Immunodeficient patients are at higher risk for developing lymphoproliferative disorders (LPDs), above all non-Hodgkin lymphomas (NHLs). Even though the association between primary immunodeiciency diseases (i.e. X-linked lymphoproliferative syndrome, common variable immunodeiciency, ataxia telangiectasia, and Wiskott-Aldrich syndrome) and LPDs, on the one hand, and between LPDs and autoimmune diseases, on the other, is well known, the leading causes of immunosuppression are, at present, organ transplantation and human immunodeiciency virus (HIV) infection. Lymphomas in the immunocompromised host have been traditionally regarded as having a more aggressive course, including extranodal involvement, a more rapid clinical course, poorer response to conventional therapies, and poorer outcome, but this has been called into question both in post-transplant lymphoproliferative disorders (PTLD) following solid organ transplant (SOT) and HIV-related lymphoma by more recent publications.
Tumors following solid organ transplantation (PTLD)
PTLDs are well recognized and potentially life-threatening complications after SOT. PTLD is seen in up to 10% of all SOT recipients. It is the most common form of post-transplant malignancy in children and in adults it is the second most common malignancy after skin cancer. In both children and adults it is the most common cause of cancer-related mortality after SOT, with the reported overall mortality for PTLD exceeding 50%. Up to 85% of PTLDs are of B-cell lineage and most of these (over 80%) are associated with Epstein-Barr virus (EBV) infection. Around 10-15% of PTLDs are of T-cell lineage, around 30% of which are associated with EBV.