#3355 Differences in PTLD risk and prognostic factors between kidney and other solid organ transplant recipients, a multicenter observational study

Abstract Background and Aims Post-transplantation lymphoproliferative disorder (PTLD), a potentially fatal complication of transplantation, affects solid organ transplant recipients at different rates, depending on organ graft type: the risk is considered one of the lowest among kidney transplant recipients (KTRs), intermediate among liver transplant recipients (LTRs) and high for lung transplant recipients (LngTRs). In this study we aimed to investigate the factors affecting disease development and treatment outcomes of PTLD and compare their effect on KTRs, LTRs and LngTRs. Method To investigate the factors contributing to PTLD development and treatment outcomes, we created a multicenter registry which included KTRs, LTRs and LngTRs, diagnosed with PTLD. The data collected from medical records included: immunosuppression (IS), viral infections, PTLD type, treatment and outcomes. Chi-squared test was used to analyze the differences in group composition, and univariate Cox regression was applied to determine the impact of factors upon PTLD onset and patient survival. p-values below 0.05 were considered statistically significant. Results Our registry consisted of 58 KTRs, 40 LTRs, and 5 LngTRs from 6 transplantation centers in Poland. The groups significantly differed in IS treatment: triple-drug IS treatment, steroid (GCS) and cyclosporin (CsA) use was more frequent in KTRs (P < 0.001, P < 0.001 and P < 0.001 and respectively). In all groups Monomorphic B-cell PTLD was the most frequent. The median time from transplantation to PTLD onset was significantly longer among KTRs (117 months) than among LTRs (49 months, P < 0.001) and LngTRs (5 months, P < 0.001). Among KTRs, older age at first transplantation correlated with earlier disease development (P = 0.01). LTRs treated with tacrolimus developed PTLD later, compared to LTRs treated with cyclosporin (P = 0.042). CNIs did not significantly affect the development of the disease among KTRs. Reduced immunosuppression was associated with better survival among KTRs (HR = 0.34, P = 0.017). The LngTR group was too small for meaningful analysis. The overall survival at the end of observation period was 29% for KTRs, and was significantly lower than for LTRs and LngTRs (P = 0.003). Conclusion We identified clear differences in the factors affecting PTLD onset and survival between KTRs and LTRs. Organ-specific analyses are needed to improve our understanding of PTLD risk factors, treatment choices, and clinical outcomes.