The autologous epidermal S. hominis A9 strain isolated from the skin of healthy people can secrete antimicrobial peptides (lantibiotics) to directly kill S. aureus, and produce autologous induced peptides (AIP) to inhibit the quorum sensing system of S. aureus, reduce the expression of toxins (such as PSMα), and alleviate the symptoms of AD (101). The gene discussed is FOLH1; the disease is Alzheimer disease.