Norovirus (NoV) genogroups I and II (GI and GII) are now recognized as the predominant worldwide cause of outbreaks of acute gastroenteritis in humans. Three recombinant NoV GII isolates were identified and characterized, 2 of which are unrelated to any previously published recombinant NoV. Using data from the current study, published sequences, database searches, and molecular techniques, we identified 23 recombinant NoV GII and 1 recombinant NoV GI isolates. Analysis of the genetic relationships among the recombinant NoV GII isolates identified 9 independent recombinant sequences; the other 14 strains were close relatives. Two of the 9 independent recombinant NoV were closely related to other recombinants only in the polymerase region, and in a similar fashion 1 recombinant NoV was closely related to another only in the capsid region. Breakpoint analysis of recombinant NoV showed that recombination occurred in the open reading frame (ORF)1/ORF2 overlap. We provide evidence to support the theory of the role of subgenomic RNA promoters as recombination hotspots and describe a simple mechanism of how recombination might occur in NoV.

Key Points• Infusion of CMV-specific T cells early posttransplant does not increase acute or chronic graft-versus-host disease.• CMV-specific T cells early posttransplant reduce the need for pharmacotherapy without increased rates of CMV-related organ damage.We investigated the use of adoptively transferred donor-derived cytomegalovirus (CMV) specific cytotoxic T lymphocytes (CTL) as immune reconstitution postallogeneic transplant in a phase 2 study. Fifty patients were infused with a single dose of 2 3 10 7 cells/m 2 after day 28 post-transplant. Twenty-six patients reactivated CMV posttransplant (only 5 post-CTL infusion) and 9 required therapy with ganciclovir or foscarnet (only 1 post-CTL infusion).There was 1 case of fatal CMV disease, attributable to high levels of antithymocyte globulin at the time of T cell infusion. We compared the patients in the phase 2 study with a group of contemporaneous controls also treated at the trial centers. There was no increase in acute or chronic graft-versus-host disease attributable to CTL infusion; overall and progressionfree survival were similar in both groups. There was a reduction in the percentage of patients who required CMV directed antiviral therapy (17% vs 36%, P 5 .01) and in the total number of treatment days in the cohort receiving CTL (3.4 days vs 8.9 days, P 5 .03) without a reduction in CMV reactivation rates. We postulate that adoptively transferred cells are able to expand in response to viral antigen, limit viral replication, and prevent progression to tissue infection. This study was registered on the Australian Clinical

Key Points Partially HLA-matched third-party CMV-specific T cells provide long-term viral control in HSCT patients with resistant CMV infection. Viral control occurs in the setting of recovery of CD8+ terminally differentiated effector T cells.

We performed a Phase I clinical trial of donor derived CD19-specific chimeric antigen receptor T-cells (CAR T-cells) for B-cell malignancy that relapsed or persisted after matched related allogeneic hemopoietic stem cell transplant. To overcome the cost and transgene capacity limitations of traditional viral vectors, CAR T-cells were produced using the piggyBac transposon system of genetic modification. Following CAR T-cell infusion, one patient developed a gradually enlarging retroperitoneal tumor due to a CAR expressing CD4+ T-cell lymphoma. Screening of other patients led to the detection of a second CAR T-cell tumor in thoracic para-aortic lymph nodes in an asymptomatic patient. Analysis of the first lymphoma showed a high transgene copy number, but no insertion into typical oncogenes. There were also structural changes such as altered genomic copy number and point mutations unrelated to the insertion sites. Transcriptome analysis showed transgene promoter driven upregulation of transcription of surrounding regions despite insulator sequences surrounding the transgene. However, marked global changes in transcription predominantly correlated with gene copy number rather than insertion sites. In both patients, the CAR T-cell derived lymphoma progressed and one patient died. We describe the first two cases of malignant lymphoma derived from CAR gene modified T-cells. Although CAR T-cells have an enviable record of safety to date, our results emphasize the need for caution and regular follow up of CAR T recipients, especially when novel methods of gene transfer are used to create genetically modified immune therapies. The trial was registered at www.anzctr.org.au as ACTRN12617001579381.

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CD19-specific chimeric antigen receptor (CAR19) T-cells effectively induce remission of B-cell malignancy, but the cost and complexity of production using viral vectors is a factor limiting widespread application. Furthermore, the small cargo capacity of viral vectors may hamper future development of more heavily engineered CAR T-cells. We demonstrated the feasibility of generating CAR19 T-cells from HLA-matched donors of sibling allogeneic hematopoietic stem cell transplant (HSCT) patients via a simple and inexpensive method using the high-capacity piggyBac transposon. A cohort of 10 patients with relapsed or refractory B-cell acute lymphoblastic leukemia or aggressive lymphoma following HSCT were the first human subjects to receive piggyBac-generated CAR19 T-cells. Treatment with intra-patient escalating doses of CAR19 T-cells was effective, with all 9 evaluable patients achieving complete remission. At a median follow-up of 18.0 months, 5 patients remained in complete remission of B-cell malignancy. One patient died of viral sepsis. Four patients developed cytokine release syndrome of maximum grade 2, and no neurotoxicity or new graft-versus-host disease occurred. However, two patients developed malignant CAR19 T-cell tumors, one of whom was successfully treated; one patient died of the secondary tumor. The piggyBac system represents a feasible alternative to viral vectors for the generation of effective CAR19 T-cells, but its oncogenic potential in the context of the described production process will need to be addressed before any further clinical use is possible. This trial was registered at www.anzctr.org.au as ACTRN12617001579381.

Primary central nervous system lymphoma (PCNSL) is confined to the brain, eyes, and cerebrospinal fluid without evidence of systemic spread. Rarely, PCNSL occurs in the context of immunosuppression, e.g. post-transplant lymphoproliferative disorders (PTLD) or HIV (AIDS-related PCNSL). These cases are poorly characterized, have dismal outcome and are typically Epstein-Barr virus (EBV)-tissue positive. We used targeted sequencing and digital multiplex gene expression to compare the genetic landscape and tumor microenvironment (TME) of 91 PCNSL tissues all with diffuse large B-cell lymphoma histology. 47 were EBV-tissue negative: 45 EBV(-) HIV(-) PCNSL, 2 EBV(-) HIV(+) PCNSL; and 44 were EBV-tissue positive: 23 EBV(+) HIV(+) PCNSL, 21 EBV(+) HIV(-) PCNSL. As with prior studies, EBV(-) HIV(-) PCNSL had frequent MYD88, CD79B and PIM1 mutations, and enrichment for the activated B-cell (ABC) cell-of-origin (COO) sub-type. In contrast, these mutations were absent in all EBV-tissue positive cases and ABC frequency was low. Furthermore, copy number loss in HLA-class I/II and antigen presenting/processing genes were rarely observed, indicating retained antigen presentation. To counter this, EBV(+) HIV(-) PCNSL had a tolerogenic TME with elevated macrophage and immune-checkpoint gene expression, whereas AIDS-related PCNSL had low CD4 gene counts. EBV-tissue positive PCNSL in the immunosuppressed is immunobiologically distinct from EBV(-) HIV(-) PCNSL, and despite expressing an immunogenic virus retains the ability to present EBV-antigens. Results provide a framework for targeted treatment.