Abstract: | A 6-year-old boy suffered from a severe lymphadenopathy, characterized histologically by a fulminant polyclonal immunoblast proliferation simulating malignant lymphoma with many immunoblasts resembling Reed-Sternberg cells. He had no history of infectious mononucleosis but Epstein-Barr virus (EBV) infection was evident from serological findings, and EBV-associated nuclear antigen (EBNA) was demonstrated in a high percentage of lymphocytes of blood and lymph nodes. An adequate humoral response to EBV ruled out the possibility of an X-linked recessive lymphoproliferative syndrome as the underlying cause of chronic EBV infection. A chromosomal defect in a subpopulation of lymphocytes was induced by interferon and might somehow be associated with a subtle immunodeficiency of our patient. After exacerbation of the disease chemotherapy was included in the treatment but the patient died 9 months after the onset of the disease. At autopsy the lymphoblastic cell proliferation had changed from that of immunoblasts to cells resembling the Burkitt's lymphoma cells. A change of the proliferating cell type was supported by means of cytochemical and immunological cell markers. The presence of EBV in these cells was demonstrated with the EBNA technique. It is concluded that our case may well support the hypothesis, that EBV may induce lymphoma-like polyclonal immunoblast proliferation in immunodeficient individuals, and that occasionally a monoclonal proliferation of the Burkitt's lymphoma type may supervene. |