Post-Transplant Lymphoproliferative Disease (PTLD) after Allogeneic Hematopoietic Stem Cell Transplantation: Biology and Treatment Options

Metachronous spinal cord involvement B cell and subcutaneous tissue involvement NK/T cell lymphoid proliferations and lymphomas arising in post-transplantation mimicking general NK/T cell lymphoma: a case report and review of the literature

Lymphoid proliferations and lymphomas arising in post-transplantation are potentially life-threatening complications after solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT). The lymphoid proliferations and lymphomas arising in post-transplantation originating from different cell lineages in the same patient are highly unusual. Herein, we delineate a case of isolated spinal cord involvement with B cell lymphoid proliferations and lymphomas arising in post-transplantation at 11 months post-transplantation, which was successfully treated with chemotherapy and intrathecal injection. Six months later, the patient again developed lymphoma arising in post-transplantation, presenting with predominant subcutaneous tissue involvement deriving from EBV-positive NK/T cells, and received four courses of chemotherapy. Ultimately, she achieved complete remission (CR). The report further contributes to our new insights into the unusual clinical presentations of lymphoid proliferations and lymphomas arising in post-transplantation.

Pulmonary complications of bone marrow transplantation

Bone marrow transplantation, now often known as haematopoietic stem cell transplantation (HSCT), is a complex choreographed procedure used to treat both acquired and inherited disorders of the bone marrow. It has proven invaluable as therapy for haematological and immunological disorders, and more recently in the treatment of metabolic and enzyme disorders. As the number of performed transplants grows annually, and with patients enjoying improved survival, a knowledge of both early and late complications of HSCT is essential for respiratory trainees and physicians in practice. This article highlights the spectrum of respiratory complications, both infectious and non-infectious, the timeline of their likely occurrence, and the approaches used for diagnosis and treatment, keeping in mind that more than one entity may occur simultaneously. As respiratory issues are often a leading cause of short- and long-term morbidity, consideration of a combined haematology/respiratory clinic may prove useful in this patient population.

Posttransplant complications: molecular mechanisms and therapeutic interventions

Posttransplantation complications pose a major challenge to the long-term survival and quality of life of organ transplant recipients. These complications encompass immune-mediated complications, infectious complications, metabolic complications, and malignancies, with each type influenced by various risk factors and pathological mechanisms. The molecular mechanisms underlying posttransplantation complications involve a complex interplay of immunological, metabolic, and oncogenic processes, including innate and adaptive immune activation, immunosuppressant side effects, and viral reactivation. Here, we provide a comprehensive overview of the clinical features, risk factors, and molecular mechanisms of major posttransplantation complications. We systematically summarize the current understanding of the immunological basis of allograft rejection and graft-versus-host disease, the metabolic dysregulation associated with immunosuppressive agents, and the role of oncogenic viruses in posttransplantation malignancies. Furthermore, we discuss potential prevention and intervention strategies based on these mechanistic insights, highlighting the importance of optimizing immunosuppressive regimens, enhancing infection prophylaxis, and implementing targeted therapies. We also emphasize the need for future research to develop individualized complication control strategies under the guidance of precision medicine, ultimately improving the prognosis and quality of life of transplant recipients.

Efficacy of NKG2D CAR-T cells with IL-15/IL-15Rα signaling for treating Epstein-Barr virus-associated lymphoproliferative disorder

Epstein-Barr virus (EBV) related post-transplant lymphoproliferative disorder (EBV-PTLD) is a life-threatening complication after hematopoietic stem cell transplantation (HSCT) or solid organ transplantation (SOT), for which no standard therapeutic means have been developed. Significant increase expression of natural killer group 2 member D ligands (NKG2DLs) was observed on B-lymphoblastoid cells of EBV-PTLD, indicating NKG2DLs as potential therapeutic targets for treatment of EBV-PTLD. In this study, the recombinant constructs of NKG2D CAR and IL-15/IL-15Rα-NKG2D CAR were generated with a retroviral vector and then transduced to human T cells to produce NKG2D CAR-T and IL-15/IL-15Rα-NKG2D CAR-T cells, respectively. B-lymphoblastoid cell lines (B-LCLs) and the xenografted mouse models were established to evaluate the efficacy of these CAR-T cells. IL-15/IL-15Rα-NKG2D CAR-T cells exhibited superior proliferation and antigen-specific cytotoxic effect compared to NKG2D CAR-T, as IL-15/IL-15Rα signaling promoted the expansion of less differentiated central memory T cells (TCM) and increased expression of CD107a and IFN-γ. Moreover, EBV DNA load was dramatically reduced, and 80% B-LCL cells were eliminated by IL-15/IL-15Rα-NKG2D CAR-T cells after co-culturing. In-vivo study confirmed that IL-15/IL-15Rα-NKG2D CAR-T cell therapy significantly enhanced antiviral efficacy in mice, as the serum load of EBV after IL-15/IL-15Rα-NKG2D CAR-T cell infusion was 1500 times lower than the untreated control (P < 0.001). The enhanced efficacy of IL-15/IL-15Rα-NKG2D CAR T cells was probably due to the IL-15/IL-15Rα signaling improved homing and persistence of NKG2D CAR-T cells in vivo, and increased the production of IFN-γ, Perforin, and Granulysin. In conclusion, NKG2D CAR-T cells co-expressing IL-15/IL-15Rα promoted the central memory CAR T cell proliferation and improved the homing and persistence of CAR T cells in vivo, resulting in enhanced anti-tumor and anti-viral effects in treating EBV-PTLD.

Cutaneous Post-transplant Lymphoproliferative Disorder

Post-transplant lymphoproliferative disorders (PTLD) involve T- or B-cell proliferation in an immunosuppressed transplant recipient. It usually presents at extra-nodal sites and can affect several organs. Cutaneous manifestations of PTLD are relatively rare and can be very heterogeneous. We report a case of a 36-year-old male cardiac transplant recipient on long-term immunosuppression (ciclosporin, azathioprine, and prednisolone) who presented with a three-month history of a painless ulcer on the right lower leg. A skin biopsy showed a dermal atypical lymphoid infiltrate positive for PAX5, CD20 and MUM1 on immunohistochemistry and EBV with in-situ hybridisation and a 70% Ki-67 cell proliferation index. A whole body fluorodeoxyglucose (FDG) positron emission tomography (PET) scan showed increased tracer uptake corresponding to the site of the cutaneous ulcer, the anterior cortex of the right lower tibia, an area adjacent to the right superficial femoral artery and the right inguinal node. These findings were in keeping with monomorphic B-cell post-transplant lymphoproliferative disorder (PTLD) consistent with diffuse large B-cell lymphoma, non-germinal centre subtype. Cessation of azathioprine and treatment with an anti-CD20 antibody, rituximab, led to clinical resolution of the ulcer and a negative FDG-PET scan, with no disease recurrence to date. We present a rare case of monomorphic PTLD with cutaneous involvement, presenting with a solitary, painless ulcer, which was successfully treated with a reduction in immunosuppression and additional rituximab monotherapy, given the aggressive subtype. PTLD can arise many years post-transplant and is a serious, potentially life-threatening complication. Therefore, early recognition and prompt treatment are of paramount importance.

Improving the safety of CAR-T-cell therapy: The risk and prevention of viral infection for patients with relapsed or refractory B-cell lymphoma undergoing CAR-T-cell therapy

Chimeric antigen receptor (CAR) T-cell therapy, an innovative immunotherapeutic against relapsed/refractory B-cell lymphoma, faces challenges due to frequent viral infections. Despite this, a comprehensive review addressing risk assessment, surveillance, and treatment management is notably absent. This review elucidates immune response compromises during viral infections in CAR-T recipients, collates susceptibility risk factors, and deliberates on preventive strategies. In the post-pandemic era, marked by the Omicron variant, new and severe threats to CAR-T therapy emerge, necessitating exploration of preventive and treatment measures for COVID-19. Overall, the review provides recommendations for viral infection prophylaxis and management, enhancing CAR-T product safety and recipient survival.

Clinical analysis of malignant lymphoma secondary to transplantation: the notorious lymphoproliferative disease

As one of the worst complications after solid organ transplantation (SOT) or hematopoietic stem cell transplantation (HSCT), post-transplant lymphoproliferative disorder (PTLD) usually progresses rapidly and accompanies with a high mortality rate, which is the most notorious adverse event threatening long-term survival of organ transplant recipients. PTLD is generally characterized by malignant clonal proliferation of lymphocytes, so the location of the disease is uncertain, the clinical symptoms and signs are very complex, lack of specificity, and it is easy to miss diagnosis and misdiagnosis in clinical practice, which will lead to low survival of patients after transplantation. To this end, the clinical data of two patients with PTLD were retrospectively studied, and characteristics of medical history, clinical manifestations, treatment process, curative effect and prognosis of the patients with PTLD were systematically analyzed and discussed, with a view to improving the novel understanding of PTLD in the field of hematology and oncology.

Post-transplant lymphoproliferative disorders (PTLD) in adolescents and young adults: A category in need of definition

Post-transplant lymphoproliferative disorders are a well-recognized complication of solid organ and stem cell transplantation. Much data has accumulated with respect to the pathobiology and clinical behavior of these lesions in the general post-transplant population as well as in the pediatric and adult age groups. However, information as to these lesions in the adolescent and young adult populations, which bridge the pediatric and adult groups, is limited. In this review, the focus is on this unique population of PTLD patients and their proliferations.

Updates in hematopoietic cell transplant and cellular therapies that enhance the risk for opportunistic infections

BACKGROUND

Infectious disease physicians may be asked to evaluate and manage a variety of infections in immunocompromised hosts undergoing hematopoietic cell transplant (HCT) and cellular therapies. Over the last decade, several advances in cellular therapy have occurred, with implications for the types of infectious complications that may be seen.

AIMS

The purpose of this review is to update the infectious disease physician on newer advances in HCT and cellular therapy, including haploidentical transplant, expanding indications for transplant in older individuals and children, and chimeric antigen receptor T-cells. We will review how these advances might influence infectious disease complications following HCT. We will also provide a perspective that infectious disease physicians can use to evaluate the degree of immune suppression in an individual patient to help determine the type of infections that may be encountered.

Rare Case of Pediatric Post-transplant Lymphoproliferative Disorder Presenting With Pleural Masses Complicated by Pleural Effusions

Post-transplant lymphoproliferative disorder is a complication in organ transplant recipients characterized by uncontrolled proliferation of B-lymphocytes, occurring in 6% of pediatric patients, with risk factors including primary Epstein-Barr virus infection, intensity of immunosuppression, and cytomegalovirus infection. The clinical symptoms are often nonspecific, and it is associated with a high mortality rate if left untreated. We describe a rare case of post-transplant lymphoproliferative disorder who presented with pleural-based masses resulting in pleural effusions.

Post-transplant lymphoproliferative disorder: Update on treatment and novel therapies

Post-transplant lymphoproliferative disorder (PTLD) is rare and heterogeneous lymphoid proliferations that occur as a result of immunosuppression following solid organ transplant (SOT) and haematopoietic stem cell transplant (HSCT) with the majority being driven by EBV. Although some histologies are similar to lymphoid neoplasms seen in immunocompetent patients, treatment of PTLD may be different due to difference in pathobiology and higher risk of treatment complications. The most common treatment approach in SOT PTLD after failing immunosuppression reduction (RIS) takes into consideration a risk-stratified sequential algorithm with rituximab +/- chemotherapy based on phase 2 studies. In HSCT PTLD, RIS alone and chemotherapy are usually ineffective making rituximab +/- RIS as the gold standard of frontline treatment. In this review, we give an update on the treatment of PTLD beyond RIS. We highlight the most recent studies that attempted to incorporate more aggressive chemotherapy regimens and novel treatments into the traditional risk-stratified sequential approach. We also discuss the role of EBV-cytotoxic T lymphocytes in treatment of EBV-driven PTLD. Other novel agents with potential role in PTLD will be discussed in addition to the challenges that could arise with chimeric antigen receptor T-cell therapy and immune checkpoint inhibitors in this population.

Newly onset cytopenias not always indicate a relapsing AML after allogeneic HSCT, a case of non-destructive post transplant lymphoproliferative disorder

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains an effective option for the treatment of intermediate and high-risk Acute myeloid leukemia (AML). Post-transplant lymphoproliferative disorder (PTLD) is related to the intensity of post-transplant immunosuppression. Although Epstein-Barr virus (EBV) seropositivity and reactivation can be a major risk factor for PTLD. A few PTLDs could be EBV negative. There are a very limited number of PTLD cases following HSCT in patients with AML. We present a differential diagnosis of cytopenias after allo-HSCT. This is the first report of an AML patient developing bone marrow EBV-negative PTLD relatively late in their post-transplant course.