POSTN and Alzheimer disease: AD patients with colonized skin by S. aureus have increased disease severity, elevated eosinophil blood counts, total IgE serum levels, CCL17 and periostin (Th2 biomarkers) plasma levels, and suppressed activity of Treg cells [72] when compared with those without S. aureus colonization [73], corroborating the chronic immune activation described in AD.