IGHE and Alzheimer disease: Notably, STAT6 protein plays a central regulatory role in this signaling pathway, which not only upregulates the expression of the Th2-specific transcription factor GATA3 and regulates T cell proliferation and Th2 cell differentiation, but also promotes the conversion of immunoglobulin classes to IgE and IgG1 in B cells (59), which correlates with the fact that multiple STAT6 polymorphisms are associated with high levels of IgE and an increased AD susceptibility is closely associated with increased susceptibility (60).