P1704POST-TRANSPLANTATION LYPMHOPROLIFERATIVE DISORDER (PTLD) RISK AND PROGNOSTIC FACTORS IN KIDNEY AND LIVER TRANSPLANT RECIPIENTS
Authors: Staros Rafal , Foroncewicz Bartosz , Zieniewicz Krzysztof , Kosieradzki Maciej , Nazarewski Sławomir , Ziarkiewicz-Wróblewska Bogna , Joanna Raszeja-Wyszomirska , Jędrzejczak Anna , Pączek Leszek , Mucha Krzysztof 
Published: June 2020

Abstract

Background and Aims
Post-transplantation lymphoprolipherative disorder [PTLD] is a serious, potentially fatal complication of transplantation [Tx], pathogenesis of which remains to be fully understood. Due to the intrinsic difficulty of assembling a large cohort of rare disease patients, most research papers have investigated PTLD in the general graft recipient population. They report however, that the relative risk of disease development significantly varies in relation to the type of transplanted organ, with multiorgan and intestinal graft recipients possessing the highest risk (RR=239.5), liver (RR=29.9) and the lowest for kidney transplant recipients (RR=12.6).
The aim of this study was to investigate the factors contributing to the development, course, treatment and outcomes of PTLD and compare their impact on the populations of liver [LTR] and kidney [KTR] transplant recipients.

Method
In this retrospective cohort study we have included all KTRs and LTRs diagnosed with PTLD at our centres between 2002 and 2017. The following data were collected from the patients’ medical records: immunosuppression (IS), viral infections, PTLD type, treatment and outcomes. Mann-Whitney U-test was used to assess the differences in group composition, and the Log-rank test was used to compare Kaplan-Meier curves. Statistical analysis was performed in R version 3.2.3., p-values below .05 were considered statistically significant.

Results
We have identified 23 LTR and 16 KTR who matched our inclusion criteria. The mean age was 40.69 years. 61.5% of the patients were male, 38.5% female. Analysis of Kaplan-Meier curves revealed that PTLD occurred earlier in: LTRs (p&lt;.001); patients above the median age of 45 years at Tx (p=.002); patients whose IS regimens at the time of PTLD diagnosis contained tacrolimus [TAC] (p&lt;.001) or did not contain cyclosporin [CsA]. Among KTRs PTLD was diagnosed earlier in males (p&lt;0.05), patients over 45 years at Tx (p&lt;0.05), and those receiving TAC-containing IS regimens at PTLD diagnosis (p&lt;0.05). These factors were not statistically significant for LTRs, among whom PTLD development was affected by the presence of MMF in IS regimens at diagnosis (p&lt;0.05). Survival time was longer for patients receiving MMF-containing IS regimens (p&lt;0.05). LTRs were more likely than KTRs to achieve complete remission in response to treatment (p&lt;0.05).

Conclusion
Our results indicate, that in comparable KTR and LTR populations, the course of PLTD and response to treatment vary significantly. Factors such as patients’ age at transplantation, sex, type of maintenance IS have a different impact depending on graft type. In our opinion these findings, when applied to further research, could enhance our ability to identify patients at risk and potentially lead to the formation of more personalised guidelines to the diagnosis and treatment of PTLD.