MONOMORPHIC POST-TRANSPLATATION LYMPHOPROLIFERATIVE DISORDERS AFTER SOLID ORGAN TRANSPLANTATION – SINGLE INSTITUTE EXPERIENCE

Abstract

Introduction: Solid organ transplantation (SOT) is an effective treatment modality for children and young adults with end-stage organ failure with 5-year overall survival ranging from 25 to 95% depending on the transplanted organ. Patients subsequently require lifelong immunossupression to maintain graft health and limit the risk of graft rejection. Commonly used immunosuppressants to inhibit organ recipient T-lymphocyte function include calcineurin inhibitors (CNI), mTOR inhibitors, thiopurines, and antimetabolites. Most cases of monomorphic Post-Transplantation Lymphoproliferative Disorders (m-PTLD) are related to the Epstein Barr virus (EBV) and occur in patients who were EBV seronegative before the transplant. Objective: Our aim is to assess the overall survival in patients diagnosed with monomorphic Post-Transplantation Lymphoproliferative Disorders after SOT. Methods: We present retrospective data on 46 pediatric patients diagnosed with monomorphic Post-Transplantation Lymphoproliferative Disorders with Non-Hodgkin Lymphoma (NHL) after SOT in our Institution between 2001 and 2024. Results: Twenty four of the 46 were male, and 22 were female, and mean age at the time of diagnosis of PTLD was 8 years (age range, 11 months to 17 years). PTLD was diagnosed at a median time of 36 months after the organ transplant, with a significantly shorter interval in liver (20/46), 31 months, versus heart (15/46) or kidney (11/46) graft recipients (48- and 42-months years, respectively p < 0,05). Most common histopathology subtypes were Burkitt in 20/46 (44%), Diffuse Large B-cell lymphoma (DLBCL) in 19/46 (41%) and other NHL in 7/46 (15%). Most common sites were abdominal (17/46), followed by cervical and axillary lymph nodes (12/46). Murphy staging system revealed: Stage I (5/46 - 11%), Stage II (5/46 - 11%) and Stage III (33/46 -72%). Stage IV diseases with bone marrow (1/46 – 2%) and/or Central nervous system Involvement (CNS) (2/46 - 4%). The treatment carried out was reduction of immunosuppression and rituximab in 18 patients, with chemotherapy, rituximab and reduction of immunosuppression in 28 patients. In one relapse there was a need for bone marrow transplantation. No differences in outcome were observed between Early (22/46) and late-onset (24/46) PTLD and EBV-positive (14/46) or EBV-negative (25/46) PTLD, respectively. The 5-year overall and event-free survival were 91% and 83%, respectively. Conclusion: The outcome of m-PTLD has clearly improved as a result of the introduction of more uniform treatment protocols and improved supportive care, instaging and response monitoring. The majority of had a good response with chemotherapy and/or rituximab.