Project description:Epstein-Barr virus (EBV) establishes a lifelong latent infection in healthy humans, kept under immune control by cytotoxic T cells (CTLs). Following paediatric haematopoetic stem cell transplantation (HSCT), a loss of immune surveillance leads to opportunistic outgrowth of EBV-infected cells, resulting in EBV reactivation, which can ultimately progress to post-transplant lymphoproliferative disorder (PTLD). The aims of this study were to identify risk factors for EBV reactivation in children in the first 100 days post-HSCT and to assess the suitability of a previously reported mathematical model to mechanistically model EBV reactivation kinetics in this cohort. Retrospective electronic data were collected from 56 children who underwent HSCT at Great Ormond Street Hospital (GOSH) between 2005 and 2016. Using EBV viral load (VL) measurements from weekly quantitative PCR (qPCR) monitoring post-HSCT, a multivariable Cox proportional hazards (Cox-PH) model was developed to assess time to first EBV reactivation event in the first 100 days post-HSCT. Sensitivity analysis of a previously reported mathematical model was performed to identify key parameters affecting EBV VL. Cox-PH modelling revealed EBV seropositivity of the HSCT recipient and administration of anti-thymocyte globulin (ATG) pre-HSCT to be significantly associated with an increased risk of EBV reactivation in the first 100 days post-HSCT (adjusted hazard ratio (AHR) = 2.32, P = 0.02; AHR = 2.55, P = 0.04). Five parameters were found to affect EBV VL in sensitivity analysis of the previously reported mathematical model. In conclusion, we have assessed the effect of multiple covariates on EBV reactivation in the first 100 days post-HSCT in children and have identified key parameters in a previously reported mechanistic mathematical model that affect EBV VL. Future work will aim to fit this model to patient EBV VLs, develop the model to account for interindividual variability and model the effect of clinically relevant covariates such as rituximab therapy and ATG on EBV VL.

Project description:ABSTRACT Importance Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is considered the only effective treatment for chronic active Epstein–Barr virus infection (CAEBV). The clinical efficacy and safety of allo‐HSCT with different conditioning regimens in children with CAEBV remain unclear. Objective To evaluate the effectiveness and safety of allo‐HSCT with the modified myeloablative conditioning (MAC) regimen for children with CAEBV and also the factors affecting the outcomes. Methods We retrospectively analyzed children with CAEBV who underwent allo‐HSCT with the modified MAC regimen at Beijing Children's Hospital, Capital Medical University from October 2016 to June 2021. Data related to the clinical manifestations, engraftment, and outcome were extracted from the medical records. Results The cohort comprised 41 patients (24 males, 17 females) with a median transplantation age of 92.6 (60.4, 120.7) months and a median follow‐up time of 28.2 (15.3, 40.2) months. Four patients (9.8%) died, among which three died from primary disease relapse, and one died from grade IV acute graft‐versus‐host diseases (aGVHD) after stopping treatment. The 3‐year overall survival (OS) and 3‐year event‐free survival (EFS) rates were 88.8% ± 5.4% and 85.0% ± 5.7%, respectively. The 3‐year OS and EFS did not significantly differ between the patients with hemophagocytic lymphohistiocytosis (HLH) and the patient without HLH (87.7% ± 6.8% vs. 91.7% ± 8.0%, P = 0.790; 85.0% ± 6.9% vs. 84.6% ± 10.0%, P = 0.921), or among the patients with complete remission, partial remission, and activity disease before HSCT (all P > 0.05). Multivariate analysis showed that grade III–IV aGVHD was a risk factor for mortality (Hazards ratio: 11.65, 95% confidence interval: 1.00, 136.06; P = 0.050). Interpretation Allo‐HSCT with the modified MAC regimen is safe and effective for pediatric CAEBV. This treatment benefits patients with HLH or active disease. Patients with Grade III–IV aGVHD may be associated with worse outcomes. Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) with the modified myeloablative conditioning (MAC) regimen is safe and effective for pediatric chronic active Epstein–Barr virus. The 3‐year overall survival (OS) and 3‐year event‐free survival (EFS) rates were 88.8% ± 5.4% and 85.0% ± 5.7%, respectively. The 3‐year OS and EFS did not significantly differ between the hemophagocytic lymphohistiocytosis (HLH) and non‐HLH groups, or among the complete remission, partial remission, and activity disease groups. Patients with concomitant HLH and patients with the active disease before allo‐HSCT also benefit from modified MAC‐HSCT. Patients with grade III–IV acute graft‐versus‐host diseases (aGVHD) had lower 3‐year OS and EFS rates than those without aGVHD or with grade I–II aGVHD.

Project description:Epstein-Barr virus (EBV) reactivation involves the ordered induction of approximately 90 viral genes that participate in the generation of infectious virions. Using strand-specific RNA-seq to assess the EBV transcriptome during reactivation, we found extensive bidirectional transcription extending across nearly the entire genome. In contrast, only 4% of the EBV genome is currently bidirectionally annotated. Most of the newly identified transcribed regions show little evidence of coding potential, supporting noncoding roles for most of these RNAs. Based on previous cellular long noncoding RNA size calculations, we estimate that there are likely hundreds more EBV genes expressed during reactivation than was previously known. Limited 5' and 3' rapid amplification of cDNA ends (RACE) experiments and findings of novel splicing events by RNA-seq suggest that the complexity of the viral genome during reactivation may be even greater. Further analysis of antisense transcripts at some of the EBV latency gene loci showed that they are "late" genes, they are nuclear, and they tend to localize in areas of the nucleus where others find newly synthesized viral genomes. This raises the possibility that these transcripts perform functions such as new genome processing, stabilization, organization, etc. The finding of a significantly more complex EBV transcriptome during reactivation changes our view of the viral production process from one that is facilitated and regulated almost entirely by previously identified viral proteins to a process that also involves the contribution of a wide array of virus encoded noncoding RNAs. Epstein-Barr virus (EBV) is a herpesvirus that infects the majority of the world's population, in rare cases causing serious disease such as lymphoma and gastric carcinoma. Using strand-specific RNA-seq, we have studied viral gene expression during EBV reactivation and have discovered hundreds more viral transcripts than were previously known. The finding of alternative splicing and the prevalence of overlapping transcripts indicate additional complexity. Most newly identified transcribed regions do not encode proteins but instead likely function as noncoding RNA molecules which could participate in regulating gene expression, gene splicing or even activities such as viral genome processing. These findings broaden the scope of what we need to consider to understand the viral manufacturing process. As more detailed studies are undertaken they will likely change the way we view this process as a whole.

Dataset Information

Characteristics of Epstein-Barr virus reactivation after allogeneic haematopoietic stem cell transplantation in patients with chronic active Epstein-Barr virus disease: favorable responses to rituximab.

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