# Does the Organ Matter in PTLD Development in Solid Organ Transplant Recipients? A Multicenter Observational Study of Risk and Prognostic Factors

## TL;DR

This study shows that the type of transplanted organ affects the risk and timing of post-transplant lymphoproliferative disorder (PTLD) and patient survival.

## Contribution

The study provides organ-specific insights into PTLD risk and prognostic factors using a large multicenter registry.

## Key findings

- Kidney transplant recipients had a significantly longer median time to PTLD onset compared to liver and lung recipients.
- Older age at transplantation was linked to earlier PTLD development and worse survival in kidney recipients.
- Liver recipients treated with tacrolimus developed PTLD later than those treated with cyclosporin.

## Abstract

Post-transplantation lymphoproliferative disorder is considered one of the most life-threatening complications of solid organ transplantation (SOT). Evidence suggests that PTLD risk is influenced by organ graft type. Since only a limited population is at risk of PTLD, the majority of research has been based on either small cohorts of single graft-type recipients or larger cohorts of multiple types of SOT recipients. The conclusions from such studies may not be sufficiently generalizable or may miss organ-specific risk and prognostic factors. To address these limitations, we created a multicenter registry that included 103 PTLD patients diagnosed out of 9432 kidney, 3500 liver, and 331 lung transplant recipients. We used this registry to analyze various risk and prognostic factors according to organ graft types. We found that the constellation of factors affecting the time of PTLD onset and patient survival differs between kidney and liver transplant recipients.

Background/Objectives: The risk of post-transplantation lymphoproliferative disorder (PTLD) varies according to the type of transplanted organ. To investigate the factors contributing to PTLD development and treatment outcomes, we established a multicenter registry that included patients diagnosed with PTLD within a population of 13,263 kidney, liver, and lung transplant recipients (KTRs, LTRs, and LngTRs, respectively), observed in a period between 2000 and 2023. Methods: The chi-squared test was used to analyze differences in group composition. Univariate and multivariate Cox regression were applied to determine the impact of factors upon PTLD onset and patient survival. Results: Our registry included 58 out of 9432 KTRs, 40 out of 3500 LTRs, and 5 out of 331 LngTRs. The median time to PTLD onset was significantly longer among KTRs (117 months post-transplant) than among LTRs (49 months, p < 0.001) and LngTRs (5 months, p < 0.001). LTRs treated with tacrolimus developed PTLD later compared to LTRs treated with cyclosporin (p = 0.042). In multivariate analysis, older age at first transplantation correlated with earlier disease development in SOTRs (HR = 1.03, p = 0.006) and KTRs (HR = 1.04, p = 0.003). Older age at first transplantation was also associated with worse survival among KTRs (p = 0.045). Conclusions: 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.