Posttransplant lymphoproliferative disorders

In 1968, Starzl reported the clinical observation that transplant patients are prone to develop lymphomatous growths (1). The term posttransplant lymphoproliferative disorder (PTLD) is applied to a group of lymphoproliferative disorders arising in a pharmacologically immunocompromised host after solid-organ or allogeneic stem cell transplantation. Among iatrogenic immune deficiency states, PTLD is quite common (2). PTLDs are the most serious complications of chronic immunosuppression and represent one of the most commonly observed fatal consequences of immunosuppression in patients undergoing solid-organ transplantation. PTLDs are the most common malignancy complicating organ transplantation after nonmelanomatous skin cancer and in situ cervical cancer (3). PTLDs represent 21% of all malignancies versus 5% of malignancies in immunocompetent patients (not sure what this means?). Clinically, this group of disorders might be slow growing or aggressive, localized or mulitcentric, associated with symptoms or no symptoms, more characteristically involve extranodal sites, and disease in the allograft organ is more common (4-6). The biology, diagnosis, and management of this heterogeneous group of disorders have nuances that are different than other non-Hodgkin's lymphomas. The issues in evaluating published PTLD data involve multiple variables, including Epstein-Barr virus (EBV) serostatus prior to the organ transplant in the donor and the recipient, stages of disease, types and doses of immunosuppressive agents utilized in the course of the transplant, initial PTLD management strategies (surgery, immunosuppression reduction strategies), types of treatment (rituximab as monotherapy, etc.), the timing and incorporation of treatment regimens, the timing of treatment after the PTLD diagnosis, presentation from the time of transplant, pathology reporting, locations of extranodal involvement, and comorbid conditions [other vital organ involvement, performance status, active infections (Cytomegalovirus (CMV), fungal), etc. Two International Consensus Development meetings were held in 1997 and 1998 that addressed different issues in PTLD in working groups, recommended management guidelines, and set the stage for future directions (7). This review will focus on adult solid-organ PTLD.