Th2 cells, especially in the acute phase of AD, produce certain cytokines such as Interleukin-4 (IL-4), Interleukin-13 (IL-13), and Interleukin-31 (IL-31), all of which have been identified as substantial contributors to the development and aggravation of AD (15–17). The gene discussed is IL4; the disease is Alzheimer disease.