We previously reported the pathogenic roles of Hcy-induced B-cell activation and antibody production, especially pathological anti-β2GPI IgG, in atherosclerosis and abdominal aortic aneurysm in humans and mice.16,18 In the present study, HHcy treatment significantly increased the levels of total IgG and anti-β2GPI IgG in plasma and kidney homogenates of sham and 2K1C mice (Fig. 1e–h). This evidence concerns the gene APOH and abdominal aortic aneurysm.