Persistent Epstein-Barr virus infection in a child with hypergammaglobulinaemia and immunoblastic proliferation associated with a selective defect in immune interferon secretion.

A 5-year-old girl had a chronic disease characterised by fever, lymphoid hyperplasia, interstitial pneumonitis, thrombocytopenia, and polyclonal hypergammaglobulinaemia. Evidence for severe, persistent Epstein-Barr virus (E.B.V.) infection was found: titres of antibody to E.B.V. viral capsid antigen (IgM and IgG) and early antigen were extremely high, cells containing E.B.V.-associated nuclear antigen (E.B.N.A.) were found in lymph nodes and blood, and spontaneous permanent lymphoblastoid cell lines were established from both sources over a period of a year. After exacerbation of the polyclonal proliferation of immunoblasts the patient died 19 months after the onset of the disease. No defect in humoral or cellular immunity was detected, except for a selective defect in immune interferon secretion by peripheral mononuclear cells. Our results suggest an important role for immune interferon in host defence against E.B.V. infection and in the regulation of immune responses.