APOE and atherosclerosis: Interestingly, in contrast to increased atherosclerosis in MHCII−/− ApoE−/− double knockout mice (74), MHCII deficiency on B cells did not affect atherosclerosis in LDLR−/− mice despite large but incomplete reductions in MHCII in B cells (75); reductions resulted in reduced IgG1 and IgG2c but not IgG2b nor IgM.