الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Post-transplant lymphoproliferative disorders are a group of diseases that range from benign polyclonal to malignant monoclonal lymphoid proliferations. They arise secondary to treatment with immunosuppressive drugs given to prevent transplant rejection. Three main pathologic subsets/stages of evolution are recognized: early, polymorphic, and monomorphic lesions. The pathogenesis of Post-transplant lymphoproliferative disorders seems to be multifactorial.
Among possible infective etiologies, the role of EBV has been studied in depth, and the virus is thought to play a central role in driving the proliferation of EBV-infected B cells that leads to subsequent development of the lymphoproliferative disorder. It is apparent, however, that EBV is not solely responsible for the “neoplastic” state. Accumulated genetic alterations of oncogenes and tumor suppressor genes (deletions, mutations, rearrangements, and amplifications) and epigenetic changes (aberrant hypermethylation) that involve tumor suppressor genes are integral to the pathogenesis.
Antigenic stimulation also plays an evident role in the pathogenesis of Post-transplant lymphoproliferative disorders. Plasmacytoid dendritic cells that are critical to fight viral infections have been thought to play a pathogenically relevant role in Post-transplant lymphoproliferative disorders. Furthermore, regulatory T cells, which are modulators of immune reactions once incited, seem to have an important role in Post-transplant lymphoproliferative disorders where antigenic stimulation is key for the pathogenesis.
Post-transplantation lymphoproliferative disorders have emerged as important causes of morbidity and mortality in solid organ transplant recipients. Epstein-Barr virus plays a major pathophysiologic role in the development of many, if not most, of the highly diverse disease states, which span the spectrum from infection to malignancy, encompassed by the term “PTLD.” Clinical presentation and biological behavior associated with Post-transplantation lymphoproliferative disorders are highly variable; patients experiencing primary Epstein-Barr virus infection in the immediate post-transplantation period are most vulnerable. New insights into Post-transplantation lymphoproliferative disorders pathogenesis provide exciting opportunities for rational and targeted approaches to the diagnosis, prevention, and treatment of Post-transplantation lymphoproliferative disorders.