Posttransplant lymphoproliferative disorders after renal transplantation in the United States in era of modern immunosuppression

Background. Posttransplant lymphoproliferative disorders (PTLD) still represent a major preoccupation after renal transplantation, even in the most recent years. Methods. We analyzed the incidence, risk, and prognostic factors of PTLD in a cohort of kidney recipients using the United States Renal Data System. Results. Among 25,127 Medicare patients transplanted between 1996 and 2000, 344 developed a PTLD defined as a non-Hodgkin lymphoma (1.4%). History of pretransplant malignancy (adjusted hazard ratio [AHR] = 3.54, CI 2.31-5.43), younger age (AHR = 1.91, CI 1.18-3.1), fewer HLA matches (AHR=1.32, CI 1.1-1.59) and treatment by ATG (AHR=1.55, CI 1.2-1.99) and OKT3 (AHR=1.37, CI 1-1.76), especially if given for rejection therapy were associated with an increased risk of PTLD. Mycophenolate and azathioprine were associated with a lower risk of PTLD (AHR=0.6, CI 0.47-0.78 and AHR=0.66, CI 0.46-0.95, respectively). IL2-receptor inhibitors and sirolimus did not modify the risk of PTLD. Patients without induction therapy treated with tacrolimus were at greater risk of lymphoma than those treated with new formulations of cyclosporine and those treated with antimetabolites (mycophenolate and azathioprine) have a lower risk of PTLD than those without. Patients with PTLD had poor survival (64% vs. 80% at 5 years). Older age, pretransplant malignancy and OKT3 were risk factors for death whereas treatment with mycophenolate was associated with a better survival (AHR=0.49, CI = 0.28-0.82). Conclusions. Our study highlights the contribution of patient history and immunosuppression in the risk of PTLD in the era of modern immunosuppression.