These discrepancies could be explained by lack of control littermates, as well as CD19-Cre toxicity and lack of penetrance.65 Thus, future experiments using the more efficient Mb1Cre/+ system66 and targeting MHCII in different B-cell subsets should shed light on the role of B-cell antigen presentation in atherosclerosis. The gene discussed is CD19; the disease is atherosclerosis.