We previously reported that ORAIP-expressing CD4+, CD8+, or CD14+ cells infiltrated the atherosclerotic arterial tissues of patients with heterozygous familial hypercholesterolemia, suggesting a possibility that infiltrating immune cells (such as T-cells and macrophages) induce apoptosis of the arterial smooth muscle cells by secreting ORAIP [27]. This evidence concerns the gene CD4 and familial hypercholesterolemia.