[Interpretation of lymphoid proliferations and lymphomas associated with immune deficiency and dysregulation in the 5th edition WHO classification of haematolymphoid tumours].

The fifth edition of the World Health Organization (WHO) classification of lymphohematopoietic system tumors updated the terminology, types of lesions, diagnostic criteria, nomenclature, and other aspects of lymphoid proliferations and lymphomas associated with immune deficiency and dysregulation. The important updates and main changes in this section were briefly introduced, in order to guide the precise classification of lymphoid proliferations and lymphomas associated with immune deficiency and dysregulation, and standardize pathological reports.

[Clinicopathological features of primary mucosal CD30-positive T-cell lymphoproliferative disorders].

Objective: To investigate the clinicopathological features and differential diagnosis of primary mucosal CD30-positive T-cell lymphoproliferative disorders (pmCD30+TLPD). Methods: Eight cases of pmCD30+TLPD diagnosed from 2013 to 2023 at the Department of Pathology, Beijing Friendship Hospital Affiliated to Capital Medical University and Beijing Ludaopei Hospital were retrospectively collected. The immunophenotype, EBV infection status and T-cell receptor (TCR) clonability of tumor cells were examined. The clinicopathological features were analyzed and related literatures were reviewed. Results: There were 5 females and 3 males, aged 28 to 73 years, without B symptoms, lack of trauma and autoimmune diseases. Seven cases occurred in oral mucosa and one in anal canal mucosa. Submucosal nodules with ulcerations were presented in all cases except one, which only submucosal nodule. Morphologically, there was different distribution of allotypic lymphocytes in inflammatory background. Four cases showed "kidney-shaped", "embryonic" and "horseshoe-shaped" cells, and one case resembled Hodgkin and Reed/Sternberg (HRS) cells. Allotypic lymphocytes expressed CD3 (7/8), CD4+/CD8-(7/8) and CD4-/CD8-(1/8). CD30 was uniformly strongly positive while ALK and CD56 were negative. In situ hybridization of EBER was negative in five cases (5/5). Clonal TCR gene rearrangement was positive in two cases. Four patients did not receive radiotherapy or chemotherapy. All the seven patients survived without disease except one died due to concurrent leukopenia. Conclusions: pmCD30+TLPD had a broad morphological spectrum and could be easily confused with primary cutaneous CD30+TLPD and systemic ALK-negative anaplastic large cell lymphoma involving mucosa, which may lead to misdiagnosis. Although the majority of the cases had a favorable prognosis, a few cases relapsed or progressed to lymphoma.

Clinical epidemiology of Epstein-Barr virus-associated Lymphoproliferative Disorders (EBV-LPDs) in hospitalized children: A six-year multi-institutional study in China.

BACKGROUND: Epstein-Barr virus-associated lymphoproliferative disorders (EBV-LPDs) are a group of disorders involving lymphoid tissues or lymphocytes. The epidemiology and economic burden of hospitalized children with EBV-LPDs in China have not been well studied. This study aimed to reveal the epidemic characteristics and disease burden of EBV-LPDs among the Chinese hospitalized children, providing strategies for the prevention and management. METHODS: This study was based on the FUTang Updating medical REcords (FUTURE) database of China and collected the medical records from 27 tertiary children's hospitals between January 2016 and December 2021 in China, counting five types of EBV-LPDs, namely EBV-positive T-cell lymphoproliferative disease, NK/T cell lymphoma, extranodal NK/T-cell lymphoma (nasal type), systemic EBV-positive T-cell lymphoproliferative disease of childhood and posttransplant lymphoproliferative disorders. We conducted a retrospective syhthesis and analysis of the epidemiological characteristics, expenses, length of stay (LOS), as well as complications among hospitalized children diagnosed with five types of EBV-LPDs and compared parameters using appropriate statistical tests. RESULTS: The study described 153 children aged 0-18 years hospitalized with EBV-LPDs from 2016 to 2021 in the FUTURE database. The male-to-female ratio was 1.10:1, and more than half of the age distribution was in the 6-12 y group. Among EBV-LPDs cases, EBV+ T-LPD accounted for the largest proportion (65.36%). Complications were presented in 93 children with EBV-LPDs, mainly hemophagocytic lymphohistiocytosis (HLH). The median LOS of NKTL was 26.5 days [interquartile range (IQR) = 3-42], which was the longest among EBV-LPDs. The median hospitalization cost of PTLD was 10 785.74 United States dollars (IQR = 7 329.38-16 531.18), which was the heaviest among EBV-LPDs. CONCLUSIONS: Compared with the total number of hospitalized children in China during the same period and in the same age group, the proportion of EBV-LPD is very low. EBV-LPD can develop in all age groups, but it is more common in school-age children. Among 5 EBV-LPDs, the disease with the highest proportion is EBV+ T-LPD. The overall disease burden of EBV-LPD was heavy, especially the economic burden. HLH was one of the most common complications, which could directly affect the burden of patients because of prolonged hospitalization. These data are taken from a very large database, illustrating the epidemiological and economic burden of EBV-LPDs hospitalized children in China, which enriched the existing epidemiological and disease burden content of EBV-LPDs.

T-Cell Posttransplant Lymphoproliferative Disorders After Allogeneic Hematopoietic Stem Cell Transplantation: Case Series and Systemic Review.

Posttransplant lymphoproliferative disorder (PTLD) is a rare lymphoid and/or plasmocytic proliferation that occurs after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We aimed to identify the pathologic features and clinical outcomes of T-cell PTLD, an extremely rare subtype of PTLD, after allo-HSCT. In this study, six allo-HSCT recipients with T-cell PTLD from five transplant centers in China were enrolled. All the T-cell PTLD were donor-derived, and three patients were with monomorphic and three with polymorphic types, respectively. All patients received cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-based chemotherapy. Five patients achieved complete response (CR), and one experienced progressive disease (PD). The median time from HSCT to onset was 4 (range: 0.6-72) months, analyzed in combination with the other 16 patients with T-cell PTLD identified from previous reports. About 56.3% of the T-cell samples (9/16) were positive for in situ hybridization with an Epstein-Barr virus (EBV)-encoded small nuclear early region (EBER ISH). CHOP-based chemotherapy might be the optimal strategy for patients who showed no response to empiric therapy with a CR rate of 87.5%. In conclusion, our study observed that T-cell PTLD has distinct clinical manifestations and morphological features, which characterized by less relation to EBV, later occurrence, and poorer prognosis when compared with B-cell PTLD.

Hydroa vacciniforme lymphoproliferative disorder: a retrospective study of 42 paediatric cases.

Hydroa vacciniforme lymphoproliferative disorder (HVLPD) is a rare disease related to Epstein-Barr virus (EBV), mainly in children, and is an EBV-associated cutaneous T and natural killer (NK) cell lymphoproliferative disorder. The disorder in some patients may progress to EBV-associated systemic T or NK-cell lymphoma. To summarize the characteristics of HVLPD in Chinese paediatric patients and to examine the risk factors indicating poor prognosis. We performed a retrospective analysis of patients with HVLPD from the Department of Dermatology, Beijing Children's Hospital. Based on diagnosis, medical history, examination results, and immunophenotype, we analysed HVLPD in 42 paediatric cases in order to examine the clinical features, prognoses, and risk factors. Forty-two paediatric patients were enrolled, with a median onset age of five years. All patients presented with papulovesicular lesions, and 32 systemic HVLPD (sHVLPD) patients had systemic symptoms, including fever, lymphadenopathy, hepatomegaly, splenomegaly, and liver dysfunction. Of the sHVLPD cases, 13 also had severe mosquito bite allergy (SMBA). Twenty-five cases were T-type, and nine were CD56+-dominant type. Follow-up data showed that 12 patients had complete remission, and three patients died. SMBA is a risk factor for disease progression in patients with HVLPD, and the pathological CD56+-dominant phenotype is associated with poor prognosis.

[Interpretation of T-cell and NK-cell lymphoid proliferations and lymphomas in the 5th edition of the WHO classification of haematolymphoid tumours].

The 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumours used the hierarchical system to classify T-cell and NK-cell lymphoid proliferations and lymphomas (T/NK-LPD/LYM) based on research advances and clinicopathological characteristics of the diseases. In this edition of classification, tumour-like lesions were included, some tumors were added/deleted, the names or terms of certain diseases were refined, and the diagnostic criteria or subtypes of some diseases were revised. This group of diseases was reintegrated from non-clonal hyperplasia to highly aggressive lymphoma, which would further reflect the nature of T/NK-LPD/LYM and benefit to clinical application.

Atypical lymphoplasmacytic and immunoblastic proliferation: A Systematic Review.

Atypical lymphoplasmacytic and immunoblastic proliferation (ALPIBP) was first reported in 1984 as characteristic histological findings in lymph nodes associated with autoimmune diseases, but it has not been clearly defined to date. To summarize the histological characteristics and clinical diagnoses associated with ALPIBP, we searched MEDLINE and EMBASE for all peer-reviewed articles using keywords including "atypical lymphoplasmacytic and immunoblastic lymphadenopathy" from their inception to December 27, 2023. We also summarized the courses of three cases with a pathological diagnosis of ALPIBP. Nine articles with 52 cases were included. Among the total of 55 cases, including the three from our institution, the median age of the cases was 63.5 years with a female predominance (69.5%). Lymphadenopathy was generalized in 65.6% and regional in 34.4% of cases. RA (24.4%), SLE (24.4%), and autoimmune hemolytic anemia (20.0%), were common clinical diagnoses. A combination of cytotoxic chemotherapy was used in 15.6% of cases due to the suspicion of malignancy. Nodal T-follicular helper cell lymphoma, angioimmunoblastic type, methotrexate-associated lymphoproliferative disorders, and IgG4-related diseases were listed as important diseases that need to be pathologically differentiated from ALPIBP. This review summarizes the current understanding of the characteristics of ALPIBP. Given that underrecognition of ALPIBP could lead to overdiagnosis of hematological malignancy and unnecessary treatment, increased awareness of the condition in pathologists and clinicians is crucial.

Post-transplant lymphoproliferative disorder associated Epstein-Barr virus DNAemia after liver transplantation in children: Experience from single center.

The most prevalent malignancy that complicates both adult and pediatric solid organ transplantation is post-transplant lymphoproliferative disorder (PTLD). This study aimed to analyze the clinical and pathological characteristics, treatments, and outcomes of Epstein-Barr virus (EBV) DNAemia and PTLD in pediatric liver transplant recipients. A retrospective chart review was performed on 112 patients less than 18 years of age who underwent isolated orthotopic liver transplantation (OLT) between 2010 and 2022 at Ege University Children's Hospital. Data gathered for 1-year post-OLT included age at OLT, EBV, immunoglobulin (Ig)M/IgG status of the donor and recipient, indication for OLT, induction regimen, all immunosuppression levels, date and result of EBV polymerase chain reaction testing, rejection episodes documented by liver biopsy, and the development of PTLD. Forty-nine patients (43.75%) developed EBV DNAemia (median interval from surgery: 2 months, min-max: 2-36), of which 43 (87.8%) grafts came from living donors, and 6 (12.2%) came from deceased donors. Nine (18.4%) patients died during follow-up, and eight (16.3%) developed PTLD. Of these 8 patients; five patients developed EBV-related disease, one child developed hemophagocytic lymphohistiocytosis, one developed aplastic anemia, and one child developed B cell lymphoma. When PTLD patients and without-PTLD patients were compared, pediatric intensive care unit hospitalization, abnormal bone marrow biopsy findings, lymphadenopathy, age at diagnosis of EBV DNAemia, EBV viral load, tacrolimus (FK 506) pre-infection, were higher and tacrolimus 1-month levels were lower in patients with PTLD (p < 0.05). In logistic regression analysis, we showed that the age at diagnosis of EBV DNAemia was significantly higher in children with PTLD (p = 0.045; OR: 1.389; 95% CI: 1.007-1.914). PTLD is a rare but severe complication associated with EBV after OLT. This study demonstrated that PTLD is associated with older age, higher tacrolimus blood levels before EBV DNAemia, and higher peak EBV viral load at 1 month of EBV DNAemia.

Intraoral CD30+ T-Cell Lymphoproliferative Disorder with Lymphomatoid Papulosis Type C Features Mimics Lymphoma Histopathologically and Immunohistochemically.

BACKGROUND: Previous studies have shown that at least a of intraoral eosinophilic ulcer is best classified as a CD30 + T-cell lymphoproliferative disorder (LPD), with histopathology reminiscent of lymphomatoid papulosis (LyP) of the skin. Microscopically, a mixed population of inflammatory cells, often including eosinophils and varying numbers of atypical lymphoid cells, frequently expressing CD30, is typical for LyP, whose clinicopathological spectrum includes type A, B, C, D, E, and LyP with DUSP22/IRF4 rearrangement. To date, about 27 intraoral LyP cases have been reported. Of them, 7 cases were diagnosed as LyP type C, which is frequently confused with anaplastic large cell lymphoma (ALCL) on histopathology. METHODS: A 60-year-old male was referred for a one-month history of a tongue ulcer. RESULTS: Microscopy showed numerous subepithelial atypical large lymphoid cells, which expressed CD4 (with partial loss of CD3, CD5, and CD7), CD8 (few cells), CD30 (about 50%, in non-diffuse pattern with size variability), TIA-1, and Ki-67 (85%), without staining for CD56, ALK, LMP1, and EBER1/2, concerning for a diagnosis of ALCL. However, after three weeks, the lesion completely healed. CONCLUSION: We present here a rare case of intraoral CD30+ T-cell LPD that we believe is the oral counterpart of cutaneous LyP type C.

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.

Epstein-Barr Virus Monitoring after an Allogeneic Hematopoietic Stem Cell Transplant: Review of the Recent Data and Current Practices in Canada.

Epstein-Barr virus-related post-transplantation lymphoproliferative disorder (EBV-PTLD) is a serious complication following hematopoietic stem cell transplantation (HSCT). A pre-emptive strategy using rituximab, which aims to manage patients early at the time of EBV reactivation to avoid PTLD, has been recommended by the most recent ECIL-6 guidelines in 2016. However, there is still a great heterogeneity of viral-load monitoring protocols, targeted patient populations, and pre-emptive treatment characteristics between centers, making precise EBV monitoring recommendations difficult. We conducted a literature review from the most recent publications between 1 January 2015 and 1 August 2023, to summarize the emerging data on EBV-PTLD prevention strategies in HSCT recipients, including the EBV-DNA threshold and use of rituximab. We also present the results of a survey of current practices carried out in 12 of the main HSCT centers across Canada. We confirm that pre-emptive rituximab remains an efficient strategy for EBV-PTLD prevention. However, there is an urgent need to perform prospective, randomized, multicentric trials with larger numbers of patients reflecting current practices to determine the best clinical conduct with regards to rituximab dosing, timing of treatment, and criteria to initiate treatments. Longer follow-ups will also be necessary to assess patients' long-term outcomes.

[Clinical analysis of 18 children with aggressive mature B-cell lymphoma after liver transplantation].

Objective: To summarize the clinical characteristics, prognostic factors and treatment outcomes of childhood aggressive mature B-cell lymphoma after liver transplantation. Methods: This retrospective study included 18 children with newly diagnosed aggressive mature B-cell lymphoma after liver transplantation and treated from June 2018 to June 2022 in the Department of Hematology and Oncology of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine. Clinical characteristics, treatment and outcomes of patients at last evaluation were analyzed. Overall survival (OS) and event free survival (EFS) rates were calculated by Kaplan-Meier method and Log-Rank analysis was performed to find factors of poor prognosis. Results: Among all 18 patients, there were 6 males and 12 females, and the age of onset was 40 (35, 54) months. The interval from transplant to tumor diagnosis was 21 (17, 35) months and 5 patients had early onset disease (<1 year since transplant). Seventeen patients had abdominal lesions. Diarrhea, vomiting and abdominal masses were the main clinical manifestations. All patients were Epstein-Barr virus (EBV) related posttransplant lymphoproliferative disorders (PTLD). One patient received individualized therapy due to critical sick at diagnosis, and the remaining 17 patients received CP (cyclophosphamide, methylprednisolone plus rituximab) and (or) modified EPOCH (prednisone, etoposide, doxorubicin, vincristine, cyclophosphamide plus rituximab) regimens. Of all 18 patients, 15 cases got complete response, 2 cases got partial response, 1 patient died of severe infection. The 2-year OS and EFS rates of 18 patients were (94±5)% and (83±8)%, respectively. None of age, gender or early onset disease had effect on OS and EFS rates in univariate analysis (all P>0.05). Conclusions: The symptoms of PTLD were atypical. Close surveillance of EBV-DNA for patients after liver transplantation was crucial to early stage PTLD diagnosis. CP or modified EPOCH regimen was efficient for pediatric patients with aggressive mature B cell lymphoma after liver transplantation.

Case report: Non-EBV associated cerebral vasculitis and cerebral hemorrhage in X-linked lymphoproliferative disease.

X-linked lymphoproliferative disease (XLP) is a rare genetic disorder characterized by immune dysregulation. The three most common clinical phenotypes are EBV-associated infectious mononucleosis (FIM), abnormal gammaglobulinemia, and lymphoma. We present a rare case of XLP1 with neurovasculitis, which is non-EBV-related and involves multiple systems, a condition rarely seen in children. The patient initially presented with an unsteady gait, which progressively evolved into language and consciousness disorders. Additionally, CT scans revealed multiple nodules in the lungs. Subsequent genetic testing and brain tissue biopsy confirmed the diagnosis: XLP1-related cerebral vasculitis and cerebral hemorrhage. Tragically, during the diagnostic process, the child experienced a sudden cerebral hemorrhage and herniation, ultimately resulting in fatality. This case offers a comprehensive insight into XLP1-related cerebral vasculitis and cerebral hemorrhage, underscoring the significance of early diagnosis and prompt treatment, while also imparting valuable clinical experience and lessons to the medical community.

The IPTA Nashville consensus conference on post-transplant lymphoproliferative disorders after solid organ transplantation in children: IV-consensus guidelines for the management of post-transplant lymphoproliferative disorders in children and adolescents.

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders (PTLD) after pediatric solid organ transplantation. This report addresses the outcomes of deliberations by the PTLD Management Working Group. A strong recommendation was made for reduction in immunosuppression as the first step in management. Similarly, strong recommendations were made for the use of the anti-CD20 monoclonal antibody (rituximab) as was the case for chemotherapy in selected scenarios. In some scenarios, there is uncoupling of the strength of the recommendations from the available evidence in situations where such evidence is lacking but collective clinical experiences drive decision-making. Of note, there are no large, randomized phase III trials of any treatment for PTLD in the pediatric age group. Current gaps and future research priorities are highlighted.

Comparative analysis of tabelecleucel and current treatment in patients with Epstein-Barr virus-positive post-transplant lymphoproliferative disease following hematopoietic cell transplant or solid organ transplant.

AIMS: With recent European Union marketing authorization, tabelecleucel is the first off-the-shelf, allogeneic Epstein-Barr virus (EBV)-specific T-cell immunotherapy approved for the treatment of relapsed/refractory EBV-positive post-transplant lymphoproliferative disease (EBV+ PTLD). In the absence of a control arm, real-world evidence can provide a comparative benchmark for single-arm studies in ultra-rare populations. This study assessed the treatment effect of tabelecleucel in the single-arm phase 3 ALLELE study (NCT03394365) versus a treatment group from a multinational, multicenter retrospective chart review study (RS002) of patients with EBV+ PTLD. METHODS: In ALLELE, patients had disease relapsed/refractory to rituximab ± chemotherapy and received tabelecleucel 2x106 cells/kg on days 1, 8, and 15 in 35-day cycles. Patients in RS002 had disease relapsed/refractory to rituximab ± chemotherapy and received next line of systemic therapy between January 2000 and December 2018. Propensity score-based standardized mortality/morbidity ratio weighting was used to achieve balance between treatment and comparator arms. Kaplan-Meier estimators and Cox regression models were used to compare overall survival (OS) in the re-weighted sample. RESULTS: 30 patients (n = 14 hematopoietic cell transplant [HCT], n = 16 solid organ transplant [SOT]) from ALLELE (data cutoff: November 2021) and 84 patients (n = 36 HCT, n = 48 SOT) from RS002 (data lock: January 2021) were included. Median time from diagnosis to first tabelecleucel dose (ALLELE) or start date of next line of systemic therapy (RS002) was 3.6 months. Tabelecleucel was associated with a substantial OS benefit compared with current treatment, with an unadjusted HR of 0.47 (95% confidence interval [CI] 0.25-0.88) and adjusted HR of 0.37 (95% CI 0.20-0.71) when using the start date of the next line of therapy as the index date. Sensitivity analyses yielded consistent results. CONCLUSIONS: In this study of real-world data, tabelecleucel was associated with an OS benefit among patients with R/R EBV+ PTLD for whom there is high unmet need.

Pediatric Kidney Transplantation: Cancer and Cancer Risk.

Children with end-stage kidney disease (ESKD) face a lifetime of complex medical care, alternating between maintenance chronic dialysis and kidney transplantation. Kidney transplantation has emerged as the optimal treatment of ESKD for children and provides important quality of life and survival advantages. Although transplantation is the preferred therapy, lifetime exposure to immunosuppression among children with ESKD is associated with increased morbidity, including an increased risk of cancer. Following pediatric kidney transplantation, cancer events occurring during childhood or young adulthood can be divided into two broad categories: post-transplant lymphoproliferative disorders and non-lymphoproliferative solid tumors. This review provides an overview of cancer incidence, types, outcomes, and preventive strategies in this population.

BCR signaling is required for posttransplant lymphoproliferative disease in immunodeficient mice receiving human B cells.

Posttransplant lymphoproliferative disease (PTLD) is a major therapeutic challenge that has been difficult to study using human cells because of a lack of suitable models for mechanistic characterization. Here, we show that ex vivo-differentiated B cells isolated from a subset of healthy donors can elicit pathologies similar to PTLD when transferred into immunodeficient mice. The primary driver of PTLD-like pathologies were IgM-producing plasmablasts with Epstein-Barr virus (EBV) genomes that expressed genes commonly associated with EBV latency. We show that a small subset of EBV+ peripheral blood-derived B cells expressing self-reactive, nonmutated B cell receptors (BCRs) expand rapidly in culture in the absence of BCR stimulation. Furthermore, we found that in vitro and in vivo expansion of EBV+ plasmablasts required BCR signaling. Last, treatment of immunodeficient mice with the BCR pathway inhibitor, ibrutinib, delays onset of PTLD-like pathologies in vivo. These data have implications for the diagnosis and care of transplant recipients who are at risk of developing PTLD.

Effect of pre-emptive rituximab on EBV DNA levels and prevention of post-transplant lymphoproliferative disorder in pediatric kidney transplant recipients: A case series from the pediatric nephrology research consortium.

BACKGROUND: There are scant data on the effect of rituximab on EBV DNA levels and prevention of post-transplant lymphoproliferative disorder (PTLD) in pediatric kidney transplant recipients with EBV DNAemia. METHODS: Kidney transplant recipients with EBV DNAemia treated with rituximab to prevent PTLD between 7/1999 and 7/2019 at five pediatric centers were included. Those with confirmed PTLD at the onset of rituximab were excluded. Primary outcomes included percentage change in EBV DNAemia and occurrence of PTLD post rituximab. RESULTS: Twenty-six pediatric kidney transplant recipients were included. Median age at transplant was 4 years (IQR 2.1-10.3). EBV DNA load monitoring by qPCR was performed at 1-3 month intervals. EBV DNAemia onset occurred at a median of 73 days post-transplant (IQR 52-307), followed by DNAemia peak at a median of 268 days (IQR 112-536). Rituximab was administered at a median of 9 days post peak (IQR 0-118). Rituximab regimens varied; median dose 375 mg/m2 (IQR 375-439) weekly for 1-4 doses per course. Following rituximab, EBV DNA load decreased to <10% of baseline at 120 days in 20/26 patients; however, only 30% achieved complete resolution at last follow-up (median 2094 days post-transplant [IQR 1538-3463]). Two (7%) developed PTLD at 915 and 1713 days post rituximab. All recipients had functioning grafts. One death occurred in a child with PTLD following remission due to unrelated reasons. CONCLUSIONS: In the largest pediatric kidney transplant recipient case series with EBV DNAemia given rituximab to prevent PTLD, rituximab achieved a short-term reduction in DNA load; however, recurrent DNAemia is common.