhancement of estrogen; White arrow represents inhibition of estrogen; F: female; M: male.