In support of this idea, growing population-based studies found an inverse (and independent from HDL-C plasma concentration) association between “protective” HDL accessory proteins (in particular PON1 and Lp-PLA2) and the risk of AD; at the opposite, the levels of prooxidant and proinflammatory MPO and SAA have been often found to be higher in AD compared with healthy controls. This evidence concerns the gene PON1 and Alzheimer disease.