Cd8(+) T-lymphocytes infiltrate the myocardium in fulminant herpes virus myocarditis

We report two cases of fulminant viral myocarditis in previously healthy ch ildren. They were caused by herpes simplex virus (HSV)-1 (in a boy aged 3 y ears) and Epstein-Barr virus (EBV) (in a boy aged 12 months). We obtained t he diagnosis of HSV-1 myocarditis by immunohistochemistry and the diagnosis of EBV myocarditis by in situ hybridization. Histologic examination of hea rt tissue from the two boys revealed mononuclear cell infiltration of the m yocardium. Immunohistochemical staining identified these cells as CD8(+) T- lymphocytes. CD8(+) T-lymphocytes induced by herpes virus infections may pl ay an important role in the damage to heart muscle fibers seen in fulminant myocarditis in previously healthy children. To our knowledge, this is the first report of HSV-1 or EBV myocarditis (at least in children) in which vi ral infection has been demonstrated in the myocardium.