The first experimental evidence that B cells impact atherosclerosis was provided by Caligiuri et al., who showed that splenectomy-induced acceleration of atherosclerosis in Apolipoprotein E deficient (Apoe–/–) mice could be rescued upon transfer of splenic B cells that were isolated either from wild type or Apoe–/– donors (46). The gene discussed is APOE; the disease is atherosclerosis.