Post-transplant lymphoproliferative disorder
|Post-transplant lymphoproliferative disorder|
|Classification and external resources|
Post-transplant lymphoproliferative disorder (PTLD) is the name given to a B-cell proliferation due to therapeutic immunosuppression after organ transplantation. These patients may develop infectious mononucleosis-like lesions or polyclonal polymorphic B-cell hyperplasia. Some of these B-cells may undergo mutations which will render them malignant, giving rise to a lymphoma.
In some patients, the malignant cell clone can become the dominant proliferating cell type, leading to frank lymphoma, a group of B cell lymphomas occurring in immunosuppressed patients following organ transplant.
The disease is an uncontrolled proliferation of B cell lymphocytes latently infected with Epstein-Barr virus. Production of an interleukin-10, an endogenous, pro-regulatory cytokine, has also been implicated.
In immunocompetent patients, Epstein-Barr virus can cause infectious mononucleosis in adolescent, which is otherwise asymptomatic in children during their childhood. However in immunosuppressed transplant patients, the lack of T-cell immunosurveillance can lead to the proliferation of these EBV-infected of B-lymphocytes.
Depletion of T cells by use of anti-T cell antibodies in the prevention or treatment of transplant rejection further increases the risk of developing post-transplant lymphoproliferative disorder. Such antibodies include ATG, ALG and OKT3.
Polyclonal PTLD may form tumor masses and present with symptoms due to a mass effect, e.g. symptoms of bowel obstruction. Monoclonal forms of PTLD tend to form a disseminated malignant lymphoma.
PTLD may spontaneously regress on reduction or cessation of immunosuppressant medication, and can also be treated with addition of anti-viral therapy. In some cases it will progress to non-Hodgkin's lymphoma and may be fatal. A phase 2 study of adoptively transferred EBV-specific T cells demonstrated high efficacy with minimal toxicity.
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- Nourse, JP; Jones K; Gandhi MK. (May 2011). "Epstein-Barr Virus-related post-transplant lymphoproliferative disorders: pathogenetic insights for targeted therapy.". Am J Transplant 11 (5): 888–95. doi:10.1111/j.1600-6143.2011.03499.x. PMID 21521464.
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