Biomolecular regulation of the IgE immune response

Several cell types, including mast cells, basophils, macrophages/monocytes, lymphocytes, platelets and eosinophils, may bind or contain IgE. To investigate the source of cell-associated IgE and its relation to spontaneous IgE synthesis, peripheral blood mononuclear cells from allergic and non-allergic donors were examined. Using a combination of different cell fractionation techniques and varying methods for extraction of cell-associated IgE, data were obtained indicating that monocytes constitute a major source of cell-associated IgE in human blood. The amount of cell-associated IgE in peripheral blood mononuclear cells from allergic and non-allergic donors varied more than 100-fold but correlated closely to the level of serum IgE (r = 0.84, p < 0.001, n = 38). Spontaneous and mitogen-induced in vitro syntheses of IgA, IgE and IgG were compared for allergic and non-allergic donors. Only one donor with very high serum IgE demonstrated spontaneous or mitogen-induced in vitro IgE synthesis despite synthesis of IgA and IgG.