Post-transplant lymphoproliferative disorder
It is an uncommon condition occurring in 0.2% of patients within one year of transplant, with an annual incidence of 0.04% thereafter. The risk of developing the disease is higher in children and recipients of small bowel transplants.
The disease is an uncontrolled proliferation of B cell lymphocytes following infection with Epstein-Barr virus.<ref name="pmid15660500">Gottschalk S, Rooney CM, Heslop HE (2005). "Post-transplant lymphoproliferative disorders". Annu. Rev. Med. 56: 29–44. doi:10.1146/annurev.med.56.082103.104727. PMID 15660500. http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.med.56.082103.104727?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dncbi.nlm.nih.gov. </ref> Production of an interleukin-10, an endogenous anti-T cell cytokine, has also been implicated.
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,<ref name="urlHematopathology">"Hematopathology". http://library.med.utah.edu/WebPath/HEMEHTML/HEME099.html. </ref> 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.