Post-Transplant Lymphoproliferative Disorder after Liver Transplant in the Pediatric Population: A Systematic Review

Background:

Post-transplant lymphoproliferative disease (PTLD), a group of lymphoid disorders ranging from indolent polyclonal proliferation to aggressive lymphomas is a known complication following solid organ transplantation. The aim is to study the characteristics, predictive factors, management, and outcomes of PTLD among pediatric groups after liver transplantation in particular.

Methods:

Following the PRISMA guideline, we performed a comprehensive literature search on PubMed, Cochrane Library, Embase, and clinicaltrials.gov from the past ten years on May 04, 2020. We used the MeSH terms of organ transplantation and lymphoproliferative disorders. Initial search revealed 1741 articles. We excluded all case reports, case series, pre-clinical trials, review articles, and meta-analysis. We found five retrospectives observational, one observational cohort study, and one multicenter cohort in the pediatric population. We extracted the data for baseline characteristics, the reason for transplantation, recipient & donor EBV status, immunosuppression used, type & stage of PTLD, organ system involved, duration between transplant and PTLD diagnosis, treatment, response to therapy, adverse effects of therapy and mortality.

Results:

We included seven retrospective observational studies with a total (n) number of 3116 post-liver transplant pediatric patients, out of which 135 (4.33%) patients who developed PTLD as a complication of transplantation were studied. The male to female ratio was 41: 55 with the gender of 6 patients unknown. In five studies, with 118 PTLD patients, 34 recipients and 24 donors were positive for EBV at the time of liver transplantation. In addition to EBV, CMV status of patients in 5 studies showed 11/25 (44%) PTLD patients positive for CMV at the time of transplant. Post-transplant immunosuppression was achieved among these seven cohorts with cyclosporine, tacrolimus, OKT3, mycophenolate mofetil, prednisone, and basiliximab. The diagnosis was made via biopsy, showing all histopathological types including early lesions 14/46 (30.4%), polymorphic 13/46 (28.3%), monomorphic 18/46 (39.1%), and classic Hodgkin's lymphoma PTLD 1/46 (2.1%). Diffuse large B-cell lymphoma was the most common subtype in 6/18 (33.3%) of samples with monomorphic PTLD. Hsu, et al. in their study showed a five-year survival rate of 33.3% for St. Jude's classification stage IV lymphoma compared to 88.9% for stage I-III. The median age for 36 patients from three studies at the diagnosis of PTLD was 39.6 months (range 24-48 months). The median duration from transplantation to the diagnosis of PTLD was 13.48 months (range 8-24 months) in 54 patients from four studies. PTLD treatment was achieved with a combination of reduction or withdrawal of the immunosuppressive drugs with antiviral prophylaxis, chemotherapy, irradiation & the use of monoclonal antibodies in a total of 57 PTLD patients for which post-transplant immunosuppression data was available. Study by Hsu, et al. reported that 5/16 (31.3%) patients had acute graft rejection and 2 had a chronic rejection in a group of 16 PTLD patients undergoing treatment for PTLD with a reduction in immunosuppressive therapy. The overall mortality in patients who developed PTLD was 15/54 (27.8%) in four of the studies.

Conclusions:

Pre-transplant EBV-naive status in patients was associated with a higher incidence of PTLD. Advanced stage (Stage IV) lymphoma was associated with poor survival outcomes. Monomorphic histopathology may be most commonly associated with PTLD post-liver transplant. The main approach for the treatment of PTLD is the reduction or complete withdrawal of immunosuppressive drugs, administration of antiviral drugs (ganciclovir/valganciclovir),and lymphoma treatment with chemotherapy or irradiation, and monoclonal antibody therapy such as rituximab. Management of PTLD with reduction or withdrawal of post-transplant immunosuppressive drugs in one cohort was associated with an increased risk of graft rejection. Thus immunosuppressive therapy maintaining a fine balance between the risk of graft rejection and risk of developing PTLD may be associated with better patient outcomes post-liver transplant.

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