ABCA1 and atherosclerosis: Leukocyte ABCA1 has not been previously considered to influence plasma HDL or RCT directly.[20], [23] Recent data, however, have suggested that cells other than macrophages influence tissue cholesterol removal (eg adipocytes).[24] Leukocyte ABCA1 is known to protect against atherosclerosis in animals [25], but our observations cannot distinguish between possible direct and indirect effects of leukocyte ABCA1 on lipid transport.