Evolution of the clinical-stage hyperactive TcBuster transposase as a platform for robust non-viral production of adoptive cellular therapies.

Cellular therapies for the treatment of human diseases, such as chimeric antigen receptor (CAR) T and natural killer (NK) cells have shown remarkable clinical efficacy in treating hematological malignancies; however, current methods mainly utilize viral vectors that are limited by their cargo size capacities, high cost, and long timelines for production of clinical reagent. Delivery of genetic cargo via DNA transposon engineering is a more timely and cost-effective approach, yet has been held back by less efficient integration rates. Here, we report the development of a novel hyperactive TcBuster (TcB-M) transposase engineered through structure-guided and in vitro evolution approaches that achieves high-efficiency integration of large, multicistronic CAR-expression cassettes in primary human cells. Our proof-of-principle TcB-M engineering of CAR-NK and CAR-T cells shows low integrated vector copy number, a safe insertion site profile, robust in vitro function, and improves survival in a Burkitt lymphoma xenograft model in vivo. Overall, TcB-M is a versatile, safe, efficient and open-source option for the rapid manufacture and preclinical testing of primary human immune cell therapies through delivery of multicistronic large cargo via transposition.

The Treatment of Burkitt Lymphoma With the Berlin-Frankfurt-Münster Protocol With Rituximab and Consolidative Autologous Transplantation.

INTRODUCTION: Intensive treatment approaches are required for adult patients with Burkitt lymphoma (BL), although an univocal standard of care still does not exist. The use of frontline autologous stem cells transplantation (ASCT) is debated. PATIENTS AND METHODS: Between 2004 and 2020, 50 patients with BL were treated with the Berlin-Frankfurt-Münster (BFM). Treatment plan consisted of 3 blocks, A (ifosfamide, vincristine, methotrexate, etoposide, and cytarabine), B (vincristine, cyclophosphamide, methotrexate, and doxorubicin), and C (vindesine, methotrexate, etoposide, and cytarabine), each repeated twice, every 28 days. Rituximab was given at day 1 each block. Intrathecal prophylaxis was given once per each block. ASCT was scheduled at the end of the 6 blocks after conditioning. RESULTS: Median age at onset was 38 years (range 16-72); stages III-IV disease was observed in 82% of cases; bulky disease occurred in 44% of the patients, with B-symptoms in 38%. Stem cell harvest was performed in 72% of patients, who all received a subsequent ASCT. The full 6 blocks treatment was completed in 70% of the patients. The overall response rate was 74%, with a complete response rate of 60%. Ten-year overall survival and progression-free survival were 83.7% and 76.0%, respectively, without reaching the median. Ten-year disease-free survival was 80.3%. Grades 3-4 neutropenia, thrombocytopenia, anemia, and mucositis were seen in 96%, 60%, 32%, and 24% of patients. Infections occurred in 60% of patients. CONCLUSION: Intensive treatment according to BFM protocol, with rituximab and ASCT, appears feasible, safe, and highly effective in adult patients with BL, as confirmed by long-term survival rates reflecting response maintenance.

Defining and treating high-grade B-cell lymphoma, NOS.

High-grade B-cell lymphoma (HGBL), not otherwise specified (NOS), is a recently introduced diagnostic category for aggressive B-cell lymphomas. It includes tumors with Burkitt-like or blastoid morphology that do not have double-hit cytogenetics and that cannot be classified as other well-defined lymphoma subtypes. HBCLs, NOS, are rare and heterogeneous; most have germinal center B-cell phenotype, and up to 45% carry a single-hit MYC rearrangement, but otherwise, they have no unifying immunophenotypic or cytogenetic characteristics. Recent analyses using gene expression profiling (GEP) revealed that up to 15% of tumors currently classified as diffuse large B-cell lymphoma display an HGBL-like GEP signature, indicating a potential to significantly expand the HGBL category using more objective molecular criteria. Optimal treatment of HGBL, NOS, is poorly defined because of its rarity and inconsistent diagnostic patterns. A minority of patients have early-stage disease, which can be managed with standard R-CHOP-based approaches with or without radiation therapy. For advanced-stage HGBL, NOS, which often presents with aggressive disseminated disease, high lactate dehydrogenase, and involvement of extranodal organs (including the central nervous system [CNS]), intensified Burkitt lymphoma-like regimens with CNS prophylaxis may be appropriate. However, many patients diagnosed at age >60 years are not eligible for intensive immunochemotherapy. An improved GEP- and/or genomic-based pathologic classification that could facilitate HGBL-specific trials is needed to improve outcomes for all patients. In this review, we discuss the current clinicopathologic concept of HGBL, NOS, and existing data on its prognosis and treatment and delineate potential future taxonomy enrichments based on emerging molecular diagnostics.

Spontaneous tumor lysis syndrome (STLS) during biopsy for burkitt lymphoma: a case report.

BACKGROUND: Tumor lysis syndrome (TLS) is a hematologic oncological emergency characterized by metabolic and electrolyte imbalances. On breakdown of tumor cells, enormous amounts of potassium, phosphate, and nucleic acids are released into systemic circulation. TLS mainly occurs during chemotherapy. However, there are rare incidences of spontaneous tumor lysis syndrome (STLS) prior to commencement of therapy. CASE PRESENTATION: In the case being reported, the child had just undergone a biopsy. As the incision was being closed, there was a sudden onset of high fever, arrhythmia, severe hyperkalemia, hypocalcemia, and acidosis. Following timely symptomatic treatment and continuous renal replacement therapy(CRRT), the child's laboratory results improved, and organ function was restored to normal. The final pathological diagnosis confirmed Burkitt lymphoma. The boy is currently on maintenance chemotherapy. CONCLUSIONS: TLS is a potentially life-threatening complication in hematologic oncology. Several important conclusions can be drawn from this case, reminding clinicians to: (1) be fully aware of the risk factors of TLS and evaluate the level of risk; (2) pay attention to the possibility of STLS during operation, if surgical procedures are necessary and operate with minimal trauma and in the shortest time possibly; (3) take preoperative prophylaxis actively for high-risk TLS patients, including aggressive fluid management and rational use of diuretics and uric-acid-lowering drugs. In addition, this case confirms the effectiveness of CRRT for severe STLS.

Burkitt lymphoma after solid-organ transplant: Treatment and outcomes in the paediatric PTLD collaborative.

Burkitt lymphoma arising in paediatric post-solid-organ transplantation-Burkitt lymphoma (PSOT-BL) is a clinically aggressive malignancy and a rare form of post-transplant lymphoproliferative disorder (PTLD). We evaluated 35 patients diagnosed with PSOT-BL at 14 paediatric medical centres in the United States. Median age at organ transplantation was 2.0 years (range: 0.1-14) and age at PSOT-BL diagnosis was 8.0 years (range: 1-17). All but one patient had late onset of PSOT-BL (≥2 years post-transplant), with a median interval from transplant to PSOT-BL diagnosis of 4.0 years (range: 0.4-12). Heart (n = 18 [51.4%]) and liver (n = 13 [37.1%]) were the most frequently transplanted organs. No patients had loss of graft or treatment-related mortality. A variety of treatment regimens were used, led by intensive Burkitt lymphoma-specific French-American-British/Lymphomes Malins B (FAB/LMB), n = 13 (37.1%), and a low-intensity regimen consisting of cyclophosphamide, prednisone and rituximab (CPR) n = 12 (34.3%). Median follow-up was 6.7 years (range: 0.5-17). Three-year event-free and overall survival were 66.2% and 88.0%, respectively. Outcomes of PSOT-BL patients receiving BL-specific intensive regimens are comparable to reported BL outcomes in immunocompetent children. Multi-institutional collaboration is feasible and provides the basis of prospective data collection to determine the optimal treatment regimen for PSOT-BL.

Targeting a cytokine checkpoint enhances the fitness of armored cord blood CAR-NK cells.

Immune checkpoint therapy has resulted in remarkable improvements in the outcome for certain cancers. To broaden the clinical impact of checkpoint targeting, we devised a strategy that couples targeting of the cytokine-inducible Src homology 2-containing (CIS) protein, a key negative regulator of interleukin 15 (IL-15) signaling, with fourth-generation "armored" chimeric antigen receptor (CAR) engineering of cord blood-derived natural killer (NK) cells. This combined strategy boosted NK cell effector function through enhancing the Akt/mTORC1 axis and c-MYC signaling, resulting in increased aerobic glycolysis. When tested in a lymphoma mouse model, this combined approach improved NK cell antitumor activity more than either alteration alone, eradicating lymphoma xenografts without signs of any measurable toxicity. We conclude that targeting a cytokine checkpoint further enhances the antitumor activity of IL-15-secreting armored CAR-NK cells by promoting their metabolic fitness and antitumor activity. This combined approach represents a promising milestone in the development of the next generation of NK cells for cancer immunotherapy.

Molecular characterization and clinical outcome of B-cell precursor acute lymphoblastic leukemia with IG-MYC rearrangement.

Rarely, immunophenotypically immature B-cell precursor acute lymphoblastic leukemia (BCP-ALL) carries an immunoglobulin- MYC rearrangement (IG-MYC-r). This can result in diagnostic confusion with Burkitt lymphoma/leukemia and use of individualized treatment schedules of unproven efficacy. Here we compare the molecular characteristics of these conditions and investigate historic clinical outcome data. We identified 90 cases registered in a national BCP-ALL clinical trial/registry. When present, diagnostic material underwent cytogenetic, exome, methylome and transcriptome analyses. The outcomes analyzed were 3-year event-free survival and overall survival. IG-MYC-r was identified in diverse cytogenetic backgrounds, co-existing with either established BCP-ALL-specific abnormalities (high hyperdiploidy, n=3; KMT2A-rearrangement, n=6; iAMP21, n=1; BCR-ABL1, n=1); BCL2/BCL6-rearrangements (n=15); or, most commonly, as the only defining feature (n=64). Within this final group, precursor-like V(D)J breakpoints predominated (8/9) and KRAS mutations were common (5/11). DNA methylation identified a cluster of V(D)J-rearranged cases, clearly distinct from Burkitt leukemia/lymphoma. Children with IG-MYC-r within that subgroup had a 3-year event-free survival of 47% and overall survival of 60%, representing a high-risk BCP-ALL. To develop effective management strategies this group of patients must be allowed access to contemporary, minimal residual disease-adapted, prospective clinical trial protocols.

Epstein‒Barr virus-associated cellular immunotherapy.

Epstein‒Barr virus (EBV) is a human herpes virus that is saliva-transmissible and universally asymptomatic. It has been confirmed that more than 90% of the population is latently infected with EBV for life. EBV can cause a variety of related cancers, such as nasopharyngeal carcinoma, diffuse large B-cell lymphoma, and Burkitt lymphoma. Currently, many clinical studies have demonstrated that EBV-specific cytotoxic T lymphocytes and other cell therapies can be safely and effectively transfused to prevent and treat some diseases caused by EBV. This review will mainly focus on discussing EBV-specific cytotoxic T lymphocytes and will touch on therapeutic EBV vaccines and chimeric antigen receptor T-cell therapy briefly.

Novel lectin-based chimeric antigen receptors target Gb3-positive tumour cells.

The link between cancer and aberrant glycosylation has recently become evident. Glycans and their altered forms, known as tumour-associated carbohydrate antigens (TACAs), are diverse, complex and difficult to target therapeutically. Lectins are naturally occurring glycan-binding proteins  that offer a unique opportunity to recognise TACAs. T cells expressing chimeric antigen receptors (CARs) have proven to be a successful immunotherapy against leukaemias, but so far have shown limited success in solid tumours. We developed a panel of lectin-CARs that recognise the glycosphingolipid globotriaosylceramide (Gb3), which is overexpressed in various cancers, such as Burkitt's lymphoma, colorectal, breast and pancreatic. We have selected the following lectins: Shiga toxin's B-subunit from Shigella dysenteriae, LecA from Pseudomonas aeruginosa, and the engineered lectin Mitsuba from Mytilus galloprovincialis as antigen-binding domains and fused them to a well-known second-generation CAR. The Gb3-binding lectin-CARs have demonstrated target-specific cytotoxicity against Burkitt's lymphoma-derived cell lines as well as solid tumour cells from colorectal and triple-negative breast cancer. Our findings reveal the big potential of lectin-based CARs as therapeutical applications to target Gb3 and other TACAs expressed in haematological malignancies and solid tumours.

Superior outcomes with paediatric protocols in adolescents and young adults with aggressive B-cell non-Hodgkin lymphoma.

Survival disparities by locus of care (LOC; paediatric versus adult) among adolescents and young adults (AYA) with acute lymphoblastic leukaemia (ALL) are well documented. Whether similar disparities exist among AYA with aggressive mature B-cell non-Hodgkin lymphoma (B-NHL) is unknown. We identified all Ontario, Canada AYA aged 15-21 years at diagnosis of B-NHL between 1992 and 2012. Demographic, disease, treatment and outcome data were chart abstracted. The impact of LOC on event-free (EFS) and overall survival (OS) were determined, adjusted for patient and disease covariates. Among 176 AYA with B-NHL, 62 (35·2%) received therapy at paediatric centres. The 5-year EFS and OS [± standard error (SE)] for the overall cohort were 72·2 [3·4]% and 76·1 [3·2]% respectively. Both EFS and OS were superior among paediatric centre AYA [EFS (± SE) 82·2 (4·9)% vs. 66·7 (4·4)%, P = 0·02; OS 85·5 (4·5)% vs. 71·1 (4·3)%, P = 0·03]. Adjusted for histology, stage and time period, adult centre AYA had inferior EFS [hazard ratio (HR) 2·4, 95% confidence interval (CI) 1·1-4·9, P = 0·02] and OS (HR 2·5, 95% CI 1·1-5·7, P = 0·03). Sensitivity analyses restricted to the latest time period, when most adult centre AYA received rituximab, demonstrated similar disparities. Similar to AYA with ALL, AYA with B-NHL may benefit from being treated with paediatric protocols. Studies prospectively validating these results are warranted.

Ruxolitinib reduces severe CRS response by suspending CAR-T cell function instead of damaging CAR-T cells.

The therapeutic effect of CAR-T is often accompanied by sCRS, which is the main obstacle to the promotion of CAR-T therapy. The JAK1/2 inhibitor ruxolitinib has recently been confirmed as clinically effective in maintaining control over sCRS, however, its mechanism remains unclear. In this study, we firstly revealed that ruxolitinib significantly inhibited the proliferation of CAR-T cells without damaging viability, and induced an efficacy-favored differentiation phenotype. Second, ruxolitinib reduced the level of cytokine release not only from CAR-T cells, but also from other cells in the immune system. Third, the cytolytic activity of CAR-T cells was restored once the ruxolitinib was removed; however, the cytokines released from the CAR-T cells maintained an inhibited state to some degree. Finally, ruxolitinib significantly reduced the proliferation rate of CAR-T cells in vivo without affecting the therapeutic efficacy after withdrawal at the appropriate dose. We demonstrated pre-clinically that ruxolitinib interferes with both CAR-T cells and the other immune cells that play an important role in triggering sCRS reactions. This work provides useful and important scientific data for clinicians on the question of whether ruxolitinib has an effect on CAR-T cell function loss causing CAR-T treatment failure when applied in the treatment of sCRS, the answer to which is of great clinical significance.

Progressive or relapsed Burkitt lymphoma or leukemia in children and adolescents after BFM-type first-line therapy.

Children with refractory or relapsed Burkitt lymphoma (BL) or Burkitt leukemia (B-AL) have a poor chance to survive. We describe characteristics, outcome, reinduction, and transplantation approaches and evaluate risk factors among children with progression of a BL/B-AL included in Non-Hodgkin's Lymphoma-Berlin-Frankfurt-Münster studies between 1986 and 2016. Treatment recommendation was reinduction including rituximab from the early 2000s followed by blood stem cell transplantation. The 3-year survival of the 157 children was 18.5 ± 3%. Survival significantly improved from 11 ± 3% before to 27 ± 5% after 2000 (P < .001), allowing for risk factor analyses among the latter 75 patients. Survival of 14 patients with relapse after initial therapy for low-risk disease (R1/R2) was 50 ± 13% compared with 21 ± 5% for 61 patients progressing after R3/R4 therapy (P < .02). A total of 25 of 28 patients with progression during first-line therapy, 31 of 32 with progression during reinduction, 15 of 16 not reaching a complete remission (CR) before transplantation, 9 of 10 treated with rituximab front-line, and all 13 patients not receiving rituximab during reinduction died. Forty-six patients received stem cell transplantation (20 autologous, 26 allogeneic). Survival after a regimen combining rituximab with continuous-infusion chemotherapy followed by allogeneic transplantation was 67 ± 12% compared with 18 ± 5% for all other regimen and transplantations (P = .003). Patients with relapsed BL/B-AL have a poor chance to survive after current effective front-line therapies. Progression during initial or reinduction chemotherapy and initial high-risk disease are risk factors in relapse. Time-condensed continuous-infusion reinduction followed by stem cell transplantation forms the basis for testing new drugs.

Epigenetic reprogramming sensitizes immunologically silent EBV+ lymphomas to virus-directed immunotherapy.

Despite advances in T-cell immunotherapy against Epstein-Barr virus (EBV)-infected lymphomas that express the full EBV latency III program, a critical barrier has been that most EBV+ lymphomas express the latency I program, in which the single Epstein-Barr nuclear antigen (EBNA1) is produced. EBNA1 is poorly immunogenic, enabling tumors to evade immune responses. Using a high-throughput screen, we identified decitabine as a potent inducer of immunogenic EBV antigens, including LMP1, EBNA2, and EBNA3C. Induction occurs at low doses and persists after removal of decitabine. Decitabine treatment of latency I EBV+ Burkitt lymphoma (BL) sensitized cells to lysis by EBV-specific cytotoxic T cells (EBV-CTLs). In latency I BL xenografts, decitabine followed by EBV-CTLs results in T-cell homing to tumors and inhibition of tumor growth. Collectively, these results identify key epigenetic factors required for latency restriction and highlight a novel therapeutic approach to sensitize EBV+ lymphomas to immunotherapy.

Humanized CD19 CAR-T cells in relapsed/refractory B-ALL patients who relapsed after or failed murine CD19 CAR-T therapy.

BACKGROUND: For CD19-positive relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL) after treatment with murine CD19 (mCD19) CAR-T, the reinfusion of mCD19 CAR-T cells may be ineffective due to anti-mouse single-chain variable fragment (scFv) antibody caused by mCD19 CAR. To overcome this immunogenicity, we applied humanized CD19 (hCD19) CAR-T cells to treat r/r B-ALL patients with prior mCD19 CAR-T therapy. METHODS: Nineteen pediatric and adult patients were included, 16 relapsed after and 3 were primarily resistant to mCD19 CAR-T. All patients presented with more than 5% blasts in bone marrow and/or extramedullary disease, and still showed CD19 antigen expression. Humanized CD19-CARs were lentiviral vectors carrying a second generation CAR with 4-1-BB co-stimulatory and CD3ζ signaling domains. Patient-derived cells were collected for producing CAR-T cells, the median dose of infused hCD19 CAR-T cells was 2.4 × 105/kg (range, 1.0-18.0 × 105/kg). RESULTS: hCD19 CAR-T resulted in a complete remission (CR) rate of 68% (13/19). Among 13 remission patients, 11 underwent allogeneic hematopoietic cell transplantation (allo-HCT) (3 were second HCT) and 10 remained in CR; the event-free survival rates at 12-18 months were 91% in 11 patients received following allo-HCT and 69% in all CR patients. Six cases had no response to hCD19 CAR-T, 3 died of disease progression; another 3 received salvage second transplantation, of them, 2 relapsed again (one died). Cytokine release syndrome (CRS) occurred in 95% (18/19) of patients, most CRS events were grade 1 and grade 2 (n = 17), there was only one grade 4 CRS. Two cases experienced grade 1 neurotoxicity. CONCLUSIONS: Humanized CD19 CAR-T cell therapy could be a treatment option for CD19-positive B-ALL patients who relapsed after or resisted prior murine CD19 CAR-T, hCD19 CAR-T followed by allo-HCT provided a longer remission in CR patients. Nevertheless, the prognosis of non-responders to hCD19 CAR-T remained dismal. TRIAL REGISTRATION: Chinese Clinical Trial Registry/WHO International Clinical Trial Registry ( ChiCTR1900024456 , URL: www.chictr.org.cn ); registered on July 12, 2019.

Improved survival of Burkitt lymphoma/leukemia patients: observations from Poland, 1999-2020.

The aim of this study was to estimate the survival of Polish Burkitt lymphoma/leukemia (BL) patients diagnosed between 1999 and 2017, considering multiple covariates and periods, to reflect changes in BL treatment. We identified all BL patients registered in the Polish National Cancer Registry in 1999-2017. Observed survival (OS) was evaluated deploying the life table method. Univariate and multivariate Cox proportional hazards regression models were fit to generate hazard ratios (HR) and the corresponding 95% confidence intervals (95% CI), describing the association between exposures (sex, age at the diagnosis, year of diagnosis, and region of residence) and time-to-event (death). Two-sided log-rank test was applied to assess the significance of exposures. Overall, 937 BL cases were included in the study (654 men and 283 women). Between the periods 1999-2005 and 2015-2017, the 3-year OS changed from 56.0% (95% CI 50.4 to 62.2%) to 73.8% (68.1 to 80.0%; P < 0.001), and the 5-year OS increased from 53.8% (48.2 to 60.0%) to 73.0% (67.1 to 79.3%; P < 0.001). The death HR was significantly higher in adolescents and young adults' (AYA) and adults' groups than in pediatric patients (HR = 3.00, 95% CI 2.05 to 4.39, P < 0.001, for AYA; and HR = 7.30, 5.14 to 10.3, P < 0.001, for adults). During the last two decades, the survival of Polish BL patients has been systematically improving. The death hazard ratio is most significantly associated with the patients' age at diagnosis and year of diagnosis, and not associated with sex or region of residence.

Impact of timing and precision of histopathological diagnosis on outcomes of patients with Burkitt lymphoma and high-grade B-cell lymphoma.

BACKGROUND: Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) are aggressive B-cell non-Hodgkin lymphomas (B-NHL) with a generally favorable prognosis after immunochemotherapy. The outcome of BL is superior to DLBCL. In 2016, a distinct group of lymphomas displaying characteristics of both BL and DLBCL (high grade B-cell lymphoma, HGBL) was introduced into the WHO classification. Histopathological discrimination of BL, DLBCL, and HGBL may be challenging. Data on the frequency of histopathological difficulties resulting in revision of the final diagnosis of BL/DLBCL/HGBL and its impact on the prognosis are limited. METHODS: We assessed histopathological features and clinical outcomes of 66 patients with suspected diagnosis of BL at the reporting institution between 2010 and 2020. RESULTS: The median age was 51 years (range 19-82) and final histopathological diagnosis revealed BL (n = 40), DLBCL (n = 12), or HGBL (n = 14). Patients with DLBCL and HGBL were either treated with DLBCL-directed (83.3% and 35.7%) or BL-directed (16.7% and 64.3%) protocols. Patients in whom diagnosis was revised from DLBCL to BL after initiation of DLBCL-directed treatment had a significantly inferior progression-free survival (PFS) than patients initially diagnosed with BL (p = 0.045), thus resembling rather the prognosis of DLBCL/HGBL. There was no difference between patients with DLBCL and HGBL, respectively, regarding PFS and OS (p = 0.38 and p = 0.27). CONCLUSION: These results suggest that timely and precise histopathological diagnosis as well as reference histopathological review of the underlying lymphoma is critical to determine up-front treatment strategies. Consequently, selection of more aggressive treatment protocols in case of difficulties with discrimination between DLBCL/HGBL/BL may be a reasonable approach.

Acute left ventricular insufficiency in a Burkitt Lymphoma patient with myocardial involvement and extensive local tumor cell lysis: a case report.

BACKGROUND: Burkitt lymphoma (BL) is a rare disease with the sporadic variant accounting for less than 1% of adult non-Hodgkin lymphomas. BL usually presents with an abdominal bulk, but extranodal disease affecting the bone marrow and central nervous system is common. Cardiac manifestations, however, are exceedingly rare, with less than 30 cases reported in the literature. CASE PRESENTATION: We report on a 54-year-old male patient with a six week-long history of paranasal sinus swelling, fatigue and dyspnea on exertion. Stage IV sporadic BL with extensive lymphonodal and cardiovascular involvement was diagnosed. Manifestations included supra- and infradiaphragmatic lymphadenopathy as well as infiltration of the aortic root, the pericardium, the right atrium and the right ventricle. EBV-reactivation was detected, which is uncommon in the sporadic subtype. After initial full-dose chemotherapy with very good BL control, the patient developed acute, but fully reversible cardiac insufficiency. Myocardial lymphoma involvement receded completely during the following two therapy cycles, while cardiac function periodically deteriorated shortly after chemotherapy administration and quickly recovered thereafter. Interestingly, the decline in cardiac function lessened with decreasing myocardial lymphoma manifestation. Once the cardiovascular BL infiltration was resolved, cardiac function remained stable throughout further treatment. Following seven cycles of chemotherapy and mediastinal radiation, the patient is now in continued complete remission. CONCLUSIONS: Although rare, cardiac involvement in BL can quickly become life-threatening due to rapid lymphoma doubling time and should therefore be considered at initial diagnosis. This case suggests an association between myocardial infiltration, chemotherapy associated tumor cell lysis and transient deterioration of cardiac function until the damage caused by the underlying lymphoma could be restored. While additional studies are needed to further elucidate the mechanisms of acute cardiac insufficiency due to lymphoma lysis in the infiltrated structures, prompt BL control and full recovery of the patient supports courageous treatment start despite extensive cardiovascular involvement.

Burkitt Lymphoma After Cardiac Transplantation: Therapeutic Considerations.

Postsolid organ transplant Burkitt lymphoma (PSOT-BL) is rare but more aggressive than other post-transplant lymphoproliferative disorders (PTLD). Little is known about optimal treatment and outcome of postcardiac transplant Burkitt lymphoma (BL). We report an 8-year-old boy with a history of heart transplant who developed Epstein-Barr virus positive, late-onset PSOT-BL. He was successfully treated with BL specific chemoimmunotherapy and cessation of baseline immunosuppression. In this pediatric case of PSOT-BL, the use of standard intensive pediatric based chemoimmunotherapy regimen without modifications was feasible, well tolerated and resulted in complete remission. Long-term toxicities need further study.

Self-driving armored CAR-T cells overcome a suppressive milieu and eradicate CD19+ Raji lymphoma in preclinical models.

Chimeric antigen receptor (CAR) T cells typically use a strong constitutive promoter to ensure maximal long-term CAR expression. However, recent evidence suggests that restricting the timing and magnitude of CAR expression is functionally beneficial, whereas constitutive CAR activation may lead to exhaustion and loss of function. We created a self-driving CD19-targeting CAR, which regulates its own function based on the presence of a CD19 antigen engaged by the CAR itself, by placing self-driving CAR19 constructs under transcriptional control of synthetic activator protein 1 (AP1)-nuclear factor κB (NF-κB) or signal transducer and activator of transcription (STAT)5 promoters. CD19 antigen-regulated expression was observed for self-driving AP1-NFκB-CAR19, with CAR19 upregulation within 18 h after exposure to target CD19, and corresponded to the level of tumor burden. Self-driving CAR-T cells showed enhanced tumor-dependent activation, expansion, and low exhaustion in vitro as compared to constitutively expressed EF1α and murine stem cell virus (MSCV) CARs and mediated tumor regression and survival in Raji-bearing NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. Long-term CAR function correlated with upregulated CAR expression within 24 h of exposure to tumor antigen. The self-driving AP1-NFκB-CAR19 circuit was also used to inducibly express dominant-negative transforming growth factor ß receptor II (TGFBRIIdn), which effectively countered the negative effects of TGF-ß on CAR-T activation. Thus, a self-driving CAR approach may offer a new modality to express CAR and auxiliary proteins by enhancing CAR-T functional activity and limiting exhaustion.

Paediatric Burkitt lymphoma patient-derived xenografts capture disease characteristics over time and are a model for therapy.

Burkitt lymphoma (BL) accounts for almost two-thirds of all B-cell non-Hodgkin lymphoma (B-NHL) in children and adolescents and is characterised by a MYC translocation and rapid cell turnover. Intensive chemotherapeutic regimens have been developed in recent decades, including the lymphomes malins B (LMB) protocol, which have resulted in a survival rate in excess of 90%. Recent clinical trials have focused on immunochemotherapy, with the addition of rituximab to chemotherapeutic backbones, showing encouraging results. Despite these advances, relapse and refractory disease occurs in up to 10% of patients and salvage options for these carry a dismal prognosis. Efforts to better understand the molecular and functional characteristics driving relapse and refractory disease may help improve this prognosis. This study has established a paediatric BL patient-derived xenograft (PDX) resource which captures and maintains tumour heterogeneity, may be used to better characterise tumours and identify cell populations responsible for therapy resistance.