Polyclonal proliferation of lymphocytes containing the epstein-barr virus genome in a patient dying of myocarditis in chronic active Epstein-Barr virus infection

An 11-year-old boy had intermittent fever and hepatosplenomegaly. The diagnosis of chronic active Epstein-Barr virus (EBV) infection was established from an abnormal pattern of anti-EBV antibody; EBV was detected in bone marrow cells. Immunochemotherapy alleviated the patient's symptoms. However, when a subsequent oral prednisolone dose was tapered, heart failure ensued and he died. Autopsy findings demonstrated that myocarditis resulted from infiltrating T lymphocytes with the EBV genome and a benign histologic appearance. A clonality study of T lymphocytes indicated no such evidence of monoclonality. EBV-infected T cells play an important role in the pathogenesis of myocarditis in chronic active EBV infection.