Posttransplant lymphoproliferative disease: pathogenesis, monitoring, and therapy.

The spectrum of transplant-related lymphoproliferative diseases is expanding to include a variety of neoplasias that typically occur late after transplant including Epstein-Barr virus (EBV)-negative B- and T-cell lymphomas, EBV-positive T-cell lymphoma, myeloma, plasmacytoma, and Hodgkin's disease. New approaches to diagnosis and monitoring based on quantitative polymerase chain reaction for EBV DNA are being explored. What exactly is being measured (the source and character of the viral DNA) remains to be determined, as does the compartment that should be assayed (whole blood, serum, plasma, or lymphocytes). These questions not withstanding, there is an emerging consensus that these technologies will facilitate rapid diagnosis and therapeutic monitoring in the future. A myriad of therapeutic interventions are or will become available. Rituximab, alone or in addition to other therapies, promises a profound change in the landscape with regard to the treatment and perhaps the prevention of posttransplant lymphoproliferative disease. New approaches to adoptive cellular immunotherapy, including use of EBV-specific products from unrelated donors, nonspecifically activated autologous products, and genetically engineered T cells, are all being explored.