However, rIL-13 signaling directly to macrophages ameliorates the infiltration of CD4 and CD8 T cells in the myocardium after MI, and exacerbated frequencies of CD4 and CD8 T cells in the myocardium of rIL-13–treated IL-4RαMacKO mice correlate with scar aggravation after MI. The gene discussed is CD4; the disease is myocardial infarction.