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.