PRF1 and Alzheimer disease: Up to 90% of patients with AD have S.a. colonization which correlates with AD severity, contributes to various pathophysiological factors such as skin barrier dysfunction through protease activity, downregulation of terminal differentiation markers in the skin, and production of virulence factors such as cytolysins, protein A, and S.a. superantigens, with upregulation of Th2 cytokines [5,16,38].