APOE and Alzheimer disease: Carter et al. state that AD susceptibility genes like APOE, apolipoprotein A1 (APOA1), clusterin, alpha 2-macroglobulin, insulysin, and caspase-3 adhere to HSV1 and viral binding complement components, C3 and complement receptor-1 (CR1), which are involved in the clearance/degradation of amyloid-β [43].