Clinical aspects on Epstein-Barr virus infection.

Epstein-Barr virus infection (EBV) was discovered 25 years ago in tumour cells from Burkitt's lymphoma. Extensive virological studies have relieved that EBV causes infectious mononucleosis and contributes to the pathogenesis of Burkitt's lymphoma and nasopharyngeal cancer. Atypical courses of the primary infection may induce meningoencephalitis or hepatitis and are attracting increasing attention. Antiviral treatment with acyclovir has been administered for 7 days, intravenously or orally, in the early stages of infectious mononucleosis, in 2 placebo controlled trials. An inhibition of oropharyngeal EBV replication was verified but minimal effects on clinical symptoms was observed. A combination of intravenous acyclovir and prednisolone treatment for 10 days was therefore tried in 15 patients with fulminant mononucleosis in a pilot study. A transient cessation of virus shedding was noticed in all patients, and a substantial clinical effect on pharyngeal symptoms and on fever was seen in 12/15 patients within 3 days. Treatment with chemotherapy or irradiation is recommended in EBV-associated B-cell lymphomas seen in immunosuppressed, transplanted, or human immunodeficiency virus-seropositive patients. No effect of acyclovir has been reported, but such therapy may be considered in the early stage when EBV induces a polyclonal B cell activation. Acyclovir treatment is effective in the EBV-genome positive hairy leukoplakia noticed in human immunodeficiency virus-seropositive patients. However, no effect of any antiviral therapy has been reported in the X-linked lymphoproliferative syndrome affecting in particular 2-7 year old boys. Prophylactic use of immunoglobulin or acyclovir has been suggested in susceptible children. These results indicate that the variety of clinical manifestations induced by EBV at least partly depend on the immune response elicited in the host and not of virus replication per se. Therefore, treatment of these various disorders cannot be generalized but must be based on the use of antiviral drugs combined with immunomodulatory agents.