Development Of Post-transplant Lymphoproliferative Disorder Research Articles

Diagnostics of the Epstein-Barr Virus Before and After Lung Transplantation in a Patient With Developing Posttransplant Lymphoproliferative Disease: A Case Report

The most important risk factor for the development of posttransplant lymphoproliferative disorders (PTLD) is Epstein-Barr virus (EBV) infection after transplant. It increases in seronegative EBV recipients from 23% to 50%. The aim of the study was to assess the serologic status of EBV infections (before lung transplant) and the expression of the virus itself after lung transplant in a 25-year-old patient with cystic fibrosis. In a 25-year-old patient with cystic fibrosis, immediately before lung transplant, all diagnostically significant antibodies related to EBV infection were determined in blood serum using enzyme-linked immunosorbent assay methods, using tests by Euroimmun and PerkinElmer Company. Additionally, the organ donor's serologic profile was assessed with the same tests. After lung transplant, the risk of EBV infection was monitored in whole blood and virus expression was determined by reverse transcriptase–polymerase chain reaction with Biomerieux Argene tests. Before lung transplant, the patient was shown to have no antibodies against EBV in both IgM and IgG classes. The constellation of organ donor antibodies clearly indicated a past infection. The presence of EBV virus copies in whole blood was demonstrated in the patient 9 months after transplant. Constant monitoring of the patient and modification of the treatment did not, unfortunately, protect him from the development of PTLD. The obtained results clearly confirm the purposefulness of both serologic and molecular determinations in lung recipients related to EBV. The likelihood of developing PTLD increases both in people who have not had EBV infection and patients with reactivation of the infection.

Reduction of Immunosuppression Based on Whole Blood EBV-Viral Loads in Lung Transplant Recipients

<h3>Purpose</h3> Post-transplant lymphoproliferative disorder (PTLD) is a rare but serious complication of transplantation affecting 10% of lung transplant recipients with an overall survival of 39%. Reduction of immunosuppression (RIS) for clinically suspected PTLD is included in guidelines for the treatment of PTLD. Pre-emptive RIS based on EBV DNA load is controversial with small scale studies with anecdotal evidence guiding clinical practice. We evaluated our policy of pre-emptive RIS for PTLD incidence, acute rejection, survival and CLAD in a patient control study. <h3>Methods</h3> 26 patients underwent RIS, eight of these patients received prophylactic rituximab. 52 patients were matched for age, date of transplantation, gender, and cystic fibrosis. 26 of these patients were additionally chosen for high EBV-DNA load. Risk of PTLD, acute rejection, overall survival and CLAD was analysed using Kaplan-Meier survival analysis. <h3>Results</h3> EBV DNA loads were different between the groups (p<0.001) with the RIS group having the highest level and more primary EBV infections (table 1). Acute rejection was seen 7.3 years after RIS and 11.7 and 12.3 in the matched groups (p=0,1). Overall CLAD developed earlier in the RIS group but only years after RIS (table 1). Survival and development of PTLD were not different between the groups. Time to PTLD from RIS was also not different (p=0.5, log-rank test). <h3>Conclusion</h3> Pre-emptive RIS based on EBV DNA load did not lead to a concomitant increase in acute rejection episodes, a change in overall survival or a short term increase in chronic lung allograft rejection (CLAD) diagnosis. We conclude that RIS was safe although this analysis cannot prove a reduction in the incidence of PTLD in this high risk PTLD group. A prospective randomized study for EBV DNA guided RIS possibly with pre-emptive rituximab is needed.

Presentation and outcomes of post-transplant lymphoproliferative disorder at a single institution pediatric transplant center.

This study aimed to characterize features present at the time of diagnosis and describe outcomes in patients with post-transplant lymphoproliferative disorder (PTLD) following pediatric solid organ transplantation. We performed a retrospective review of solid organ transplant patients who developed pathologically confirmed PTLD at our center from 2006 to 2016. Of 594 patients included in this study, 41(6.9%) were diagnosed with PTLD. Median age at transplant was 5.6(IQR 1.7-16.1) years. Proportion of PTLD cases by organ transplanted and median time (IQR) to disease onset were: heart 11/144(7.6%) at 13.6(8.5-55.6) months, lung 7/52(13.5%) at 9.1(4.9-35) months, kidney 8/255(3.1%) at 39.5(13.9-57.1) months, liver 12/125(9.6%) at 7.7(5.5-22) months, intestine 0/4(0%), and multi-visceral 3/14(21.4%) at 5.4(5.4-5.6) months. No significant correlation was seen between recipient EBV status at transplant and timing of development of PTLD. There were six early lesions, 15 polymorphic, 19monomorphic, and one uncharacterizable PTLD. Following immunosuppression reduction, 30 patients received rituximab, and 14 required chemotherapy. At median 25(IQR 12-53) months follow-up from the onset of PTLD, eight patients died secondary to transplant related complications, three are alive with active disease, and 30have no evidence of disease. PTLD is a significant complication following pediatric solid organ transplantation. EBV levels in conjunction with symptomatic presentation following transplant may assist in detection of PTLD. Most patients can achieve long-term disease-free survival through immunosuppression reduction, anti-CD20 treatment, and chemotherapy in refractory cases.

Nondestructive versus advanced post-transplant lymphoproliferative disorder in a single-center pediatric kidney transplant population.

Pediatric kidney transplant recipients are at risk for the development of post-transplant lymphoproliferative disorders (PTLD), a group of potentially devastating diseases that present on a spectrum of severity ranging from nondestructive PTLD to more histologically destructive lesions. Currently, there is inadequate evidence to guide evaluation and management of nondestructive PTLD. This is a single-center case series of pediatric kidney transplant recipients between January 1, 2008 and December 31, 2019, who were diagnosed with PTLD. The aim was to describe clinical characteristics, presentation, and management of nondestructive versus advanced PTLD. Eighteen patients were diagnosed with nondestructive PTLD and seven with more advanced PTLD histopathology. The majority (66.7%) of nondestructive PTLD patients (n=16) presented with tonsillar hypertrophy and/or snoring and were managed conservatively, with minimal reduction in tacrolimus dose and no further evaluation. No patient progressed to more advanced PTLD. Advanced PTLD patients (n=7) were more likely to present with fever, elevated creatinine, a new mass of gastrointestinal symptoms. They received workup with imaging and oncology consultation, and were managed with chemotherapy. Patients with nondestructive PTLD often present with symptoms of sleep-disordered breathing and can be managed conservatively with excellent clinical outcomes. More study is needed to guide care of this under-researched population.

Role of Cytomegalovirus in the Development of Posttransplant Lymphoproliferative Disorders With or Without Epstein-Barr Virus Infection.

Many studies have revealed the role of Epstein-Barr virus infection, in combination with chronic immunosuppression, as the main factor in the development of posttransplant lymphoproliferative disorder malignancy. Although many studies have been published on other confounding factors involved in posttransplant lymphoproliferative disorders, the role of coinfection with both cytomegalovirus and Epstein-Barr virus has not been investigated. We evaluated the role of cytomegalovirus infection as a risk factor in transplant recipients who were simultaneously infected with Epstein-Barr virus. In the current retrospective study, 143 recipients of various solid-organ transplants at Namazi Hospital from April 2018 to March 2019 were assessed for coinfection with cytomegalovirus and Epstein-Barr virus with the TaqMan real-time polymerase chain reaction assay. We collected clinical and pathology details from their medical records. Of the 143 patients, 81 (57%) were male. Children under 5 years old were the largest group with 32% prevalence, and the most common organ transplant in this study was liver transplant. The prevalence of cytomegalovirus and Epstein-Barr virus coinfection was 12.6% (18/143 patients), of whom 50% experienced posttransplant lymphoproliferative disorder (9/18 patients) during 18 months after transplant. The incidence of posttransplant lymphoproliferative disorder was significantly higher among patients coinfected with cytomegalovirus and Epstein-Barr virus than among patients without coinfection. We observed a significant correlation between cytomegalovirus viral loads, as well as Epstein-Barr virus genome load, in posttransplant lymphoproliferative disorder development. Coinfection with cytomegalovirus and Epstein-Barr virus, as well as the genome load of each virus, can serve as a strong predictive factor of posttransplant lymphoproliferative disorder in solidorgan transplant recipients.

Sirolimus-Based Immunosuppression Is Associated with Decreased Incidence of Post-Transplant Lymphoproliferative Disorder after Heart Transplantation: A Double-Center Study.

Mammalian target of rapamycin (mTOR) inhibitors have been shown to reduce proliferation of lymphoid cells; thus, their use for immunosuppression after heart transplantation (HT) may reduce post-transplant lymphoproliferative disorder (PTLD) risk. This study sought to investigate whether the sirolimus (SRL)-based immunosuppression regimen is associated with a decreased risk of PTLD compared with the calcineurin inhibitor (CNI)-based regimen in HT recipients. We retrospectively analyzed 590 patients who received HTs at two large institutions between 1 June 1988 and 31 December 2014. Cox proportional-hazard modeling was used to examine the association between type of primary immunosuppression and PTLD after adjustment for potential confounders, including Epstein–Barr virus (EBV) status, type of induction therapy, and rejection. Conversion from CNI to SRL as primary immunosuppression occurred in 249 patients (42.2%). During a median follow-up of 6.3 years, 30 patients developed PTLD (5.1%). In a univariate analysis, EBV mismatch was strongly associated with increased risk of PTLD (HR 10.0, 95% CI: 3.8–26.6; p < 0.001), and conversion to SRL was found to be protective against development of PTLD (HR 0.19, 95% CI: 0.04–0.80; p = 0.02). In a multivariable model and after adjusting for EBV mismatch, conversion to SRL remained protective against risk of PTLD compared with continued CNI use (HR 0.12, 95% CI: 0.03–0.55; p = 0.006). In conclusion, SRL-based immunosuppression is associated with lower incidence of PTLD after HT. These findings provide evidence of a benefit from conversion to SRL as maintenance therapy for mitigating the risk of PTLD, particularly among patients at high PTLD risk.

CHRONIC LYMPHOCYTIC LEUKEMIA ARISING IN PATIENT WITH HODGKIN LYMPHOMA TREATED WITH PERIPHERAL BLOOD STEM CELL TRANSPLANTATION -CASE REPORT

Post-transplant lymphoproliferative disorders (PTLDs) are lymphoid or plasmacytic proliferations that develop as a consequence of immunosuppression in a recipient of a solid organ, bone marrow or stem cell allograft. The development of PTLDs is usually associated with Epstein-Barr virus (EBV) and the disorder is also termed EBV-associated lymphoproliferative disorder (LPD). The development of PTLD is a rare complication in autologous bone marrow/peripheral blood stem cell transplantation. In the present study, we report a case of&nbsp;&nbsp; LPD which developed following autologous peripheral blood stem cell transplantation for relapsing Hodgkin's lymphoma. Keywords: CLL, post-transplant lymphoproliferative disorders, Covid 19. &nbsp;

Effect of preoperative long-term use of corticosteroids on the development of post-transplant lymphoproliferative disorders after lung transplantation: a single-center experience in Japan.

Post-transplant lymphoproliferative disorder (PTLD) is a major complication of lung transplantation (LTx). However, few studies on PTLD in Asian populations have been reported. We explored the characteristics of Japanese PTLD cases after LTx. We retrospectively reviewed 195 cases of LTx at our institute. We summarized the clinical experiences of 7 PTLD cases and analyzed the patient characteristics and survival outcomes of patients with (n = 7) and without (n = 188) PTLD. All PTLD patients were taking corticosteroids preoperatively (p = 0.0030), and the duration of preoperative corticosteroid therapy was significantly longer in the PTLD group (p = 0.0064) than in the non-PTLD group. The overall survival after LTx was significantly worse in the PTLD group (p = 0.027) than in the non-PLTD group. Among the three patients who died within 1year after the PTLD onset, two died of opportunistic infections without residual PTLD lesions. Chronic lung allograft dysfunction (CLAD) or bronchiolitis obliterans at an autopsy were diagnosed after PTLD treatment in four cases. Long-term preoperative corticosteroid therapy may be a risk factor for PTLD after LTx. Opportunistic infections are lethal complications of PTLD, regardless of the effectiveness of PTLD treatment. CLAD occurs at a high rate after PTLD treatment, and close monitoring is required.

Validation of a Post-Transplant Lymphoproliferative Disorder Risk Prediction Score and Derivation of a New Prediction Score Using a National Bone Marrow Transplant Registry Database.

We externally validated Fujimoto's post-transplant lymphoproliferative disorder (PTLD) scoring system for risk prediction by using the Taiwan Blood and Marrow Transplant Registry Database (TBMTRD) and aimed to create a superior scoring system using machine learning methods. Consecutive allogeneic hematopoietic cell transplant (HCT) recipients registered in the TBMTRD from 2009 to 2018 were included in this study. The Fujimoto PTLD score was calculated for each patient. The machine learning algorithm, least absolute shrinkage and selection operator (LASSO), was used to construct a new score system, which was validated using the fivefold cross-validation method. We identified 2,148 allogeneic HCT recipients, of which 57 (2.65%) developed PTLD in the TBMTRD. In this population, the probabilities for PTLD development by Fujimoto score at 5 years for patients in the low-, intermediate-, high-, and very-high-risk groups were 1.15%, 3.06%, 4.09%, and 8.97%, respectively. The score model had acceptable discrimination with a C-statistic of 0.65 and a near-perfect moderate calibration curve (HL test p = .81). Using LASSO regression analysis, a four-risk group model was constructed, and the new model showed better discrimination in the validation cohort when compared with The Fujimoto PTLD score (C-statistic: 0.75 vs. 0.65). Our study demonstrated a more comprehensive model when compared with Fujimoto's PTLD scoring system, which included additional predictors identified through machine learning that may have enhanced discrimination. The widespread use of this promising tool for risk stratification of patients receiving HCT allows identification of high-risk patients that may benefit from preemptive treatment for PTLD. This study validated the Fujimoto score for the prediction of post-transplant lymphoproliferative disorder (PTLD) development following hematopoietic cell transplant (HCT) in an external, independent, and nationally representative population. This study also developed a more comprehensive model with enhanced discrimination for better risk stratification of patients receiving HCT, potentially changing clinical managements in certain risk groups. Previously unreported risk factors associated with the development of PTLD after HCT were identified using the machine learning algorithm, least absolute shrinkage and selection operator, including pre-HCT medical history of mechanical ventilation and the chemotherapy agents used in conditioning regimen.

Epstein-Barr Virus Predicts Malignancy After Pediatric Heart Transplant, Induction Therapy and Tacrolimus Don’t

BackgroundPatients after heart transplantation are at increased risk for malignancy secondary to immunosuppression and oncogenic viral infections. Most common among children is posttransplant lymphoproliferative disorder (PTLD), occurring in 5% to 10% of patients. We used a national database to examine the incidence and risk factors for posttransplant malignancy. MethodsThe United Network for Organ Sharing database was queried for pediatric (<18 years) heart transplant recipients from October 1987 through November 2019. Freedom from malignancy after transplant was assessed with Kaplan-Meier analysis. Cox regression was performed to generate hazard ratios (HRs) and 95% CIs for risk of malignancy development. ResultsOf 8581 pediatric heart transplant recipients, malignancy developed in 8.1% over median follow-up time of 6.3 years, with PTLD compromising 86.4% of the diagnosed cancers. The incidence of PTLD development was 1.3% at 1 year and 4.5% at 5 years. Older age at the time of transplant was protective against the development of malignancy (HR, 0.98; 95% CI, 0.96-0.99; P < .001), whereas a history of previous malignancy (HR, 1.9; 95% CI, 1.2-3.0; P = .007) and Ebstein-Barr virus (EBV) recipient-donor mismatch (HR, 1.7; 95% CI, 1.3-2.2; P < .001) increased the risk. Induction therapy, used in 78.9% of the cohort, did not increase malignancy risk (P = .355) nor did use of maintenance tacrolimus (P = .912). ConclusionsPTLD occurred after 7% of pediatric heart transplants, with risk increased by younger age and EBV mismatch, highlighting the importance of PTLD monitoring in EBV-seronegative recipients. Induction therapy, used in most of the pediatric heart transplants, does not seem to increase posttransplant malignancy nor does tacrolimus, the most commonly used calcineurin inhibitor.

Posttransplant Lymphoproliferative Disorder Status Post-Solid Organ Transplant Presenting to the Emergency Department: Single Institute Experience.

The objective of this study was to evaluate the clinical, laboratory, imaging, and pathology findings associated with emergency department presentations of posttransplant lymphoproliferative disorder (PTLD) after solid organ transplant (SOT). Fifteen patients presenting to a single tertiary care center between 2004 and 2019 with PTLD after SOT were identified from a pathology database. Twelve patients presenting through the emergency department were included in the study. Demographic, clinical, imaging, pathology, treatment, and outcome data were reviewed. Among this 12 patient cohort (7 men; mean age, 44.2 years), transplant history included 4 combined kidney/pancreas, 4 kidney, 2 liver, 1 cardiac, and 1 lung. Mean time from transplant to diagnosis was 7.6 years. Posttransplant lymphoproliferative disorder was identified on initial computed tomography scans in 10 of 12 patients. The most common sites for PTLD development were the gastrointestinal tract (4/12) and liver (3/12). Outcomes included resolution of PTLD in 9 of 12 patients, with 3 patients dying within 6 months of diagnosis. Posttransplant lymphoproliferative disorder is a serious consequence of solid organ transplantation that can present in various locations and with varied symptomatology in the emergency setting. Other posttransplant complications may present similarly including chronic rejection and infection. Posttransplant lymphoproliferative disorder should be considered in SOT patients presenting with worsening abdominal pain or constitutional symptoms, even with normal laboratory workup.

Incidence and Risk Factors of Epstein-Barr Virus Viremia in Patients Undergoing Haploidential Transplantation with Post Translant Cyclophosphamide

INTRODUCTIONHaploidentical stem cell transplants are increasingly performed for a wide variety of malignant and non-malignant hematological conditions. Epstein - Barr virus (EBV) viremia and subsequent development of Post-Transplant Lymphoproliferative Disorder (PTLD) are potential adverse sequelae of the transplantation process and associated immunosuppression. Traditionally, haploidentical transplants have been associated with increased risk of EBV reactivation and subsequent PTLD. This was largely due to graft versus host disease (GVHD) prophylaxis protocols using intense immunosuppression with either Ex-vivo T-cell depletion or in-vivo T- cell depletion with anti-thymocyte globulin (ATG) and Alemtuzumab. However, most haploidentical transplants in recent years have utilized post-transplant cyclophosphamide (PTCy) for GVHD prophylaxis. Rituximab has been used for preemptive treatment of EBV viremia/PTLD, but there is scarce data on its use in this setting, as well as the risk factors and outcomes of EBV viremia associated with haploidentical transplants with PTCy. RESULTSA total of 63 patients with hematological malignancies received haploidentical transplant at our institution from 2013 from 2016. Patient characteristics are summarized in Table 1.All patients received EBV monitoring using plasma viral copies once weekly starting 20 days post-transplant. EBV monitoring continued for 6 months after immunosuppression ended or when CD4 count >200. Among these 63 patients, 18 (28.5%) became EBV DNA positive upon follow-up. Per institutional protocol, EBV titer was confirmed by repeat testing when viral load was 1000 copies/mL and treatment with Rituximab was initiated if repeat titer was >1000 copies/ml.The median time to detection of EBV viremia from the time of transplant was 99 days (range: 20-277). The median peak level for the EBV reactivation cohort was 7650 viral copies /ml. The median time from detection of viremia to peak viremia was 1.5 days (range 0-253).8 of the 18 (44.4%) patients that developed EBV viremia required Rituximab due to rising or persistent EBV viremia. The median EBV level at initiation of therapy was 31,000 copies/ml for the 8 patients that received Rituximab treatment. EBV seronegativity was achieved in 6 patients (75%) with treatment at a median of 13.5 days (range 3-26). The median number of Rituximab cycles administered was 1.5 (range: 1-16). None of the patients in either cohort developed PTLD or other EBV associated diseases.A univariate analysis was performed comparing EBV reactivation cohort and no EBV reactivation cohort to look for risk factors predisposing to EBV reactivation (Table 1) There were no statistically significant differences seen in the variables studied other than patients not in complete remission at the time of transplant were statistically more likely to develop EBV viremia. 9 out of 18 patients (50%) that developed EBV viremia were not in complete remission at the time of transplant, whereas 11 out of the 45 patients (24.44 %) that did not develop EBV viremia were in an incomplete remission at the time of transplant (p value: 0.05) (Table 1).With a median follow up of469 days, there were a total of 22 deaths among the 45 (48.9 %) patients that had no viremia, and 8 deaths amongst the 18 (44.4 %) patients that had viremia (p value: 0.75). There was no statistically significant difference in graft versus host disease (GVHD) incidence (p value: 0.79) or overall survival (555 days for patients with EBV reactivation versus not reached for patients without EBV reactivation, p value: 0.45) between these two groups (p value: 0.79) CONCLUSIONSIn this retrospective study assessing risk factors and outcomes of EBV viremia in patients following haploidentical transplants, we observed a 28.5 percent incidence of EBV viremia. Rituximab was effective in preemptive treatment of EBV viremia. However, no cases of PTLD were observed, even in those patients with sustained elevation in EBV titers. It is unclear how to manage asymptomatic elevations in viral titers after allogeneic transplantation in patients who are otherwise at low risk for development of PTLD. Previous data suggests that even high levels of EBV viremia lacks specificity for prediction of PTLD in post-transplant setting. Given these results, the utility of routine monitoring of EBV viral load after haploidentical transplant should be questioned in those who have received PTCy. [Display omitted] DisclosuresLin:Jazz Pharmaceuticals: Consultancy. Ganguly:Amgen: Other: Advisory Board; Seattle Genetics: Speakers Bureau.

A systematic review of post-transplant lymphoproliferative disorder after renal transplantation.

e19577 Background: Post Transplant Lymphoproliferative Disorder (PTLD) is a rare but severe complication following renal transplant. This study aims to explore the treatment modalities, histological types, and risk factors related to PTLD. Methods: Following the PRISMA guideline, we searched the literature on PubMed, Cochrane, Embase &amp; clinicaltrials.gov. A total of 1741 articles were screened and 16 studies were included. Results: We reviewed 275915 adult patients who underwent renal transplantation out of which 2484 (0.9%) patients developed PTLD. Data for gender shows that 61.1% were males and 38.9% females. 576/2484 (23%) cases were EBV positive post-transplant. Seven studies showed the median duration from transplant to the development of PTLD was 80 months (5m-22yrs). Monomorphic PTLD was reported in 585 cases as the most common histological type. 5 studies suggested mortality due to PTLD was 41.38%. OS at 5 and 10 years was 55% and 41% respectively. Conclusions: Our study shows that PTLD is a rare complication after renal transplant which was more common in males. EBV did not show association with PTLD. Monomorphic is the most common histological type of PTLD after renal transplant. Our results show that it is associated with significantly high mortality. [Table: see text]

A systematic review of post-transplant lymphoproliferative disorder after liver transplant.

e19045 Background: Post-transplant lymphoproliferative disorder (PTLD) is a complication after liver transplantation. This study aims to explore the association of PTLD with the immunosuppression, types of PTLD, clinical presentation, and outcomes. Methods: Following the PRISMA guideline, we searched the literature on PubMed, Cochrane, Embase, and clinicaltrials.gov. 1741 articles were screened and 22 studies were included. Results: Data includes 22,235 total patients who underwent a liver transplant, and 449 (2.0%) patients who developed PTLD were studied. Of the 394 patients where gender was reported, 226 were male and 168 were female. Post-transplant EBV status was positive for 63/115 (56%). 11 studies showed that the median time from transplant to the development of PTLD was 33.4 months. Among the histological types of PTLD, the monomorphic B-cell was the most common type with 127/235 (54%) cases, followed by early lesions 25/235, polymorphic 24/235, Hodgkin lymphoma 8/235, and monomorphic T-cell type 7/235. Treatment of PTLD involved reduction or cessation of the immunosuppressive drugs along with chemotherapy surgery and radiotherapy. Mortality data from 13 studies showed 68/259 (31.3%) patients died either due to PTLD or its complication. Conclusions: PTLD is rare but associated with high mortality after liver transplantation. EBV seropositivity is associated with PTLD in the majority of cases. Monomorphic PTLD is the most common type of PTLD after liver transplantation with DLBCL being the most common subtype. Abdominal symptoms and fever are among the most common symptoms. PTLD after Liver transplant a review of studies. [Table: see text]

Prior antithymocyte globulin therapy and survival in post-transplant lymphoproliferative disorders

Background: Treatment with antithymocyte globulin (ATG) is a well-recognized risk factor for the development of post-transplant lymphoproliferative disorders (PTLD) after solid organ transplantation, but it is unknown how its use affects overall survival after PTLD. Methods: A total of 114 patients with PTLD and available data on immunosuppressive regimen were included from a nation-wide case series of solid organ transplant recipients in Sweden. Prior use of ATG was correlated to clinical features, PTLD subtype, and survival. Results: A total of 47 (41%) patients had received ATG prior to the diagnosis of PTLD. The ATG-treated patients were more likely to be recipients of hearts or lungs, and less likely of kidneys (p < 0.01). They had experienced more acute rejections (p = 0.02). The PTLDs arose earlier, median 2.0 vs. 6.6 years post-transplant (p = 0.002) and were more often situated in the allograft (32% vs. 7%, p < 0.001) in patients with prior ATG vs. no ATG treatment. The PTLDs in the ATG group were more often Epstein–Barr virus-positive (80% vs. 40%, p < 0.001). There were more polymorphic PTLDs (17% vs. 1.5%, p = 0.004) and less T-cell PTLDs (4% vs. 19%, p = 0.02) in the ATG group than in the no ATG group. Diffuse large B-cell lymphoma was equally common in patients with and without prior ATG therapy, but the non-germinal center subtype was more frequent in the ATG group (p = 0.001). In an adjusted Cox proportional hazards regression model, prior ATG treatment and better performance status were associated with superior overall survival, whereas older age, T-cell subtype of PTLD, presence of B symptoms, and elevated lactate dehydrogenase were associated with inferior overall survival. Patients receiving ATG solely as rejection therapy had superior overall survival compared with those receiving ATG as induction therapy or both (p = 0.03). Conclusions: ATG therapy, especially rejection therapy, prior to PTLD development is an independent prognostic factor for superior overall survival after PTLD diagnosis.

High numbers of programmed cell death-1-positive tumor infiltrating lymphocytes correlate with early onset of post-transplant lymphoproliferative disorder.

Post-transplant lymphoproliferative disorder (PTLD) is a life-threatening complication of transplantation. In addition to reactivation of Epstein-Barr virus in immunocompromised patients, impaired tumor immunity is suggested to be a risk factor for PTLD. However, it remains unclear whether immune suppressive tumor-infiltrating lymphocytes (TILs) correlate with the occurrence or prognosis of PTLD. We analyzed TILs in 26 patients with PTLD to elucidate the clinicopathological significance of the expression of PD-1 and FoxP3, which are associated with exhausted T-cells and regulatory T-cells (Tregs), respectively. Numbers of PD-1+ TILs in the PTLD specimens were significantly higher in patients who developed PTLD early after transplantation (P = 0.0040), while numbers of FoxP3+ TILs were not (P = 0.184). There was no difference in overall response rate regardless of the expression of PD-1 or FoxP3. FoxP3high patients tended to have a shorter time to progression compared with FoxP3low patients, especially in the case of FoxP3high patients with diffuse large B-cell lymphoma-subtype PTLD (P = 0.011), while PD-1high patients did not. These results suggest that T-cell exhaustion may be mainly associated with PTLD development, while immune suppression by Tregs may be dominant in enhanced progression of PTLD following disease occurrence.

Identification of Epstein-Barr Virus Related Risk Factors for the Occurrence of Post-Transplant Lymphoproliferative Disorder in Lung Transplant Recipients

<h3>Purpose</h3> Post-transplant lymphoproliferative disorder (PTLD) is the second most common malignancy in solid organ transplantation. Based on recent registry data, ≈ 1.1% of lung transplants (LTx) develop PTLD within the first year. PTLD confers significant morbidity and mortality and has been associated with Epstein-Barr virus (EBV) infection. The threshold for EBV viremia predictive of PTLD is unknown. In the current study we examined risk factors for PTLD development and the relationship between EBV viremia and PTLD in LTx was assessed. <h3>Methods</h3> A single-center, retrospective review of all LTx recipients from 1/1/2009 - 7/31/2019 with EBV viremia was conducted. All patients (pts) with at least one positive EBV PCR test were reviewed for EBV viremia progression and PTLD occurrence. PTLD was confirmed by review of oncology notes, biopsy results, computed tomography and positron emission tomography scans. <h3>Results</h3> One hundred and forty-seven pts were included. Thirty-four (24.8%) underwent work-up for PTLD, of whom ten were diagnosed with PTLD. Median time from transplant to EBV viremia was 368 days (IQR 111-1201) with PTLD diagnosis occurring at a median of 521 days (IQR 150-741) after LTx. The PTLD(+) group had a higher baseline median EBV PCR of 2613 copies/mL (IQR 680-6099) vs 528 copies/mL (IQR 369-930) in PTLD(-) pts and an increased number of positive PCRs; 3.5 (IQR 2-10) vs 1 (IQR 1-2). In patients with EBV IgG data available, (<i>n</i>=66), Donor(+)/Recipient(-) pts were more likely to develop PTLD than other groups, RR = 18.3 (95% CI 3.93, 85.32); p<0.001. A cut-point analysis of EBV viral load determined that pts with a baseline EBV viral load >1930 copies/mL had a significantly higher risk of PTLD development, RR = 31.03 (95 %CI 9.44, 102.02); p<0.001. <h3>Conclusion</h3> EBV mismatch, higher viral loads, and persistence of viremia may be indicative of PTLD development. Patients with an EBV viral load >1930 copies/ml may benefit from closer surveillance.

PD-1 Blockade Aggravates Epstein-Barr Virus+ Post-Transplant Lymphoproliferative Disorder in Humanized Mice Resulting in Central Nervous System Involvement and CD4+ T Cell Dysregulations.

Post-transplant lymphoproliferative disorder (PTLD) is one of the most common malignancies after solid organ or allogeneic stem cell transplantation. Most PTLD cases are B cell neoplasias carrying Epstein-Barr virus (EBV). A therapeutic approach is reduction of immunosuppression to allow T cells to develop and combat EBV. If this is not effective, approaches include immunotherapies such as monoclonal antibodies targeting CD20 and adoptive T cells. Immune checkpoint inhibition (ICI) to treat EBV+ PTLD was not established clinically due to the risks of organ rejection and graft-versus-host disease. Previously, blockade of the programmed death receptor (PD)-1 by a monoclonal antibody (mAb) during ex vivo infection of mononuclear cells with the EBV/M81+ strain showed lower xenografted lymphoma development in mice. Subsequently, fully humanized mice infected with the EBV/B95-8 strain and treated in vivo with a PD-1 blocking mAb showed aggravation of PTLD and lymphoma development. Here, we evaluated vis-a-vis in fully humanized mice after EBV/B95-8 or EBV/M81 infections the effects of a clinically used PD-1 blocker. Fifteen to 17 weeks after human CD34+ stem cell transplantation, Nod.Rag.Gamma mice were infected with two types of EBV laboratory strains expressing firefly luciferase. Dynamic optical imaging analyses showed systemic EBV infections and this triggered vigorous human CD8+ T cell expansion. Pembrolizumab administered from 2 to 5 weeks post-infections significantly aggravated EBV systemic spread and, for the M81 model, significantly increased the mortality of mice. ICI promoted Ki67+CD30+CD20+EBER+PD-L1+ PTLD with central nervous system (CNS) involvement, mirroring EBV+ CNS PTLD in humans. PD-1 blockade was associated with lower frequencies of circulating T cells in blood and with a profound collapse of CD4+ T cells in lymphatic tissues. Mice treated with pembrolizumab showed an escalation of exhausted T cells expressing TIM-3, and LAG-3 in tissues, higher levels of several human cytokines in plasma and high densities of FoxP3+ regulatory CD4+ and CD8+ T cells in the tumor microenvironment. We conclude that PD-1 blockade during acute EBV infections driving strong CD8+ T cell priming decompensates T cell development towards immunosuppression. Given the variety of preclinical models available, our models conferred a cautionary note indicating that PD-1 blockade aggravated the progression of EBV+ PTLD.

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

Background: Post-transplant lymphoproliferative disorder (PTLD) is a B-cell proliferation disorder that results from disruption in the physiological mechanisms for proliferation in an immunocompromised host after a solid organ transplant. Our study aims to review the demographic characteristics and clinical outcomes after transplantation. We also aim to study the role of immunosuppression induction therapy, the effect of PTLD on survival, and the effective chemotherapy used for B-cell disorders leading to improved survival. Methods: Following the PRISMA guideline, we performed a comprehensive literature search on PubMed, Cochrane Library, Embase, and clinicaltrials.gov from the past decade on May 04, 2020. We used the MeSH terms of organ transplantation and lymphoproliferative disorders. 1741 articles were screened. We excluded all case reports, case series, pre-clinical trials, review articles, and meta-analysis and included three cohort studies and one prospective multicentric study. We extracted the data for baseline characteristics, the reason for transplantation, recipient &amp; donor EBV status, immunosuppression used, type &amp; stage of PTLD, organ system involved, duration between transplant and PTLD diagnosis, treatment, response to therapy, adverse effects of therapy and mortality. Results: We studied 9617 patients in the included four studies, out of which 499 patients developed PTLD. Data in these studies was collected over the last 20-26 years. Median follow-up of patients since transplant was 3-9 years (average 7.5y). Table 1 The age of the patients ranged from 3-18 years with a male: female gender ratio of 48:52% and around 50% of the patients were seronegative to EBV pretransplant. The following drugs were used for immunosuppression: cyclosporin, tacrolimus, azathioprine, mycophenolate, interleukin 2 receptor antagonist (basiliximab), corticosteroids, anti-thymocyte globulins(ATG). Kindel et al. narrated that the development of eosinophilic oesophagitis may be a marker for the development of PTLD.Gajarski et al. concluded that Post-transplant Immunosuppressive induction therapy with cytolytic drugs (e.g OKT3 monoclonal antibody, ATG, thymoglobulin Basiliximab and daclizumab) , lowers the rate of PTLD, graft rejections, and early infections in post-transplant patients as compared patients who did not receive induction therapy . This depends upon the type of induction e.g OKT3 monoclonal antibody was associated with increased PTLDs and graft rejection, while Thymoglobulin/IL-2R antagonists demonstrated to decrease both the outcomes. Claire et al. described that overall mortality is decreasing due to the ongoing better understanding of pathophysiology and treatment options related to solid organ transplant. The mortality of the post-transplant congenital heart disease group was higher as compared to the cardiomyopathy group due to high comorbidities and surgical complications. The study by Christopher et al. showed that EBV seronegativity before transplant is associated with an increased risk of PTLD. PTLD is associated with lower survival rates as compared to non-PTLD groups. Conclusion: Our review illustrates that pretransplant seronegativity, OKT3 monoclonal antibody, and the development of eosinophilic esophagitis during the immunosuppressive regime increase the risk of PTLD. This study demonstrates that with a better understanding of PTLD and tumor behavior, the all-cause mortality rates are falling significantly. PTLD is one of the leading causes of mortality in post-transplant patients. However, the immunosuppressive induction therapy, absence of eosinophilic esophagitis, thymoglobulin/IL-2R antagonists improve survival and outcomes in the post-transplant patient in terms of graft rejection, graft failure, and development of PTLD. Disclosures Anwer: Incyte, Seattle Genetics, Acetylon Pharmaceuticals, AbbVie Pharma, Astellas Pharma, Celegene, Millennium Pharmaceuticals.: Honoraria, Research Funding, Speakers Bureau.

Co-infection of Cytomegalovirus and Epstein-Barr Virus Diminishes the Frequency of CD56dimNKG2A+KIR- NK Cells and Contributes to Suboptimal Control of EBV in Immunosuppressed Children With Post-transplant Lymphoproliferative Disorder.

Post-transplant lymphoproliferative disorder (PTLD) is a rare but potentially life-threatening complication, frequently associated with Epstein-Barr virus (EBV), which develops after solid organ or stem cell transplantation. Immunosuppression received by transplant recipients has a significant impact on the development of PTLD by suppressing the function of T cells. The preferential proliferation of NKG2A-positive natural killer (NK) cells during primary symptomatic EBV infection known as infectious mononucleosis (IM) and their reactivity toward EBV-infected B cells point to a role of NK cell in the immune control of EBV. However, NK cell-mediated immune response to EBV in immunosuppressed transplant recipients who develop PTLD remains unclear. In this study, we longitudinally analyzed the phenotype and function of different NK cell subsets in a cohort of pediatric liver transplant patients who develop PTLD and compared them to those of children with IM. We found persistently elevated plasma EBV DNA levels in the PTLD patients indicating suboptimal anti-viral immune control. PTLD patients had markedly decreased frequency of CD56dimNKG2A+Killer Immunoglobulin-like receptor (KIR)− NK cells from the time of diagnosis through remission compared to those of IM patients. Whilst the proliferation of CD56dimNKG2A+KIR− NK cells was diminished in PTLD patients, this NK cell subset maintained its ability to potently degranulate against EBV-infected B cells. Compared to cytomegalovirus (CMV)-seropositive and -negative IM patients, PTLD patients co-infected with CMV and EBV had significantly higher levels of a CMV-associated CD56dimNKG2ChiCD57+NKG2A−KIR+ NK cell subset accumulating at the expense of NKG2A+KIR− NK cells. Taken together, our data indicate that co-infection of CMV and EBV diminishes the frequency of CD56dimNKG2A+KIR− NK cells and contributes to suboptimal control of EBV in immunosuppressed children with PTLD.