Treatment of EBV-induced lymphoproliferative disorder with epipodophyllotoxin VP16-213

Epstein-Barr virus-recent advances

Epstein-Barr virus is a tumorigenic herpes virus that is ubiquitous in the adult population. The virus is generally spread to and between young children through salivary contact, and only causes clinical illness where primary infection is delayed until adolescence or beyond, when an intense immunopathological reaction leads to the symptoms of infectious mononucleosis in roughly 50% of cases. More than 90% of the world's population carry Epstein-Barr virus as a life-long, latent infection of B lymphocytes. Recent data show that by mimicking B-cell antigen-activation pathways the virus enters the long-lived memory B lymphocyte pool where it evades immune elimination by severely restricting its own gene expression. By influencing B-cell survival mechanisms Epstein-Barr virus may induce tumours such as B lymphoproliferative disease and Hodgkin's disease. Vaccines are being developed to prevent and/or treat these conditions, but an animal model is required to study pathogenesis before a rational vaccine strategy can be formulated.

Allogeneic bone marrow transplantation for active Epstein-Barr virus-related lymphoproliferative disease and hemophagocytic lymphohistiocytosis in an infant with severe combined immunodeficiency syndrome

A 5-month-old male presented with fever, hepatosplenomegaly, leukocytosis with atypical lymphoblasts, anemia and thrombocytopenia. Severe combined imunodeficiency syndrome (T-, B+, NK+), B lymphoproliferative disease and hemophagocytic lymphohistiocytosis triggered by Epstein-Barr virus (EBV) were diagnosed. As his clinical situation deteriorated rapidly, BMT was performed with unmanipulated marrow stem cells from his EBV-positive HLA-identical sister after conditioning with dexamethasone (1.75 mg/kg/day), cyclophosphamide (114 mg/kg) and etoposide (10 mg/kg), with no immunosuppression given post transplant. Engraftment occurred on day 6 with explosive proliferation of donor CD8(+) T cells. The patient died 3 days later from acute respiratory distress syndrome. Autopsy revealed full donor engraftment and no signs of hemophagocytic lymphohistiocytosis or B lymphoproliferative disease. Thus, transplanted T cells can expand very rapidly within days after BMT and clear EBV lymphoproliferative disease and hemophagocytic lymphohistiocytosis.