CD40LG and atherosclerosis: MZB cells play a role in limiting the development of atherosclerosis through interactions with T follicular helper cells6 and through their production of atheroprotective anti-OSE IgM antibodies.5,7 Mice with a selective deletion of MZB cells have accelerated the development of atherosclerotic lesions.5 This suggests that transient inhibition/depletion of MZB cells is required post-MI and highlights the importance of assessing atherosclerosis progression in patients treated with B2 cell–depleting therapies.