Twenty studies included biopsy-verified myocarditis with findings of immune infiltration of the myocardium with CD4-positive T-lymphocytes, CD8-positive T-lymphocytes and CD68-positive macrophages [11, 16, 19, 22, 23, 26, 36–39, 42, 43, 47, 50, 61, 62, 67, 71]. The gene discussed is CD4; the disease is myocarditis.