Single agent efficacy of rituximab in childhood immunosuppression related lymphoproliferative disease: a United Kingdom Children's Cancer Study Group (UKCCSG) retrospective review

Management of paediatric monomorphic post-transplant lymphoproliferative disorders with low-intensity treatment: A multicentre international experience

BACKGROUND

Monomorphic post-transplant lymphoproliferative disorder (mPTLD) is a major cause of morbidity/mortality following solid organ transplant (SOT), with infection, mPTLD progression and organ rejection presenting equal risks. Balancing these risks is challenging, and the intensity of therapy required by individual patients is not defined. Although an increasing body of evidence supports the use of a stepwise escalation of therapy through reduction in immunosuppression (RIS) to rituximab monotherapy and low-dose chemo-immunotherapy, many centres still use B-cell non-Hodgkin lymphoma (B-NHL) protocols, especially when managing Burkitt/Burkitt-like (BL) PTLD. This study sought to define outcomes for children managed in the UK or Spanish centres using low-intensity first-line treatments.

PROCEDURE

Retrospective data were anonymously collected on patients younger than 18 years of age, with post-SOT mPTLD diagnosed between 2000 and 2020. Only patients given low-intensity treatment at initial diagnosis were included.

RESULTS

Fifty-six patients were identified. Age range was 0.9-18 years (median 10.7). Most (62.5%) had early-onset PTLD. Haematopathological analysis showed 75% were diffuse large B-cell like, 14.3% were BL and nine of 33 (27%) harboured a MYC-rearrangement. Stage III-IV disease was present in 78.6%. All but one had RIS, 26 received rituximab monotherapy and 24 low-dose chemo-immunotherapy, mostly R-COP. Intensified B-NHL chemotherapy was required in 10/56 (17.9%). There were a total of 13 deaths in this cohort, three related to PTLD progression. The 1-year overall survival (OS), event-free survival (EFS) and progression-free survival (PFS) were 92.8%, 78.6% and 80.2%, respectively.

CONCLUSIONS

R-COP provides an effective low-dose chemotherapy option. Escalation to more intensive therapies in the minority of inadequately controlled patients is an effective strategy.

Pre-Emptive Use of Rituximab in Epstein-Barr Virus Reactivation: Incidence, Predictive Factors, Monitoring, and Outcomes

Post-transplant lymphoproliferative disease (PTLD) is a fatal complication of hematopoietic cell transplantation (HCT) associated with the Epstein-Barr virus (EBV). Multiple factors such as transplant type, graft-versus-host disease (GVHD), human leukocyte antigens (HLA) mismatch, patient age, and T-lymphocyte-depleting treatments increase the risk of PTLD. EBV reactivation in hematopoietic cell transplant recipients is monitored through periodic quantitative polymerase chain reaction (Q-PCR) tests. However, substantial uncertainty persists regarding the clinically significant EBV levels for these patients. Guidelines recommend initiating EBV monitoring no later than four weeks post-HCT and conducting it weekly. Pre-emptive therapies, such as the reduction of immunosuppressive therapy and the administration of rituximab to treat EBV viral loads are also suggested. In this study, we investigated the occurrence of EBV-PTLD in 546 HCT recipients, focusing on the clinical manifestations and risk factors associated with the disease. We managed to identify 67,150 viral genomic copies/mL as the cutoff point for predicting PTLD, with 80% sensitivity and specificity. Among our cohort, only 1% of the patients presented PTLD. Anti-thymocyte globulin (ATG) and GVHD were independently associated with lower survival rates and higher treatment-related mortality. According to our findings, prophylactic measures including regular monitoring, pre-emptive therapy, and supportive treatment against infections can be effective in preventing EBV-related complications. This study also recommends conducting EBV monitoring at regular intervals, initiating pre-emptive therapy when viral load increases, and identifying factors that increase the risk of PTLD. Our study stresses the importance of frequent and careful follow-ups of post-transplant complications and early intervention in order to improve survival rates and reduce mortality.

Screening and Management of PTLD

Posttransplant lymphoproliferative disorder (PTLD) represents a heterogeneous group of lymphoproliferative diseases occurring in the setting of immunosuppression following hematopoietic stem cells transplant and solid organ transplantation. Despite its overall low incidence, PTLD is a serious complication following transplantation, with a mortality rate as high as 50% in transplant recipients. Therefore, it is important to establish for each transplant recipient a personalized risk evaluation for the development of PTLD based on the determination of Epstein-Barr virus serostatus and viral load following the initiation of immunosuppression. Due to the dynamic progression of PTLD, reflected in the diverse pathological features, different therapeutic approaches have been used to treat this disorder. Moreover, new therapeutic strategies based on the administration of virus-specific cytotoxic T cells have been developed. In this review, we summarize the available data on screening and treatment to suggest a strategy to identify transplant recipients at a higher risk for PTLD development and to review the current therapeutic options for PTLD.

Transcriptional regulators of human oncoviruses: structural and functional implications for anticancer therapy

Transcription is often the first biosynthetic event of viral infection. Viruses produce preferentially viral transcriptional regulators (vTRs) essential for expressing viral genes and regulating essential host cell proteins to enable viral genome replication. As vTRs are unique viral proteins that promote the transcription of viral nucleic acid, vTRs interact with host proteins to suppress detection and immune reactions to viral infection. Thus, vTRs are promising therapeutic targets that are sequentially and structurally distinct from host cell proteins. Here, we review vTRs of three human oncoviruses: HBx of hepatitis B virus, HBZ of human T-lymphotropic virus type 1, and Rta of Epstein-Barr virus. We present three cunningly exciting and dangerous transcription strategies that make viral infections so efficient. We use available structural and functional knowledge to critically examine the potential of vTRs as new antiviral-anticancer therapy targets. For each oncovirus, we describe (i) the strategy of viral genome transcription; (ii) vTRs' structure and binding partners essential for transcription regulation; and (iii) advantages and challenges of vTR targeting in antiviral therapies. We discuss the implications of vTR regulation for oncogenesis and perspectives on developing novel antiviral and anticancer strategies.

The clinical efficacy of Rituximab administration in autoimmunity disorders, primary immunodeficiency diseases and malignancies

Rituximab (RTX), as a monoclonal antibody-based immunotherapeutic intervention targeting CD20 on B cells, has proven efficacy in the treatment of patients with some immune-mediated diseases. In the present review, we provided information on the immunobiological mechanisms of signaling for RTX and its clinical applications, according to the immune-pathophysiology involved in the microenvironment of multiple diseases. We highlighted combination therapy, dose schedules, and laboratory monitoring, as well as the associated common and rare side effects to avoid. We also discussed the efficacy and safety of RTX-based therapeutic strategies and whether RTX therapy can be used as a promising treatment regimen for autoimmune diseases, primary immunodeficiency diseases, and malignancies. Our review highlights and supports the importance of collaboration between basic medical researchers and clinical specialists when considering the use of RTX in the treatment of various immune-mediated disorders.

Post-transplant lymphoproliferative disorders, Epstein-Barr virus infection, and disease in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

PTLD with the response-dependent sequential use of RIS, rituximab, and cytotoxic chemotherapy is recommended. Evidence gaps requiring future research and alternate treatment strategies including immunotherapy are highlighted.

Improvements in intestine transplantation

Transplantation of the intestine in children has presented significant challenges even as it has become a standard to treat nutritional failure due to short gut syndrome. These challenges have been addressed in part by significant improvements in short and long-term care. Noteworthy enhancements include reduced need for intestine transplantation, drug-sparing immunosuppressive regimens, immune monitoring, and improved surveillance and management of PTLD and non-adherence.

Post-transplant lymphoproliferative disorder in pediatric intestinal transplant recipients: A literature review

Intestinal transplantation is a successful treatment for children with intestinal failure, but has many potential complications. PTLD, a clinically and histologically diverse malignancy, occurs frequently after intestinal transplantation and can be fatal. The management of this disease is particularly challenging. The rejection-prone intestinal allograft requires high levels of immunosuppression, a precondition for PTLD. While EBV infection clearly plays a role in disease pathogenesis, the relatively naïve immune system of children is another likely contributor. As a result, pediatric intestine recipients have a higher risk of developing PTLD than other solid organ recipients. Other risk factors for disease development such as molecular and genomic changes that precipitate malignant transformation are not fully understood, especially among children. Studies on adults have started to describe the molecular pathogenesis of PTLD, but the genomic landscape of the malignancy remains largely undefined in pediatric intestinal transplant patients. In this review, we describe what is known about PTLD in pediatric patients after intestinal transplant and highlight current knowledge gaps to better direct future investigations in the pediatric population.

Sinusoidal CD30+ diffuse large B-cell lymphoma can masquerade as anaplastic large cell lymphoma in pediatric posttransplant lymphoproliferative disorders

Posttransplant lymphoproliferative disorder (PTLD) is a known complication of solid organ transplantation. Diffuse large B-cell lymphoma (DLBCL) is frequently seen in this setting. However, CD30+ DLBCL with sinusoidal pattern of involvement has not been reported in pediatric PTLD. We are reporting a 9-year-old female child presented with diffuse lymphadenopathy postheart transplantation. The pattern of involvement was suggestive of anaplastic large cell lymphoma, but the malignant cells were positive for B-cell markers and negative for anaplastic lymphoma kinase. The patient was treated aggressively with multiagent chemotherapy and rituximab. Accurate diagnosis in PTLD is paramount in making management decisions.

Post-transplant lymphoproliferative disorder of the pediatric airway: Presentation and management

OBJECTIVE

Post-transplant lymphoproliferative disorder (PTLD) is a rare complication of immunosuppression with little consensus on its evaluation and management. The purpose of this contemporary review is to describe a pediatric patient with PTLD of the airway and review the literature to provide multidisciplinary recommendations regarding management.

DATA SOURCES

Retrospective chart and literature review.

REVIEW METHODS

A pediatric patient with PTLD of the airway is described. An extensive literature search to review the existing data on pediatric PTLD of the upper airway was also performed.

RESULTS

A pediatric patient with mixed fetal/embryonal hepatoblastoma developed laryngo-tracheal PTLD following liver transplantation. Diagnostic positron emission tomography (PET) scan demonstrated multiple sites of abnormal fluorodeoxyglucose (FDG) uptake within the larynx, distal esophagus, cervical lymph nodes, and abdomen concerning for PTLD. Laryngeal biopsy demonstrated Epstein-Barr virus (EBV) positive cells confirming the diagnosis. Rituximab therapy and reduction of immunosuppression resulted in resolution of his laryngeal disease in 3 months. An extensive literature search to review the existing data on pediatric PTLD of the larynx and trachea revealed 14 reported cases.

CONCLUSIONS

PTLD of the pediatric airway is an EBV-associated disease that requires a high index of suspicion as patients can often present with non-specific signs and symptoms but progress to have significant airway compromise. Evaluation consists of peripheral blood polymerase chain reaction (PCR) assays, biopsy, and PET/CT imaging. Management options include reduction of immunosuppression and/or systemic therapies.

Establishment and operation of a Good Manufacturing Practice-compliant allogeneic Epstein-Barr virus (EBV)-specific cytotoxic cell bank for the treatment of EBV-associated lymphoproliferative disease

Epstein-Barr virus (EBV) is associated with several malignancies, including post-transplant lymphoproliferative disorder (PTLD). Conventional treatments for PTLD are often successful, but risk organ rejection and cause significant side effects. EBV-specific cytotoxic T lymphocytes (CTLs) generated in vitro from peripheral blood lymphocytes provide an alternative treatment modality with few side effects, but autologous CTLs are difficult to use in clinical practice. Here we report the establishment and operation of a bank of EBV-specific CTLs derived from 25 blood donors with human leucocyte antigen (HLA) types found at high frequency in European populations. Since licensure, there have been enquiries about 37 patients, who shared a median of three class I and two class II HLA types with these donors. Cells have been infused into ten patients with lymphoproliferative disease, eight of whom achieved complete remission. Neither patient with refractory disease was matched for HLA class II. Both cases of EBV-associated non-haematopoietic sarcoma receiving cells failed to achieve complete remission. Thirteen patients died before any cells could be issued, emphasizing that the bank should be contacted before patients become pre-terminal. Thus, this third party donor-derived EBV-specific CTL cell bank can supply most patients with appropriately matched cells and most recipients have good outcomes.

Risk factors for Epstein-Barr virus-related post-transplant lymphoproliferative disease after allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation is a successful treatment for hematologic malignancies and a variety of genetic and metabolic disorders. In the period following stem cell transplantation, the immune-compromised milieu allows opportunistic pathogens to thrive. Epstein-Barr virus-associated post-transplant lymphoproliferative disease can be a life-threatening complication for transplanted patients because of suppressed T-cell-mediated immunity. We analyzed possible risk factors associated with post-transplant lymphoproliferative disease in a cohort of over 1,000 patients. The incidence of post-transplant lymphoproliferative disease was 4%. Significant risk factors identified by multivariate analysis were: human leukocyte antigen-mismatch (P<0.001), serological Epstein-Barr virus mismatch recipient-/donor+ (P<0.001), use of reduced intensity conditioning (P=0.002), acute graft-versus-host disease grade II to IV (P=0.006), pre-transplant splenectomy (P=0.008) and infusion of mesenchymal stromal cells (P=0.015). The risk of post-transplant lymphoproliferative disease has increased in more recent years, from less than 2% before 1998 to more than 6% after 2011. Additionally, we show that long-term survival of patients with post-transplant lymphoproliferative disease is poor despite initial successful treatment. The 3-year survival rate among the 40 patients with post-transplant lymphoproliferative disease was 20% as opposed to 62% among patients without post-transplant lymphoproliferative disease (P<0.001). The study identifies patients at risk of post-transplant lymphoproliferative disease after transplantation in need of pre-emptive measures.

Post-transplant lymphoproliferative disease in pediatric solid organ transplant recipients

Post-transplant lymphoproliferative disease (PTLD) in solid organ transplant (SOT) recipients has become one of the most common forms of lymphoproliferation in childhood and is a serious complication of SOT. More than 90% of cases are of B-cell origin, Epstein Barr virus (EBV) positive and are mostly occurring in the early post-transplant period. Pathologically and clinically it is a heterogenous disease ranging from being responsive to reduced immunosuppression without further intervention to rapidly progressive fulminant PTLD requiring prompt initiation of therapy. Prognosis overall is favorable. Current treatment strategies as well new promising targeted immune-based therapies such as rituximab and EBV-specific cytotoxic T-lymphocytes are being discussed.

Antibody therapy of pediatric B-cell lymphoma

B-cell lymphoma in children accounts for about 10% of all pediatric malignancies. Chemotherapy has been very successful leading to an over-all 5-year survival between 80 and 90% depending on lymphoma type and extent of disease. Therapeutic toxicity remains high calling for better targeted and thus less toxic therapies. Therapeutic antibodies have become a standard element of B-cell lymphoma therapy in adults. Clinical experience in pediatric lymphoma patients is still very limited. This review outlines the rationale for antibody treatment of B-cell lymphomas in children and describes potential target structures on B-cell lymphoma cells. It summarizes the clinical experience of antibody therapy of B-cell lymphoma in children and gives an outlook on new developments and challenges for antibody therapy of pediatric B-cell lymphoma.

Rapid salvage treatment with virus-specific T cells for therapy-resistant disease

BACKGROUND

Viral infections are major complications after allogeneic hematopoietic stem cell transplantation (HSCT). During posttransplant immunosuppression the regular T-cell control is compromised. Even if treatment strategies against infections caused by herpes viruses such as cytomegalovirus, Epstein-Barr virus, and adenovirus have improved, the mortality rate is still considerable. If primary antiviral therapy fails or cannot be tolerated, adoptive therapy with virus-specific cytotoxic T cells (CTL) can be utilized.

METHODS

In this study, we used virus-specific CTLs to treat 8 patients suffering from severe viral infections after allogeneic HSCT. Using positive selection with HLA multimers and magnetic beads, we isolated CTLs from both frozen donor material as well as third-party donors within hours.

RESULTS

At 90 days after CTL infusions 7 out of 8 patients were still living. CTLs infused from third-party donors were detected in 5 of 6 patients up to 76 days after infusion. No graft-versus-host disease associated with CTL infusions was observed.

CONCLUSIONS

Our separation approach offers a rapid alternative for adoptive CTL therapy if primary antiviral treatment strategies fail. Because no prolonged expansion steps are needed, this method may be used for early treatment of patients suffering from life-threatening infectious complications.

Pre-emptive rituximab based on viraemia and T cell reconstitution: a highly effective strategy for the prevention of Epstein-Barr virus-associated lymphoproliferative disease following stem cell transplantation

This study investigated the efficacy of a pre-emptive strategy based on the combination of Epstein-Barr virus (EBV) viraemia and poor T cell reconstitution in preventing post-transplant lymphoproliferative disease (PTLD) following T cell depleted stem cell transplant (SCT). EBV viral load and immune reconstitution were prospectively monitored in 70 consecutive children undergoing SCT following reduced intensity conditioning with alemtuzumab. Patients who developed significant EBV viraemia (> 40 000 copies/ml blood) were treated pre-emptively with rituximab if they were within 3 months of SCT or their CD3 count was <0·3 × 10⁹ /l. Of 20/70 patients who developed significant EBV viraemia, 13 received pre-emptive rituximab. The incidence of PTLD was significantly reduced in the pre-emptive cohort compared to historical controls (1·4% vs. 21·7%, P = 0·003). This difference was more marked among viraemic patients (2·7% vs. 62·5%P < 0·0001). Patients treated with rituximab demonstrated significantly delayed B cell reconstitution at 1 year post-SCT but this was not associated with an increase in infectious mortality. In 6/6 patients >3 months post-SCT who had a CD3 count >0·3 × 10⁹ /l, reduced immunosuppression only resulted in successful resolution of EBV viraemia without PTLD. This strategy is safe and highly effective in preventing PTLD following T cell depleted SCT, and directs rituximab therapy to patients at highest risk of this complication.

Rituximab combined with autologous peripheral blood stem cell transplantation improve therapeutic effects of chemotherapy in pediatric patients with Burkitt's lymphoma

We report on 2 children with Burkitt's lymphoma accompanied by extensive extranodal involvement treated with chemotherapy and Rituximab in combination with autologous peripheral blood stem cell transplantation (Auto-PBSCT) regimens. No obvious side effects could be seen during the Rituximab therapy. Both children achieved complete remission with no relapse after being followed up for 4.3 and 4 years, respectively. Our limited experience show that Rituximab in combination with chemotherapy and Auto-PBSCT might have better therapeutic effects on Burkitt's lymphoma of children and the side effects of Rituximab therapy is minimal and can be well tolerated.

Generation of EBV-specific cytotoxic T cells that are resistant to calcineurin inhibitors for the treatment of posttransplantation lymphoproliferative disease

Epstein-Barr virus (EBV)-driven posttransplantation lymphoproliferative disease (PTLD) is a serious complication of immunosuppression after either stem cell transplantation (SCT) or solid organ transplantation (SOT). Adoptive transfer of EBV-specific cytotoxic T lymphocytes (EBV-CTLs) is an effective prophylaxis and treatment for PTLD after SCT, but not for PTLD after SOT when pharmacologic immunosuppression cannot be discontinued. We report the generation of calcineurin (CN) mutants that render EBV-CTL resistant to the immunosuppressants tacrolimus (FK506) and cyclosporin A (CsA): mutant CNa12 confers resistance to CsA but not FK506, and mutant CNa22 confers resistance to FK506 but not CsA, whereas mutant CNb30 renders CTLs resistant to both calcineurin inhibitors. Untransduced EBV-CTLs do not proliferate in the presence of FK506/CsA. However, EBV-CTLs transduced with a retroviral vector coding for these mutants retain the ability to both proliferate and secrete normal levels of interferon-gamma in the presence therapeutic levels of FK506 (CNa12), CsA (CNa22), or both (CNb30). The cytotoxicity and phenotype of EBV-CTL lines were unaffected by expression of these mutant CNs. This approach should allow effective immunotherapy with EBV-CTLs in the SOT setting without risking the graft by reduction in immunosuppression, and represents a generic approach to improving immunotherapy in the face of immunosuppression.

Post cardiac transplantation lymphoproliferative disorder presenting as t(8;14) Burkitt leukaemia/lymphoma treated with low intensity chemotherapy and rituximab

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) occasionally presents as Burkitt lymphoma/L3 leukaemia (BLL).

PROCEDURE

We reviewed records of cases of PTLD post-cardiac transplantation (1990-2007) occurring in our unit.

RESULTS

There were 15 episodes in 13 patients including four cases of EBV-driven Burkitt-type disease with t(8;14) translocations presenting with advanced stage disease. The first case was treated with a variety of low dose chemotherapy combinations. Despite problems during therapy he obtained complete remission, but died from complications of pre-existing cardiac allograft vasculopathy 7 months later. The subsequent three cases were treated with a UKCCSG low stage lymphoma protocol, NHL 9001 and Rituximab. They remain in complete remission.

CONCLUSIONS

In the context of PTLD the prognostic significance of advanced stage EBV-driven BLL with the t(8;14) translocation may be different to that in immunocompetent children.