Reduced atherosclerosis in Apoe–/–Nhe1+/– mice (Fig. 2) and localization of pHrodo signals, IgE immunoreactivity, and TUNEL-reactivity to areas rich in macrophages in atherosclerotic lesions (Fig. 3a, d, g) support a role of IgE-mediated macrophage Nhe1 activation in atherosclerosis. This evidence concerns the gene APOE and atherosclerosis.