Refining the Role of B Cells in Atherosclerosis

Lymphocytes and plasma cells have long been detected in the plaque and adventitia of atherosclerotic human arteries,1 yet their role in regulating atherosclerosis has only recently begun to emerge.2–6 Two important studies published in 2002 provide evidence for an atheroprotective role for B cells.3,4 More recently, 2 groups broadened our understanding of B cells and atherosclerosis by providing evidence that B cells can also promote atherosclerosis. Treating atheroscle-rosis-prone mice with an anti-CD20 monoclonal antibody that depleted mature B2, but not B1a cells, attenuated atherosclerosis.5,6 This B2 cell depletion was associated with decreased activated splenic CD4+ T cells, T-cell proliferation, and lesional T cells, suggesting that B2 cells aggravate atherosclerosis through a T-cell–dependent mechanism. Further evidence for an atherogenic role for B2 cells was provided by studies by Kyaw et al6 who found aggravated atherosclerosis in lymphocyte-deficient apolipoprotein E −/− recombination activating gene 2 −/− common cytokine receptor γ chain-deficient or to B-cell–deficient atherogenic mice after adoptive transfer of 5×106 B2, but not B1, B cells.See accompanying article on page 1573 Sage et al7 present another important study on the impact of loss of B2 cells on atherosclerosis by …