In this multi-ethnic, cross-sectional epidemiological study, we have demonstrated that a) chronic adaptive immune activation, as reflected by higher circulating CD4+ memory cells and lower circulating CD4+ naive cells, is associated with the degree of subclinical atherosclerosis; b) CMV and H. pylori serological titers were identified as the main predictors of memory and naive subpopulations, suggesting a potential role of these pathogens in chronic immune activation and inflammation, and through these pathways, chronic diseases such as atherosclerosis. This evidence concerns the gene CD4 and atherosclerosis.