EBV-associated Post-transplant Lymphoproliferative Disorder Research Articles

Chronic Epstein-Barr viral load carriage after pediatric organ transplantation.

Epstein-Barr virus (EBV) infection and EBV-associated post-transplant lymphoproliferative disorder (EBV/PTLD) is one of the most devastating complications occurring in pediatric solid organ transplant (SOT) recipients. Observations of SOT recipients undergoing serial EBV monitoring to inform reduction of immune suppression to prevent EBV-/PTLD has identified patients who maintain chronic high EBV load (CHL) in their blood. The CHL carrier state has been seen more commonly in pediatric compared to adult transplant recipients. Some but not all CHL may progress to EBV/PTLD. However, little is known regarding the biology of this CHL carrier state and the optimal clinical approach to CHL has not been established. This review summarizes the current knowledge and evidence of chronic high EBV load and introduces commonly adopted approaches from experts in this field.

The inhibition of IRE1alpha/XBP1 axis prevents EBV-driven lymphomagenesis in NSG mice.

The novelty of this study lies in the fact that it shows that IRE1 alpha endoribonuclease inhibition by 4μ8C was able to counteract Epstein-Barr virus-driven lymphomagenesis in NOD SCID gamma mice and prevent B-cell immortalization in vitro, unveiling that this drug may be a promising therapeutic approach to reduce the risk of post-transplant lymphoproliferative disorders (PTLD) onset in immune-deficient patients. This hypothesis is further supported by the fact that 4μ8C impaired the survival of PTLD-like cells derived from mice, meaning that it could be helpful also in the case in which there is the possibility that these malignancies have begun to arise.

Host microRNAs are decreased in pediatric solid-organ transplant recipients during EBV+ Post-transplant Lymphoproliferative Disorder.

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation. Predisposing factors include primary Epstein-Barr virus (EBV) infection, reactivation of EBV in recipient B cells, and decreased T cell immunity due to immunosuppression. In our previous studies EBV infection was demonstrated to markedly alter the expression of host B cell microRNA (miR). Specifically, miR-194 expression was uniquely suppressed in EBV+ B cell lines from PTLD patients and the 3’untranslated region of IL-10 was determined to be targeted by miR-194. Although EBV has been shown to regulate host miR expression in B cell lymphoma cell lines, the expression of miRs in the circulation of patients with EBV-associated PTLD has not been studied. The objective of this study was to determine if changes in miR expression are associated with EBV+ PTLD. In this study, we have shown that miR-194 is significantly decreased in EBV+PTLD tumors and that additional miRs, including miRs-17, 19 and 106a are also reduced in EBV+PTLD as compared to EBV-PTLD. We quantitated the levels of miRs-17, 19, 106a, 155, and 194 in the plasma and extracellular vesicles (EV; 50-70 nm as determined by nanoparticle tracking analysis) from pediatric recipients of solid organ transplants with EBV+ PTLD+ that were matched 1:2 with EBV+ PTLD- pediatric transplant recipients as part of the NIH-sponsored Clinical Trials in Organ Transplantation in Children, (CTOTC-06) study. Levels of miRs-17, 19, 106a, and 194 were reduced in the plasma and extracellular vesicles (EV) of EBV+ PTLD+ group compared to matched controls, with miRs-17 (p = 0.034; plasma), miRs-19 (p = 0.029; EV) and miR-106a (p = 0.007; plasma and EV) being significantly reduced. Similar levels of miR-155 were detected in the plasma and EV of all pediatric SOT recipients. Importantly, ~90% of the cell-free miR were contained within the EV supporting that EBV+ PTLD tumor miR are detected in the circulation and suggesting that EVs, containing miRs, may have the potential to target and regulate cells of the immune system. Further development of diagnostic, mechanistic and potential therapeutic uses of the miRs in PTLD is warranted.

In vitro and in vivo evidence that the switch from calcineurin to mTOR inhibitors may be a strategy for immunosuppression in Epstein–Barr virus–associated post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder is a life-threatening complication of immunosuppression following transplantation mediated by failure of T cells to control Epstein-Barr virus (EBV)-infected and transformed B cells. Typically, a modification or reduction of immunosuppression is recommended, but insufficiently defined thus far. In order to help delineate this, we characterized EBV-antigen-specific T cells and lymphoblastoid cell lines from healthy donors and in patients with a kidney transplant in the absence or presence of the standard immunosuppressants tacrolimus, cyclosporin A, prednisolone, rapamycin, and mycophenolic acid. Phenotypes of lymphoblastoid cell-lines and T cells, T cell-receptor-repertoire diversity, and T-cell reactivity upon co-culture with autologous lymphoblastoid cell lines were analyzed. Rapamycin and mycophenolic acid inhibited lymphoblastoid cell-line proliferation. T cells treated with prednisolone and rapamycin showed nearly normal cytokine production. Proliferation and the viability of T cells were decreased by mycophenolic acid, while tacrolimus and cyclosporin A were strong suppressors of T-cell function including their killing activity. Overall, our study provides a basis for the clinical decision for the modification and reduction of immunosuppression and adds information to the complex balance of maintaining anti-viral immunity while preventing acute rejection. Thus, an immunosuppressive regime based on mTOR inhibition and reduced or withdrawn calcineurin inhibitors could be a promising strategy for patients with increased risk of or manifested EBV-associated post-transplant lymphoproliferative disorder.

Epstein-Barr virus status and immunosuppression use in paediatric autoimmune liver disease.

Since azathioprine is associated with lymphoproliferative disorders in Epstein-Barr virus (EBV)-naïve patients with inflammatory bowel disease, guidelines advise avoidance. No recommendations exist for autoimmune liver disease (AILD). To evaluate EBV status and EBV-related complications in paediatric AILD. Single-centre, retrospective, observational study of paediatric AILD. In 245 paediatric patients with AILD, azathioprine was used in 168 (68.6%) and mycophenolate mofetil in 69 (28.2%). EBV status was assessed in 18 (10.7%) prior to azathioprine and 6 (8.7%) MMF. Acute EBV infection was diagnosed in five patients while on immunosuppression, resulting in one transient hepatitis and one persistent hepatitis. There were no cases of lymphoproliferative disorder in native livers. Liver transplantation (LT) was performed in 39 (15.9%) patients, with 8 EBV IgG-negative at LT. Post-LT EBV viraemia developed in 29 (74.4%), first detected at median 26days (IQR, 13-86). EBV IgG-negative recipients had higher peak viraemia (266984IU/mL [IQR, 41108-2429050] v 5333 [IQR, 2036-38770], P=.004) and longer time to peak viraemia (375days [IQR, 251-884] v 70 [IQR, 21-604], P=.04). Early EBV-associated post-transplant lymphoproliferative disorder (PTLD) was diagnosed in two patients, both EBV-IgG negative with prior azathioprine. Real-world data demonstrate that EBV serostatus is not routinely checked before immunosuppression for paediatric AILD. Lymphoproliferative disorder was not diagnosed in those with native livers; however, EBV IgG-negative LT recipients receiving EBV IgG-positive donor organs are at risk of early PTLD. Large multicentre studies with longer follow-up are required to further evaluate the risk.

Acute Epstein‐Barr virus associated haemophagocytosis in an Asian female: What is the diagnosis?

Acute <scp>Epstein‐Barr</scp> virus associated haemophagocytosis in an Asian female: What is the diagnosis?

Chapter XX Antiviral Treatment and Cancer Control.

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papilloma virus (HPV), Epstein-Barr virus (EBV), human T-cell lymphotropic virus type 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), and Merkel cell polyomavirus (MCV) contribute to about 10-15% global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infection have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, KSHV, and HTLV-1 had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA interference-based therapies for treating HPV-associated infection or cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies in a real-world setting are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

Peripheral Blood Monoclonal B-Cell and/or Plasma Cell Detection By Flow Cytometry in Screening and Monitoring EBV-Positive Post-Transplant Lymphoproliferative Disorders

Background Post-transplant lymphoproliferative disorder (PTLD) is a serious complication that can occur following an allogenic hematopoietic stem cell transplant (allo-HSCT). PTLD occurs in approximately 0.8% to 20% of patients following an allo-HSCT and is associated with Epstein-Barr virus (EBV) infection in about 60% to 80% of patients. EBV positive (EBV+) PTLD generally arises early, several months following transplantation. The routine methods to diagnose EBV+ PTLD are clinical symptoms, EBV copy number, imageological examination, and pathological diagnosis, of which pathological diagnosis is the gold standard. Yet obtaining a biopsy is not possible with some patients and is not applicable for post-therapy monitoring. Therefore, there is an urgent need to find a simple, highly efficient, feasible, sensitive, and specific diagnostic and monitoring tool. Flow cytometry (FCM) has been established as a highly cost-effective method to diagnose lymphoma over the past several decades, and particularly for screening monoclonal B and/or plasma cells (MC B/P). Several recent publications as well as our own published and unpublished data have found that MC B/P are present in the peripheral blood of most PTLD patients. To this end, FCM detection of MC B/P in PB is a promising screening and monitoring method for EBV(+) PTLD. Objective To investigate the effectiveness of detecting MC B/P in PB by FCM for EBV+ PTLD screening and monitoring. Methods A total of 1470 patients received allo-HSCT at the Hebei Yanda Ludaopei Hospital, China from January 2018 through December 2019. We conducted a retrospective study of 481 patients with fever and lymphadenopathy following allo-HSCT. Patient PB was extracted for FCM MC B/P analysis. Plasma EBV viral loads were detected by PCR. The median fellow-up time was 6 months (range: 2 days to 21 months). The relationships of PB MC B/P, EBV load and clinical EBV-associated PTLD symptoms were investigated. Results: MC B/Ps were detected in the PB of 47 patients, of which 29 cases had monoclonal B cells, 14 cases had detectable co-existence of monoclonal B cells and monoclonal plasma cells, and 4 cases had detectable monoclonal plasma cells. The median time to PTLD onset following allo-HSCT was 70 days (range: 33 days to 491 days). The median percentage of monoclonal B cells was 0.43% (range: 0.1% to 23.41%. The median percentage of monoclonal plasma cells was 0.25%). Forty of 47 patients (85.1%) were finally diagnosed with PTLD using clinical comprehensive examination of symptoms. The incidence of clinical EBV+ PTLD was 2.9% (44 of 1470 cases). By FCM, MC B/Ps were observed in the PB of 91% of the patients (40 of 44 cases). No MC B/Ps were found in the PB of 4 patients. MC B/P detection in PB by FCM screening could effectively predict the incidence of EBV+ PTLD with a sensitivity of 90.91% and specificity of 98.40%. The positive predictive value was 85.17% and the negative predictive value was 99.08%. There was no significant correlation between EBV viral copy number and percentage of MC B/P. The median fellow-up time was 6 months (range: 2 days to 21 months) for all patients. The therapeutic response rate was 87.5% (35 of 40 patients) for MC B/P positive EBV+ PTLD patients. In those patients with a therapeutic response, clinical symptoms improved, lymph nodes significantly shrank, EBV viral loads decreased, MC B/Ps decreased or vanished, and CD20+ cell proportion decreased or vanished. Among the 7 patients who had MC B/Ps in PB but were not diagnosed with PTLD , their clinical symptoms recovered after treatment with immunosuppressive therapy. Conclusion By detecting PB MC B/Ps using FCM, we can successfully screen for EBV+ PTLD and monitor patient therapeutic responses in most cases. FCM to detect MC B/Ps in PB is a new, promising method for the diagnosis and monitoring of EBV+ PTLD. Compared to a biopsy, this appears to be a more simple, easier and more applicable tool to diagnose and monitor EBV+ PTLD. Disclosures No relevant conflicts of interest to declare.

Off-the-shelf EBV-specific T-cell Immunotherapy for EBV-associated PTLD.

Off-the-shelf EBV-specific T-cell Immunotherapy for EBV-associated PTLD.

Toxoplasmic Encephalitis Followed by Primary EBV-Associated Post-Transplant Lymphoproliferative Disorder of the Central Nervous System in a Patient Undergoing Allogeneic Hematopoietic Stem Cell Transplant: A Case Report

Toxoplasmic encephalitis (TE) and post-transplant lymphoproliferative disorder of the central nervous system (CNS-PTLD) are major complications after allogeneic hematopoietic stem cell transplant (allo-SCT); both are fatal without timely diagnosis and disease-specific treatment. Differential diagnosis of TE and CNS-PTLD can be challenging because brain biopsy, a gold standard for diagnosis, is sometimes not possible, owing to poor patient condition after allo-SCT. Here, we describe a case of isolated CNS-PTLD arising during the therapeutic course of TE. A 51-year-old man was admitted with mental abnormalities and fever on Day 106 after allo-SCT to treat myelodysplastic syndrome. Magnetic resonance imaging (MRI) revealed multiple nodular and ring-enhanced lesions in the brain, and the result of polymerase chain reaction (PCR) for Toxoplasma gondii in cerebrospinal fluid was positive; therefore, he was diagnosed with TE. Anti-Toxoplasma therapy led to clinical improvement, and the result of subsequent PCR was negative. However, he developed left-sided hemiplegia on Day 306. Head MRI revealed a new lesion and a growing lesion, presenting as ring-enhanced nodules. Brain biopsy was performed, and a pathologic diagnosis of Epstein-Barr virus–associated CNS-PTLD was made. There was no evidence of TE. He was treated successfully by reducing immunosuppressants, followed by rituximab administration and a donor lymphocyte infusion, resulting in complete remission. While T.gondii–specific PCR has great value for diagnosis of TE, CNS-PTLD can be diagnosed only by brain biopsy; hence, brain biopsy may be warranted in cases of suspected PTLD.

Post-transplant Lymphoproliferative Disorder of Naso-orbital Region in Adult Renal Transplant Recipients: A Case Report and Literature Review

Post-transplant lymphoproliferative disorder (PTLD) is an uncommon but fatal complication following both solid organ and hematologic stem cell transplantations. Epstein-Barr virus (EBV) has been considered a main etiologic agent causing PTLD, especially in the first year after transplantation. Extranodal manifestations are frequently found in PTLD; however, naso-orbital involvement in adults is rare. We report a case of EBV-associated PTLD of the naso-orbital region in a 72-year-old patient that occurred 10 years after kidney transplant. Six additional adults with naso-orbital PTLD were identified after completing this literature review, including 2 cases with eyelid swelling, 3 cases with proptosis, and 1 case with facial numbness. The majority of cases occurred after 1 year of transplantation and were associated with EBV. This report emphasizes recognizing PTLD as differential diagnosis in transplant recipients who present with naso-orbital symptoms.

Epstein-Barr Virus-Associated Post-Transplant Lymphoproliferative Disorders after Hematopoietic Stem Cell Transplantation: Pathogenesis, Risk Factors and Clinical Outcomes

Epstein-Barr virus (EBV) is a ubiquitous virus belonging to the human γ-herpes virus subfamily. After primary infection, EBV maintains a life-long latent infection. A major concern is that EBV can cause a diverse range of neoplasms and autoimmune diseases. In addition, patients undergoing hematopoietic stem cell transplantation or solid organ transplantation can experience post-transplant lymphoproliferative disorders (PTLDs) due to dysfunction or suppression of host’s immune system, or uncontrolled proliferation of EBV-infected cells. In recent years, the number of EBV-associated PTLD cases has increased. This review focuses on the current understandings of EBV-associated PTLD pathogenesis, as well as the risk factors and clinical outcomes for patients after allogeneic stem cell transplantation.

Idiopathic pulmonary fibrosis lung transplant recipients are at increased risk for EBV-associated posttransplant lymphoproliferative disorder and worse survival.

Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disorder (EBV-PTLD) is a serious complication in lung transplant recipients (LTRs) associated with significant mortality. We performed a single-center retrospective study to evaluate the risks for PTLD in LTRs over a 7-year period. Of 611 evaluable LTRs, we identified 28 cases of PTLD, with an incidence of 4.6%. Kaplan-Meier analysis showed a decreased freedom from PTLD in idiopathic pulmonary fibrosis (IPF)-LTRs (P<.02). Using a multivariable Cox proportional hazards model, we found IPF (hazard ratio [HR] 3.51, 95% confidence interval [CI] 1.33-8.21, P=.01) and alemtuzumab induction therapy (HR 2.73, 95% CI 1.10-6.74, P=.03) as risk factors for PTLD, compared to EBV mismatch (HR: 34.43, 95% CI 15.57-76.09, P<.0001). Early PTLD (first year) was associated with alemtuzumab use (P=.04), whereas IPF was a predictor for late PTLD (after first year) (P=.002), after controlling for age and sex. Kaplan-Meier analysis revealed a shorter time to death from PTLD in IPF LTRs compared to other patients (P=.04). The use of alemtuzumab in EBV mismatch was found to particularly increase PTLD risk. Together, our findings identify IPF LTRs as a susceptible population for PTLD. Further studies are required to understand the mechanisms driving PTLD in IPF LTRs and develop strategies to mitigate risk.

INCREASED SUSCEPTIBILITY TO HERPESVIRUS COMPLICATIONS IN PULMONARY FIBROSIS LUNG TRANSPLANT RECIPIENTS WITH SHORT TELOMERES

SESSION TITLE: Late Breaking Pulmonary Fibrosis SESSION TYPE: Original Investigations PRESENTED ON: 10/22/2019 08:45 AM - 09:45 AM PURPOSE: Idiopathic Pulmonary Fibrosis (IPF) is the leading indication for lung transplantation in North America, however transplant survival rates in this population lag behind all other end-stage lung diseases. Herpesvirus infectious complications are common causes of morbidity and mortality among lung transplant recipients (LTRs). We recently demonstrated that a high percentage of IPF lung transplant recipients (IPF-LTRs) have short lymphocyte telomere length (short TL) using flow cytometry and fluorescence in situ hybridization. Cytomegalovirus (CMV) infection continues to be one of the most common opportunistic infections in LTRs and is associated with chronic lung allograft dysfunction (CLAD). Epstein Barr virus (EBV)-associated post-transplant lymphoproliferative disorder (PTLD) is a herpesvirus transplant complication that is associated with significant mortality. METHODS: We performed retrospective outcomes analyses combined with genetic analyses in a single institution LTR cohort. RESULTS: We have shown that IPF-LTRs with short TL have increased susceptibility to CMV viremia and other CMV complications post-transplant, compared to age-matched non-IPF-LTRs (P < 0.01). In addition, we find that IPF-LTRs with short TL demonstrate impaired CMV-specific T cell immunity compared to non-IPF-LTRs. We evaluated a cohort of 611 LTRs at our institution from 2010-2016 for EBV-associated post-transplant lymphoproliferative disorder (PTLD) and found 28 cases of PTLD (4.6% incidence). Of these, 12/28 patients (43%) were IPF-LTRs and IPF was a risk factor associated with PTLD (Odds ratio: 2.9; 95% CI: 1.2-6.9; P<0.02). Kaplan Meier analyses demonstrated a significant decreased freedom from EBV-associated PTLD among IPF-LTRs (P<0.02), as well as decreased survival with PTLD in IPF-LTRs with PTLD (P<0.05). In addition, EBV mismatch (donor+/recipient-), a known risk factor for PTLD, carried an increased risk (Odds ratio: 6.9; 95% CI 2.3-20.9; P<0.001), while other factors such as male sex or age (risk factors for IPF) were not associated with increase risk for PTLD. Using both targeted exome sequencing and whole genome sequencing approaches, we found genetic mutations in either telomere or telomere-maintenance genes associated with the short telomere syndrome among both the CMV cohort and IPF-LTRs with EBV-PTLD. CONCLUSIONS: Together, these data highlight a predominance of short TL among current IPF-LTRs, along with increased susceptibility to herpesvirus complications in IPF-LTRs as manifestations of the short telomere syndrome. The identification of IPF-LTRs at increased risk for herpesvirus complications using telomere length and genome sequencing, may allow the development of clinical strategies to mitigate these post-transplant complications. CLINICAL IMPLICATIONS: Short telomeres are common in IPF LTRs. Stratification of risk for CMV and EBV-PTLD can advance strategies to mitigate adverse clinical outcomes. DISCLOSURES: No relevant relationships by Jonathan Alder, source=Web Response No relevant relationships by Stefanie Hannan, source=Web Response No relevant relationships by Carlo Iasella, source=Web Response No relevant relationships by Ritchie Koshy, source=Web Response No relevant relationships by John McDyer, source=Web Response No relevant relationships by Matthew Morrell, source=Web Response No relevant relationships by Seyed Mehdi Nouraie, source=Web Response No relevant relationships by Joseph Pilewski, source=Web Response No relevant relationships by Iulia Popescu, source=Web Response No relevant relationships by Pablo Sanchez, source=Web Response no disclosure on file for Fernanda Silveira; No relevant relationships by Spencer Winters, source=Web Response

Dual blockade of the PI3K/Akt/mTOR pathway inhibits posttransplant Epstein-Barr virus B cell lymphomas and promotes allograft survival.

Posttransplant lymphoproliferative disorder (PTLD) is a serious complication of organ transplantation that often manifests as Epstein-Barr virus (EBV)-associated B cell lymphomas. Current treatments for PTLD have limited efficacy and can be associated with graft rejection or systemic toxicities. The mTOR inhibitor, rapamycin, suppresses tumor growth of EBV+ B cell lymphoma cells in vitro and in vivo; however, the efficacy is limited and clinical benefits of mTOR inhibitors for PTLD are variable. Here, we show constitutive activation of multiple nodes within the PI3K/Akt/mTOR pathway in EBV+ PTLD-derived cell lines. Inhibition of either PI3K or Akt, with specific inhibitors CAL-101 and MK-2206, respectively, diminished growth of EBV+ B cell lines from PTLD patients in a dose-dependent manner. Importantly, rapamycin combined with CAL-101 or MK-2206 had a synergistic effect in suppressing cell growth as determined by IC50 isobolographic analysis and Loewe indices. Moreover, these combinations were significantly more effective than rapamycin alone in inhibiting tumor xenograft growth in NOD-SCID mice. Finally, both CAL-101 and MK-2206 also prolonged survival of heterotopic cardiac allografts in C57BL/6 mice. Thus, combination therapy with rapamycin and a PI3K inhibitor, or an Akt inhibitor, can be an efficacious treatment for EBV-associated PTLD, while simultaneously promoting allograft survival.

NK Cell Recognition of Peptides Encoded by EBV Latent Cycle Proteins

Introduction Epstein–Barr virus (EBV) infects more than 90% of adults worldwide and is associated with several malignancies, including post-transplant lymphoproliferative disorder (PTLD). Although EBV infection is typically asymptomatic in immune-competent individuals, transplant recipients, especially children, are highly susceptible to EBV-associated PTLD due to the immunosuppression treatment required to prevent graft rejection. Innate immune responses, including Natural Killer (NK) cells, are considered vital early in the infection process. Our group has recently demonstrated that a specific NK cell subset can recognize and respond to autologous B cells latently infected with EBV. This NK subset expresses NKG2A/CD94, an inhibitory receptor that recognizes HLA-E. Since EBV-infected cells induced NK cell activation despite the expression of HLA-E, we hypothesize that EBV encoded peptides play a pivotal role in the recognition and response of NKG2A+ NK cells towards latently infected EBV+ cells. Methods and Results Using in silico analysis (NetMHCpan 4.0) a peptide library derived from EBV latent cycle proteins (LMPs and EBNAs) was generated. Initial assessment resulted in a library of 61 peptides which could potentially bind to HLA-E. Then, using target cells, we performed a peptide stabilization assay in vitro to test the ability of individual peptides to be presented by HLA-E. We identified 37 peptides, expressed during the latency III stage of EBV infection that bound and induced HLA-E expression at the surface of the target cells. Functional assays, using CD107a as a readout for NK cell activity, demonstrated HLA-E bound EBV-derived peptides were able to inhibit NK cell activation (15 peptides), or prevent NK cell inhibition via the NKG2A receptor, resulting in NK cell activation (12 peptides). We determined that, in general, peptides encoded by LMPs tended to favor NK cell degranulation (NK cell killing) while peptides encoded by EBNAs were mostly inhibitory. Conclusions Our results demonstrate that EBV latent cycle proteins can encode for peptides that bind to HLA-E which have the ability to promote NK cell degranulation and therefore may be involved in the elimination of EBV latently infected B cells. As NK cells are less susceptible to immunosuppression, understanding NK cell interactions with EBV-infected cells will lead to improvements in therapeutic strategies to control EBV diseases post-transplant. Stanford Transplantation and Tissue engineering center of Excellence (TTE) Fellowship.

Epstein–Barr Virus DNAemia and co-occurrence with cytomegalovirus DNAemia in postrenal transplant recipients from a tertiary care center

Aim: Co-occurrence of Epstein–Barr virus (EBV) with Cytomegalovirus (CMV) is associated with an increased risk of EBV-associated posttransplant lymphoproliferative disorder (PTLD). Quantitation of EBV by real-time polymerase chain reaction (PCR) can aid the clinicians in the initiation of preemptive measures to improve the survival of the graft. Methods: The study was conducted among postrenal transplant recipients (PRTRs) who were attending the nephrology department from 2011 to 2016. Real-time quantitative PCR for EBV was performed in whole blood. PRTRs were classified into asymptomatic with altered renal parameters (Group A) and symptomatic (Group B), which were further subcategorized into Group B1 (fever with anemia, leukopenia, thrombocytopenia, or altered liver enzymes (any two), Group B2 (Group B1 + end-organ disease or only end-organ disease), and Group B3 (graft dysfunction [GDF]). The posttransplant period was also defined. DNA was extracted (Qiagen, Hilden, Germany) from whole blood, and real-time PCR was performed using QuantiTect multiplex PCR kit. Unpaired t-tests and ANOVA were used to analyze the data. Results: A total of 89 PRTRs were enrolled, of which 39.3% (n = 35) had EBV DNAemia, 43.1% during very late, 41.1% in late and 28.6% in immediate post transplant periods. EBV DNAemia ranged from 324 to 32,436 copies/ml. EBV DNAemia was found in 84% (n = 75) of symptomatic (Group B) and 16% (n = 14) of asymptomatic (Group A). Among the PRTRs with GDF (Group B3), 44% (n = 11/25) had EBV DNAemia of 2893.9 ± 1869 copies/ml. EBV DNAemia was considerably higher in PRTRs without GDF (8700.2 ± 9675.6 copies/ml) than PRTRs with GDF and the difference was statistically significant (P = 0.004). EBV DNAemia with CMV DNAemia among PRTRs was found in 21.3% (n = 19). Conclusion: High EBV DNAemia may precede PTLD or GDF; therefore, regular screening of EBV DNAemia is warranted. CMV and EBV DNAemia may also co-exist in PRTRs. As CMV is an immunomodulating virus, it increases the risk of opportunistic infections, especially EBV.

Cytokine Gene Polymorphisms and Epstein-Barr Virus Infection after Allogeneic Hematopoietic Stem Cell Transplantation

Backgroud:Epstein-Barr virus (EBV) infection/reactivation and associated diseases remain common complications in recipients of HSCT, leading to severe end-organ diseases and malignance. Single nucleotide polymorphism (SNP) in cytokine genes is considered to be related with EBV-associated post-transplant lymphoproliferative disorders (PTLD) in solid-organ transplantation recipients. In this study, we analyzed the association between cytokine gene polymorphisms and EBV infection/reactivation or diseases in recipients undergoing allo-HSCT.Methods:A total of 233 patients who received allo-HSCT between March 2012 to December 2014 were enrolled in this study. Ten SNPs, including IL-1β -511 rs16944, IL-1RN +11100 rs315952, IL-2 -330 rs2069762, IL-4 -590 rs2243250, IL-10 -592 rs1800872, IL-12 +1188 rs3212227, TNF-α -308 rs1800629, TGF-β1-509 rs1800469, TGF-β1 +869 rs1800470, IFN-γ +874 rs2430561, were tested. The SNPs genotypes in patients with or without EBV infection/reactivation and associated diseases were compared. Besides, the risk factors for EBV infection/reactivation were studied.Results:Seventy-four patients developed EBV infection/reactivation. The patients with EBV infection/reactivation had higher frequencies of donor IL-1β -511 TT genotype, donor IL-4 -590 TT genotype and recipient TNF-α -308 GG genotype than those without (p=0.021, p=0.004, p=0.020, respectively) while the frequencies of donor IL-1β -511 CC genotype, donor IL-1RN +11100 TT genotype, donor IL-2 -330 TT genotype, donor IL-4 -590 CC genotype and recipient TNF-α-308 GA genotype in patients with EBV infection/reactivation were lower than those without (p=0.041, p=0.029, p=0.005, p=0.011, p=0.042, respectively). Multivariate analysis showed donor IL-4 -590TT genotype (p=0.016, HR=1.907, 95% CI =1.130-3.218) and recipient TNF-α -308GG genotype (p=0.002, HR=3.550, 95% CI=1.613-7.812) were risk factors for post-transplant EBV infection/reactivation while donor IL-1RN +11100TT genotype (p=0.001, HR=0.382, 95% CI=0.218-0.670) was protective factors for post-transplant EBV infection/reactivation. Twenty-one patients developed EBV-associated diseases. The patients who developed EBV-associated diseases had higher frequency of donor IFN-γ +874 AT genotype than those did not (p=0.027). On the contrary, the frequencies of donor IL-1β-511 CC genotype, donor IL-10 -592 AA genotype, donor IL-12 +1188 AA genotype and donor IFN-γ +874 AA genotype in patients with EBV-associated diseases were lower than those without (p=0.019, p=0.018, p=0.018, p=0.010, respectively).Conclusion:Several SNPs in cytokine genes might be associated with EBV infection/reactivation and the development of EBV-associated diseases in recipients of allo-HSCT. However, these association should be studied further. DisclosuresNo relevant conflicts of interest to declare.

Intrathecal Rituximab for EBV-Associated Post-Transplant Lymphoproliferative Disorder with Central Nervous System Involvement Unresponsive to Intravenous Rituximab-Based Treatments: A Prospective Study

▪Backgroud:Although the introduction of rituximab as a first-line treatment has improved outcome of post-transplant lymphoproliferative disorder (PTLD), PTLD with central nervous system involvement (CNS-PTLD) still has a dismal prognosis because of low penetrance across the blood-brain barrier. In this prospective study, we reported intrathecal rituximab was efficacy and safety in the patients with CNS-PTLD who had failed to respond to the intravenous rituximab-based treatments.Methods:From June 2009 to November 2013, 32 cases of EBV-associated PTLD were recorded in the Southern Medical University Institute of Hematology. Fourteen patients diagnosed with CNS-PTLD were enrolled in this prospective study. For the patients who failed to response to the initial intravenous rituximab-based treatments, sequential dose-escalation schedule of intrathecal rituximab (initial dose of 20mg, increased by 10mg each week and maximum dose of 50 mg) was administrated weekly.Results:Three patients were responsive and 11 were unresponsive to the initial treatments within one week after the treatments. For the 11 patients who failed to respond to the initial treatments, 9 patients received intrathecal rituximab within 7-11 days and 2 patients refused the treatment. After two cycles of rituximab-based treatments, 10 patients achieved complete response (CR), 2 patients were partial response and 2 patients were non-response. With a median follow up of 664 (range 18 to 1545) days after the diagnosis of CNS-PTLD, 7 patients survived and 7 died. The causes of death included PTLD progressing (n=3), PTLD relapse (n=1), GVHD (n=1), CMV pneumonia (n=1) and pseudomonas aeruginosa sepsis (n=1). The 3-year probability of OS was 45.7% ±14.7% in CNS-PTLD, which was no significant difference as compared to PTLD without CNS involvement(55.6% ±11.7%, P=0.706).Conclusion:Intrathecal rituximab might be an effective and safe method for CNS-PTLD in the allo-HSCT recipients who were unresponsive to the intravenous rituximab-based treatments. DisclosuresNo relevant conflicts of interest to declare.

A Comprehensive Analysis of the Cellular and EBV-Specific MicroRNAome in Primary CNS PTLD Identifies Different Patterns Among EBV-Associated Tumors

Primary central nervous system (pCNS) posttransplant lymphoproliferative disorder (PTLD) is a complication of solid organ transplantation characterized by poor outcome. In contrast to systemic PTLD, Epstein-Barr virus (EBV)-association of pCNS PTLD is almost universal, yet viral and cellular data are limited. To identify differences in the pattern of EBV-association of pCNS and systemic PTLD, we analyzed the expression of latent and lytic EBV transcripts and the viral and cellular microRNAome in nine pCNS (eight EBV-associated) and in 16 systemic PTLD samples (eight EBV-associated). Notably although 15/16 EBV-associated samples exhibited a viral type III latency pattern, lytic transcripts were also strongly expressed. Members of the ebv-miR-BHRF1 and ebv-miR-BART clusters were expressed in virtually all EBV-associated PTLD samples. There were 28 cellular microRNAs differentially expressed between systemic and pCNS PTLD. pCNS PTLD expressed lower hsa-miR-199a-5p/3p and hsa-miR-143/145 (implicated in nuclear factor kappa beta and c-myc signaling) as compared to systemic PTLD. Unsupervised nonhierarchical clustering of the viral and cellular microRNAome distinguished non-EBV-associated from EBV-associated samples and identified a separate group of EBV-associated pCNS PTLD that displayed reduced levels of B cell lymphoma associated oncomiRs such as hsa-miR-155, -21, -221 and the hsa-miR-17-92 cluster. EBV has a major impact on viral and cellular microRNA expression in EBV-associated pCNS PTLD.