Studies in mice have shown that B cell accumulation occurs in the infarcted myocardium following myocardial infarction.139 Typically, B cells produce natural IgM antibodies against non-myosin heavy chain II, which can damage the heart because their response in generating specific antibodies is delayed.139 Furthermore, mature B lymphocytes selectively produced Ccl7 and induce the mobilization and recruitment of Ly6Chi monocyte to the heart after myocardial infarction, leading to decreased myocardial function.478 It’s important to note that not all B cells are harmful. The gene discussed is CCL7; the disease is myocardial infarction.