This study found that immune deficiency results in increased neointimal formation (thickening of the artery wall) after arterial injury in mice. Adoptive transfer of B cells from wild type mice to immune deficient Rag-1 KO mice inhibited neointimal formation in the KO mice after arterial injury. The reconstituted KO mice showed increased presence of immunoglobulins like IgM and IgG in the injured arteries, similar to levels seen in injured arteries of wild type mice. This suggests that B cells and the antibodies they produce may play a role in limiting neointimal formation after arterial injury.