Accumulation of foam cells — macrophages with intracellular lipid droplets — in arterial walls is a hallmark of atherosclerosis. Bernelot Moens and colleagues report increases in circulating monocytes with intracellular lipid accumulation, associated CCR2 expression, and enhanced monocyte migration in patients with familial hypercholesterolaemia. These changes could be reversed by PCSK9-inhibitor treatment.