<b>Context:</b> Cluster of differentiation 40 (CD40), and its ligand CD40L, are major co-stimulatory molecules whose interactions are important in both cellular and humoral immunity, and has been suggested to play a role in the pathogenesis of acute coronary syndrome.
CD40/CD40L may participate in the development of coronary atherosclerosis and the triggering of acute coronary syndromes, while sCD40L seems to have a prognostic role not only in subjects with advanced atherosclerosis but also in the general population.