IL4 and Alzheimer disease: In another study, Lactobacillus acidophilus (L. acidophilus) KBL409 strain alleviated AD in mice, showing decreased skin keratinization and epidermal thickness, downregulated Th1 (interferon-γ), Th2 (IL-4, IL-5 IL-13), and Th17 (IL-17), and upregulated the expression of IL-10, an anti-inflammatory cytokine, and Foxp3, a regulator of immune system response [51].