However, Th17 cells are also involved in the pathogenesis of autoimmune and allergic diseases.[39–41] Similarly, immunosuppressive CD4+CD25+ Foxp3+Treg cells exert important effects on the maintenance of immune homeostasis and immune tolerance by producing antiinflammatory cytokines, which can inhibit both Th1 and Th2 responses.[39–41] Moreover, our finding of the association of AD with multiple autoimmune diseases implies that early-life environmental and immunogenetic factors may have generalized effects on the development of both AD and autoimmune disorders. This evidence concerns the gene CD4 and Alzheimer disease.