This is thought to be due to the capacity of IgG and IgE to form immune complexes that cross-link activator Fc receptors and trigger vascular inflammation.14–16 Despite being overall proatherogenic,17,18 IgG autoantibodies to particular self-antigens may also have atheroprotective properties19 as is the case for anti-malondialdehyde-LDL IgG raised through vaccination.20 On the other hand, natural IgM antibodies coming from B1 cells,7 and T cell–dependent extrafollicular21,22 IgM antibodies23,24 coming from MZB cells9,25 protect from atherosclerosis. This evidence concerns the gene CD40LG and atherosclerosis.