We report an 18-year-old boy with common variable immunodeficiency who presented with splenomegaly as well as left axillary and lateral cervical lymphadenopathy. Main laboratory investigations showed severe thrombocytopenia. Epstein-Barr virus (EBV) DNA was detected in the patient's throat-washing specimens and lymph node biopsy. Lymphocytes from the lymph node biopsy were also positive for EBV nuclear antigen. Serology for EBV and cytomegalovirus was negative. A therapeutic attempt with acyclovir did not influence the course of infection. Six months' treatment with human lymphoblastoid interferon-alpha (IFN alfa) brought about the normalization of clinical and hematologic conditions. Detection on throat-washing specimens carried out 1 year after therapy was negative. Our preliminary experience suggests that human lymphoblastoid IFN-alpha is a valid alternative in therapy of immunodeficient EB virus-infected patients.