A novel costimulatory molecule gene-modified leukemia cell-derived exosome enhances the anti-leukemia efficacy of DC vaccine in mouse models.

OBJECTIVES: Leukemia cell-derived exosomes (LEXs), carrying leukemia cell-specific antigens, can serve as a source of antigen for dendritic cell (DC) vaccine loading. However, LEX-targeted DC-based vaccines have demonstrated limited antitumor immune effects in clinical trials, attributed to the low immunogenicity of LEXs and the scant levels of costimulatory molecules on DCs. The costimulatory molecules CD80 and CD86, which are crucial to DC function, play a significant role in enhancing immune efficacy. In this study, we explored the anti-leukemia immune response of costimulatory molecule gene-modified LEX-targeted DCs (LEX-8086) in vitro and in animal models. METHODS: DCs were incubated with LEX-8086 to produce LEX-8086-targeted DCs (DCsLEX-8086). ELISA, cytotoxicity assays and flow cytometry utilized to assess the antitumor efficacy of DCsLEX8086 in vitro. Flow cytometry was used to evaluate the immunomodulatory function of DCsLEX8086 in animal models. RESULTS: Our findings indicated that LEX-8086 enhanced the maturation and antigen-presenting ability of DCs. Immunization with DCsLEX8086 significantly activated CD8+ T cells and boosted the CTL response in vitro. More importantly, DCsLEX-8086 effectively suppressed tumor growth and exerted anti-leukemia effects in both prophylactic and therapeutic animal models. Furthermore, DCsLEX-8086 promoted the proportion of CD4+ T cells, CD8+ T cells and M1 macrophages in the tumor environments both prophylactically and therapeutically. Treatment with DCsLEX-8086 showed no significant difference in the levels of M2 macrophages but decreased the proportion of Tregs within the tumor bed during therapeutic experiments. CONCLUSION: The results suggested that DCsLEX-8086 induces a more effective anti-leukemia immunity compared to DCsLEX-null in vivo and in vitro. DCsLEX-8086 might achieve antitumor effects by elevating the numbers of CD4+ T cells, CD8+ T cells, and M1 macrophages in tumors. Our findings indicate that DCsLEX-8086 could be leveraged to develop a new, highly effective vaccine for anti-leukemia immunity.

Enhancer of Zeste Homolog 2 Inhibitor SHR2554 in Relapsed or Refractory Peripheral T-cell Lymphoma: Data from the First-in-Human Phase I Study.

PURPOSE: Patients with peripheral T-cell lymphomas (PTCL) in the relapsed or refractory (r/r) setting have only a limited number of therapies available, and the prognosis is extremely poor. SHR2554 is an oral inhibitor against EZH2, a rational therapeutic target for lymphomas. PATIENTS AND METHODS: This was a multicenter, two-part, phase I study of SHR2554 in r/r mature lymphoid neoplasms. In part I, 350 mg twice daily was established as the recommended phase II dose (RP2D) based on the findings during dose escalation and expansion; subsequently, selected lymphoma subtypes were recruited in clinical expansion cohorts to receive SHR2554 at RP2D. Here, we provide an in-depth assessment of SHR2554 at RP2D in subpopulation with r/r PTCL. RESULTS: Twenty-eight patients were included for analysis (17 angioimmunoblastic T-cell lymphoma and 11 not otherwise specified). Eighteen (64%) patients had received ≥2 lines of previous anticancer therapies. The objective response rate was 61% [95% confidence interval (CI), 41-78]. Responses were still ongoing in 59% (10/17) of the responders; estimated median duration of response was 12.3 months (95% CI, 7.4-not reached). Median progression-free survival was 11.1 months (95% CI, 5.3-22.0), and 12-month overall survival rate was 92% (95% CI, 72-98). The most common grade 3 or 4 treatment-related adverse events were decreased platelet count [nine (32%)] as well as decreased white blood cell count, decreased neutrophil count, and anemia [four (14%) for each]. No treatment-related deaths were reported. CONCLUSIONS: This extended follow-up analysis further supports SHR2554 as a therapeutic opportunity for patients with r/r PTCL.

Selinexor With Anti-PD-1 Antibody as a Potentially Effective Regimen for Patients With Natural Killer/T-Cell Lymphoma Failing Prior L-Asparaginase and PD-1 Blockade.

BACKGROUND: Natural killer/T-cell lymphoma (NKTCL) is a rare and heterogeneous tumor type of non-Hodgkin's lymphoma (NHL) with a poor clinical outcome. There is no standardized salvage treatment failing l-asparaginase-based regimens. Here we report our retrospective results of the combined use of selinexor and PD-1 blockade (tislelizumab) in 5 patients with NKTCL who had exhausted almost all available treatments. PATIENTS AND METHODS: A total of 5 patients with relapsed/refractory(R/R) NK/T-cell lymphomas failing prior l-asparaginase and anti-PD-1 antibody were retrospectively collected. They were treated with at least one cycle of XPO1 inhibitor plus the same anti-PD-1 antibody. Anti-PD-1 antibody (Tislelizumab) was administrated at 200 mg on day 1 every 3 weeks and selinexor doses and schedules ranged from 40 mg weekly for 2 weeks per 21-day cycle to 60 mg weekly per cycle. RESULTS: Five patients with relapsed NKTCL with extensive organ involvement including 4 central nervous system (CNS) infiltration patients were included. Four patients achieved objective responses including 3 complete responses (CR) and 1 partial response (PR). After a median follow-up time of 14.5 (range, 5-22) months, 1 patient was still in remission with CR, and the other 4 patients discontinued due to disease progression with a median progression-free survival (PFS) of 6 months and median overall survival (OS) of 12 months. Four patients with CNS involvement achieved a median OS of 8 months. Our data suggest that selinexor in combination with an anti-PD-1 antibody is a promising small molecule and immunotherapy combination regimen for patients with relapsed or refractory NKTCL.

Mesenchymal stem cell-derived exosomes can alleviate GVHD and preserve the GVL effect in allogeneic stem cell transplantation animal models.

Background: Mesenchymal stem cells (MSCs) can alleviate graft-versus-host disease (GVHD) in hematopoietic stem cell transplantation (HSCT). MSCs-derived exosomes (MEXs) can mirror the biological function of their parent cells. Whether MEXs can alleviate GVHD like their parent cells or not is unclear. In this study, we investigate the effects of MEXs on GVHD and graft-versus-leukemia (GVL) effect in vitro and in HSCT animal models. Method: MSCs were produced using bone marrow mononuclear cells (MNCs), and MEXs were separated from the supernatants of MSCs. Electron microscopy, western blot, and nanoparticle tracking analysis (NTA) were used to determine the characteristics of MEXs. The immunomodulatory function of MEXs and their effects on GVHD and GVL were examined in vitro and in vivo. Result: Like other cell-type derived exosomes, our data revealed that MEXs were also disc-shaped vesicles with a diameter of 100-200 nm under electron microscopy and were positive for the exosomal hallmark proteins. MEXs can notably inhibit the expression of costimulatory molecules and functional cytokine secretion of dendritic cells (DCs). Meanwhile, MEXs can exert suppressive effects on T lymphocyte proliferation and activation. Moreover, MEXs can also encourage the polarization of macrophages toward the M2 type. In animal HSCT models, MEXs can promote the differentiation of Treg cells in spleens, decrease the GVHD score, increase the survival rate of mice, and preserve the cytotoxic antileukemia effects of CD8+ T lymphocytes from recipient mice. Conclusion: These findings showed that MEXs exert their effects by inhibiting the immunomodulatory function of DCs, macrophages, and T lymphocytes. In the animal model, MEXs ameliorate the clinical symptoms of GVHD, while maintaining the antitumor effects of CD8+ T lymphocytes. Therefore, it can be inferred that MEXs can separate GVHD from GVL in HSCT. Our study suggests that MEXs have broad clinical application potential in the prevention and treatment of GVHD in HSCT in the near future.

Treating relapsed/refractory mature T- and NK-cell neoplasms with tislelizumab: a multicenter open-label phase 2 study.

Patients with relapsed/refractory (R/R) mature T- and natural killer (NK)-cell neoplasms lack effective treatments after failure of standard therapies. This phase 2 study evaluated the efficacy and safety of the programmed cell death protein 1 inhibitor tislelizumab in these patients. Seventy-seven patients were treated with 200 mg tislelizumab every 3 weeks. Twenty-two patients with extranodal NK-/T-cell lymphomas were enrolled in cohort 1; 44 patients with peripheral T-cell lymphoma (PTCL) were enrolled in cohort 2 (21 patients had PTCL not otherwise specified, 11 patients had angioimmunoblastic T-cell lymphoma, and 12 patients had anaplastic large-cell lymphoma). Cohort 3 comprised 11 patients with cutaneous T-cell lymphoma, of which 8 patients had mycosis fungoides (MF) and 3 had Sézary syndrome. Of the 77 patients, 76.6% had advanced-stage disease, 51.9% had refractory disease, and 49.4% received ≥3 prior systemic regimens. Promising efficacy was observed in cohort 3 (median follow-up [FU], 16.6 months; overall response rate [ORR], 45.5%; complete response [CR], 9.1%; median duration of response [DOR], 11.3 months; median progression-free survival, 16.8 months; median overall survival, not reached). Modest efficacy was observed in cohort 1 (median FU, 8.4 months; ORR, 31.8%; CR, 18.2%; median DOR, not reached) and cohort 2 (median FU, 9.3 months; ORR, 20.5%; CR, 9.1%; median DOR, 8.2 months). Most treatment-related adverse events were grade 1 or 2, and the safety profile was consistent with the known safety profile of tislelizumab. In conclusion, tislelizumab was well tolerated, achieving modest efficacy in R/R mature T- and NK-cell neoplasms, with some long-lasting remissions. This trial was registered at www.clinicaltrials.gov as #NCT03493451.

Sugemalimab Monotherapy for Patients With Relapsed or Refractory Extranodal Natural Killer/T-Cell Lymphoma (GEMSTONE-201): Results From a Single-Arm, Multicenter, Phase II Study.

PURPOSE: Relapsed or refractory extranodal natural killer/T-cell lymphoma (R/R ENKTL) is a rare and aggressive type of non-Hodgkin lymphoma with limited treatment options. This phase II study evaluated the efficacy and safety of sugemalimab, an anti-PD-L1 monoclonal antibody, in R/R ENKTL. METHODS: Eligible patients received sugemalimab 1,200 mg intravenously once every 3 weeks for up to 24 months or until progression, death, or study withdrawal. The primary end point was objective response rate (ORR) assessed by an independent radiologic review committee. Key secondary end points included ORR assessed by the investigators, complete response rate, duration of response, and safety. RESULTS: At the data cutoff (February 23, 2022), 80 patients were enrolled and followed for a median of 18.7 months. At baseline, 54 (67.5%) had stage IV disease and 39 (48.8%) had received ≥2 lines of prior systemic therapy. Independent radiologic review committee-assessed ORR was 44.9% (95% CI, 33.6 to 56.6); 28 (35.9%) patients achieved a complete response and seven (9.0%) achieved a partial response, with a 12-month duration of response rate of 82.5% (95% CI, 62.0 to 92.6). Investigator-assessed ORR was 45.6% (95% CI, 34.3 to 57.2), and 24 (30.4%) patients achieved a complete response. Most treatment-emergent adverse events were grade 1-2 in severity, and grade ≥ 3 events were reported in 32 (40.0%) patients. CONCLUSION: Sugemalimab showed robust and durable antitumor activity in R/R ENKTL. Treatment was well tolerated with expected safety profile for this drug class.

A novel costimulatory molecule gene-modified leukemia cell-derived exosome-targeted CD4+ T cell vaccine efficiently enhances anti-leukemia immunity.

Previous studies demonstrated that CD4+ T cells can uptake tumor antigen-pulsed dendritic cell-derived exosomes (DEXO), which harbor tumor antigen peptide/pMHC I complex and costimulatory molecules and show potent effects on inducing antitumor immunity. However, in preliminary study, CD4+ T cells targeted by leukemia cell-derived exosomes (LEXs) did not show the expected effects in inducing effective anti-leukemia immunity, indicating that LEX is poorly immunogenetic largely due to an inadequate costimulatory capacity. Therefore, LEX-based anti-leukemia vaccines need to be optimized. In this study, we constructed a novel LEX-based vaccine by combining CD4+ T cells with costimulatory molecules gene-modified LEXs, which harbor upregulated CD80 and CD86, and the anti-leukemia immunity of CD80 and CD86 gene-modified LEX-targeted CD4+ T cells was investigated. We used lentiviral vectors encoding CD80 and CD86 to successfully transduced the L1210 leukemia cells, and the expression of CD80 and CD86 was remarkably upregulated in leukemia cells. The LEXs highly expressing CD80 and CD86 were obtained from the supernatants of gene-transduced leukemia cells. Our data have shown that LEX-CD8086 could promote CD4+ T cell proliferation and Th1 cytokine secretion more efficiently than control LEXs. Moreover, CD4+ TLEX-CD8086 expressed the acquired exosomal costimulatory molecules. With acquired costimulatory molecules, CD4+ TLEX-CD8086 can act as APCs and are capable of directly stimulating the leukemia cell antigen-specific CD8+ CTL response. This response was higher in potency compared to that noted by the other formulations. Furthermore, the animal study revealed that the CD4+ TLEX-CD8086 significantly inhibited tumor growth and prolonged survival of tumor-bearing mice than other formulations did in both protective and therapeutic models. In conclusion, this study revealed that CD4+ TLEX-CD8086 could effectively induce more potential anti-leukemia immunity than LEX-CD8086 alone, suggesting that the utilization of a costimulatory molecule gene-modified leukemia cell-derived exosome-targeted CD4+ T cell vaccine may have promising potential for leukemia immunotherapy.

[Research Progress on Immunomodulatory Activity and Clinical Application of Mesenchymal Stem Cells-Derived Extracellular Vesicles--Review].

Mesenchymal stem cells (MSC) have been widely used in tissue regeneration and treatment graft versus host disease (GVHD) and immune diseases due to their self-renewal, multi-differentiation and immunoregulatory potential. However, more and more scholars begin to put weight on the MSC -derived extracellular vesicles (MSC-EV) for its regulation of inflammation and immunity. MSC-EV can activate the relevant signal pathways and regulate the function and biological behaviors of cells via acting on target cells and mediating communication between cells. MSC-EV has important potential clinical applications for its powerful immunomodulatory and hematopoietic regulatory functions. It is considered as a potential therapeutic tool to treat autoimmune diseases and GVHD. This paper reviewed the immunomodulatory activity of MSC-EV as well as the research progress of MSC-EV in hematopoietic stem cell transplantation, and discussed its potential clinical applications in the future.

SHR2554, an EZH2 inhibitor, in relapsed or refractory mature lymphoid neoplasms: a first-in-human, dose-escalation, dose-expansion, and clinical expansion phase 1 trial.

BACKGROUND: Dysregulation of EZH2 has a crucial role in lymphomagenesis. We did a first-in-human study to assess the safety, pharmacokinetics, pharmacodynamics, and preliminary clinical activity of SHR2554, an oral EZH2 inhibitor, in patients with relapsed or refractory mature lymphoid neoplasms, including B-cell lymphomas, T-cell lymphomas, and classical Hodgkin lymphoma. METHODS: This was a multicentre, dose-escalation, dose-expansion, and clinical expansion phase 1 study done at 13 hospitals in China. Eligible patients had histologically or cytologically confirmed mature lymphoid neoplasms that had relapsed or were refractory to standard systemic therapies or had no standard-of-care. The study included a dose-escalation phase, at doses of SHR2554 from 50 mg to 800 mg twice daily; a dose-expansion phase, at two selected doses; and a subsequent clinical expansion phase at the recommended phase 2 dose in selected tumours. Primary endpoints were the safety, maximum tolerated dose, and recommended phase 2 dose. Objective response rate was a secondary endpoint. Safety and activity were assessed in all patients who received at least one dose of SHR2554 and had at least one post-baseline evaluation. This study is registered with ClinicalTrials.gov, NCT03603951, and follow-up is ongoing. FINDINGS: Between Aug 14, 2018, and July 13, 2021, 113 patients received SHR2554. At data cutoff (Sept 10, 2021), the median follow-up duration was 7·0 months (IQR 3·7-12·0). 71 (63%) patients were men and 42 (37%) were women, 110 (97%) were of Han ethnicity and 3 (3%) of other ethnicities, and 53 (47%) had received three or more lines of previous anticancer therapies. Dose-limiting toxicities occurred in two (67%) of three patients who received 400 mg SHR2554 twice daily and one (17%) of six patients who received 350 mg SHR2554 twice daily. The maximum tolerated dose and recommended phase 2 dose was determined to be 350 mg twice daily. The most common grade 3 or 4 treatment-related adverse events in all 113 patients were decreased platelet count (20 [18%]), decreased neutrophil count (ten [9%]), decreased white blood cell count (nine [8%]), and anaemia (seven [6%]). 18 (16%) patients had serious treatment-related adverse events. Two patients (2%) died due to treatment-related adverse events: one (1%) due to skin infection and toxic epidermal necrolysis and one (1%) due to respiratory failure. 107 (95%) of the 113 enrolled patients had post-baseline assessments for tumour response and were included in the activity analysis. 46 (43%; 95% CI 33-53) of these 107 patients had an overall response. INTERPRETATION: SHR2554 showed an acceptable safety profile and promising antitumour activity in patients with relapsed or refractory lymphomas, providing evidence for future investigations. FUNDING: Jiangsu Hengrui Pharmaceuticals. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

Induction with MEDA regimen and consolidation with Auto-HSCT for stage IV NKTCL patients: A prospective multicenter study.

Optimal treatment strategies for natural killer/T-cell lymphoma (NKTCL) patients with stage IV disease have not been well defined. In this prospective phase 2 study, we evaluated the treatment using MEDA (methotrexate, etoposide, dexamethasone and pegaspargase) as induction chemotherapy and autologous hematopoietic stem cell transplantation (Auto-HSCT) for consolidation. Patients with stage IV disease without prior L-asparaginase-based chemotherapy were eligible. Four cycles of MEDA were administered as induction treatment. Patients with complete response (CR, necessary to have complete metabolic remission of PET/CT, negative plasma EBV-DNA and negative EBER staining of bone marrow biopsy tissue) were consolidated by Auto-HSCT. A total of 53 patients were enrolled. The overall response (OR) rate and CR rate after four cycles of MEDA chemotherapy were 75.5% and 56.6%, respectively. Among them, 25 patients underwent Auto-HSCT. The 4-year overall survival (OS) rate and progression-free survival (PFS) rate were 58.0% (95% CI, 43.4%-70.0%) and 43.4% (95% CI, 29.9%-56.1%), respectively. Patients who underwent Auto-HSCT had a 4-year OS rate of 92.0% (95% CI, 71.6%-97.9%) and a 4-year PFS rate of 80.0% (95% CI, 58.4%-91.1%). Grade 3/4 neutropenia and thrombocytopenia occurred in 28.3% and 17.0% of the patients, respectively. MEDA chemotherapy is an effective induction regimen with reduced grade 3/4 hematological toxicities for stage IV NKTCL. Consolidation with Auto-HSCT can be considered as a potential approach to improve the long-term survival of CR patients after induction treatment.

Enhancing the anti-leukemia immunity of acute lymphocytic leukemia-derived exosome-based vaccine by downregulation of PD-L1 expression.

Cell-released nanovesicles can induce anti-leukemia immunity. Leukemia cell-derived exosomes (LEXs) are promising anti-tumor vaccine components for cancer immunotherapy. Nonetheless, LEX-based vaccines show modest potency in vivo, likely due to the presence of immunosuppressive PD-L1 proteins in the exosomes. We hypothesized that targeting exosomal PD-L1 could optimize LEX-based vaccines. To test this hypothesis, we compared the capacity of exosomes derived from PD-L1-silenced acute lymphocytic leukemia-derived leukemia cells (LEXPD-L1si) and non-modified exosomes to induce anti-leukemia immunity. Lentivirus-mediated PD-L1 shRNA was used to downregulate PD-L1 expression in parental leukemia cells and LEXs. LEXPD-L1si were characterized by electron microscopy, Western blotting, nanoparticle tracking analysis and flow cytometry, and their anti-leukemia immune effects were tested on immune cells and in animal models. In the present study, lentivirus-mediated PD-L1 shRNA successfully downregulated PD-L1 expression in parental leukemia cells and in LEXs. LEXPD-L1si induced better DC maturation and subsequently enhanced T cell activation, as compared with non-modified LEXs. Consistently, immunization with LEXPD-L1si induced greater T cell proliferation and Th1 cytokine release. LEXPD-L1si was a more potent inducer of antigen-specific cytotoxic lymphocyte (CTL) response. Finally, we vaccinated DBA/2 mice with exosome formulations to test their ability to induce both protective and therapeutic anti-tumor CTL responses in vivo. Vaccination with LEXPD-L1si strongly inhibited tumor growth and prolonged survival of immunized mice. Downregulation of exosomal PD-L1 expression in LEXs effectively induces more potent anti-leukemia immunity. Therefore, our strategy for optimizing LEX-based vaccine has a potential application in leukemia immunotherapy.

GELAD chemotherapy with sandwiched radiotherapy for patients with newly diagnosed stage IE/IIE natural killer/T-cell lymphoma: a prospective multicentre study.

Early-stage natural killer/T-cell lymphoma (NK/TCL) patients usually receive a combination of chemotherapy and radiotherapy, but the optimal treatment approach has not yet been established. This study aimed to investigate the efficacy and safety profile of a novel chemotherapy regimen and sandwiched radiotherapy in early-stage NK/TCL. Patients with newly diagnosed stage IE/IIE disease were eligible. Patients were initially treated with two courses of the GELAD regimen (gemcitabine 1·0 g/m2 day 1, etoposide 60 mg/m2 days 1-3, pegaspargase 2000 units/m2 day 4, and dexamethasone 40 mg days 1-4), followed by intensity-modulated radiotherapy (IMRT; 50-56 Gy in 25-28 fractions) and two additional courses of GELAD chemotherapy. A total of 52 patients were enrolled. The overall response rate and complete response rate per Lugano 2014 criteria were 94·2% and 92·3% respectively. With a median follow-up of 32 months, the estimated four-year overall survival rate and progression-free survival rate were 94·2% [95% confidence interval (CI), 83·2% to 93·1%] and 90·4% (95% CI, 78·4% to 95·9%) respectively. The most common adverse events were related to pegaspargase. Haematological toxicities were mild, with grade 3/4 neutropenia in 15·4% of patients. Our study provides a new approach with high activity and improved safety for the treatment of early-stage NK/TCL patients. This study was registered at www.clinicaltrials.gov as NCT02733458.

Inhibition of mitochondrial complex III induces differentiation in acute myeloid leukemia.

Although acute myeloid leukemia (AML) is a highly heterogeneous disease with diverse genetic subsets, one hallmark of AML blasts is myeloid differentiation blockade. Extensive evidence has indicated that differentiation induction therapy represents a promising treatment strategy. Here, we identified that the pharmacological inhibition of the mitochondrial electron transport chain (ETC) complex III by antimycin A inhibits proliferation and promotes cellular differentiation of AML cells. Mechanistically, we showed that the inhibition of dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme in de novo pyrimidine biosynthesis, is involved in antimycin A-induced differentiation. The activity of antimycin A could be reversed by supplement of excessive amounts of exogenous uridine as well as orotic acid, the product of DHODH. Furthermore, we also found that complex III inhibition exerts a synergistic effect in differentiation induction combined with DHODH inhibitor brequinar as well as with the pyrimidine salvage pathway inhibitor dipyridamole. Collectively, our study uncovered the link between mitochondrial complex III and AML differentiation and may provide further insight into the potential application of mitochondrial complex III inhibitor as a mono or combination treatment in differentiation therapy of AML.

Enhanced immunogenicity of leukemia-derived exosomes via transfection with lentiviral vectors encoding costimulatory molecules.

BACKGROUND: Tumor cell-derived exosomes (TEXs) have been widely used to induce antitumor immune responses in animal models and clinical trials. Similarly, leukemia cell-derived exosomes (LEXs) can induce antileukemia immune responses in animal models. However, the antileukemia immunity induced by LEXs is less effective, which may be due to an inadequate costimulatory capacity. METHODS: In this study, we transduced L1210 leukemia cells with a lentiviral vector encoding two B7 costimulatory molecules (CD80, CD86) and obtained LEXs that highly expressed CD80 and CD86. The antileukemia immune response derived from these LEXs was examined in vitro and in vivo in animal models. RESULTS: We found that B7 gene-modified LEXs, including LEX-CD80, LEX-CD86, and LEX-8086, could significantly boost the expression of CD80 and CD86 in dendritic cells (DCs) and promote the secretion of functional cytokines such as TNF-α and IL-12. Moreover, these B7 gene-modified LEXs, particularly LEX-CD8086, could effectively induce CD4+ T cell proliferation, Th1 cytokine secretion, and an antigen-specific anti-leukemia cytotoxic T lymphocyte (CTL) response. Additional animal studies indicated that immunization with B7 gene-modified LEXs, in particular LEX-CD8086, could significantly retard tumor growth compared to the control LEXnull group. CONCLUSIONS: This study sheds light on the feasibility of obtaining LEXs that overexpress costimulatory molecules via genetically modified leukemia cells, thereby enhancing their anti-leukemia immunity and providing a potential therapeutic strategy that contributes to leukemia immunotherapy.

Pre-transplant MRD negativity predicts favorable outcomes of CAR-T therapy followed by haploidentical HSCT for relapsed/refractory acute lymphoblastic leukemia: a multi-center retrospective study.

BACKGROUND: Consolidative allogeneic hematopoietic stem cell transplantation is a controversial option for patients with relapsed/refractory acute lymphoblastic leukemia after chimeric antigen receptor T cell (CAR-T) therapy. We performed a multicenter retrospective study to assess whether patients can benefit from haploidentical hematopoietic stem cell transplantation after CAR-T therapy. METHODS: A total of 122 patients after CAR-T therapy were enrolled, including 67 patients without subsequent transplantation (non-transplant group) and 55 patients with subsequent haploidentical hematopoietic stem cell transplantation (transplant group). Long-term outcome was assessed, as was its association with baseline patient characteristics. RESULTS: Compared with the non-transplant group, transplantation recipients had a higher 2-year overall survival (OS; 77.0% versus 36.4%; P < 0.001) and leukemia-free survival (LFS; 65.6% versus 32.8%; P < 0.001). Multivariate analysis showed that minimal residual disease (MRD) positivity at transplantation is an independent factor associated with poor LFS (P = 0.005), OS (P = 0.035), and high cumulative incidence rate of relapse (P = 0.045). Pre-transplant MRD-negative recipients (MRD- group) had a lower cumulative incidence of relapse (17.3%) than those in the non-transplant group (67.2%; P < 0.001) and pre-transplant MRD-positive recipients (MRD+ group) (65.8%; P = 0.006). The cumulative incidence of relapse in MRD+ and non-transplant groups did not differ significantly (P = 0.139). The 2-year LFS in the non-transplant, MRD+, and MRD- groups was 32.8%, 27.6%, and 76.1%, respectively. The MRD- group had a higher LFS than the non-transplantation group (P < 0.001) and MRD+ group (P = 0.007), whereas the LFS in the MRD+ and non-transplant groups did not differ significantly (P = 0.305). The 2-year OS of the MRD- group was higher than that of the non-transplant group (83.3% versus 36.4%; P < 0.001) but did not differ from that of the MRD+ group (83.3% versus 62.7%; P = 0.069). The OS in the non-transplant and MRD+ groups did not differ significantly (P = 0.231). CONCLUSION: Haploidentical hematopoietic stem cell transplantation with pre-transplant MRD negativity after CAR-T therapy could greatly improve LFS and OS in patients with relapsed/refractory acute lymphoblastic leukemia. TRIAL REGISTRATION: The study was registered in the Chinese clinical trial registry (ChiCTR1900023957).

Successful treatment of diffuse large B-cell lymphoma with secondary hemophagocytic lymphohistiocytosis by R-CHOP-E regimen: a case report.

Hemophagocytic lymphohistiocytosis (HLH) is a rare fatal clinical syndrome characterized by a hyperinflammatory condition caused by aberrantly activated macrophages and cytotoxic T cells, resulting in a cytokine storm and organ impairment. Lymphoma, especially B-cell lymphoma in Japan, is a common trigger of secondary HLH. In China, however, most cases of HLH secondary to lymphoma occur in patients with T-cell/natural killer-cell lymphoma or Hodgkin`s lymphoma; HLH is relatively uncommon in patients with B-cell non-Hodgkin's lymphoma. We herein describe a man with diffuse large B-cell lymphoma (DLBCL) and secondary HLH who was successfully treated by R-CHOP-E chemotherapy. All symptoms resolved and laboratory indications of HLH normalized, and complete remission of the lymphoma was achieved. This rare case highlights not only the possibility of HLH secondary to DLBCL but also the importance of early initiation of R-CHOP-E chemotherapy.

Enhanced alleviation of aGVHD by TGF-ß1-modified mesenchymal stem cells in mice through shifting MΦ into M2 phenotype and promoting the differentiation of Treg cells.

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is the only curative method in treating haematologic malignant diseases. Graft-versus-host disease (GVHD) is a common complication post-allo-HSCT, which can be life-threatening. Mesenchymal stem cells (MSCs) as an adult stem cell with immunoregulatory function have demonstrated efficacy in steroid resistant acute GVHD (aGVHD). However, the outcome of aGVHD treated with MSCs in clinical trials varied and its underlying mechanism is still unclear. TGF-ß1 is a potent cytokine, which plays a key role in immunoregulation. In the present study, we firstly transduced the lentivirus vector containing TGF-ß1 gene with mouse bone marrow-derived MSCs. Then, we investigated the immunosuppressive effect of TGF-ß1 gene-modified MSCs on lymphocytes in vitro and its preventive and therapeutical effects on murine aGVHD model in vivo. Murine MSC was successfully isolated and identified. TGF-ß1 was efficiently transduced into mouse MSCs, and high level TGF-ß1 was detected. MSC-TGF-ß1 shared the same morphology and immunotypic features of normal MSC. In vitro, MSC-TGF-ß1 showed enhanced immunosuppressive function on lymphocyte proliferation. In vivo, MSC-TGF-ß1 showed enhanced amelioration on the severity of aGVHD both in prophylactic and therapeutic murine models. Finally, the macrophages (MØs) derived from MSC-TGF-ß1-treated mice showed a remarkably increasing of anti-inflammatory M2-like phenotype. Furthermore, the differentiation of CD4+ CD25+ Foxp3+ Treg cells was significantly increased in MSC-TGF-ß1-treated group. Taken together, we proved that MSC-TGF-ß1 showed enhanced alleviation of aGVHD severity in mice by skewing macrophages into a M2 like phenotype or increasing the proportion of Treg cells, which opens a new frontier in the treatment of aGVHD.

A-1210477, a selective MCL-1 inhibitor, overcomes ABT-737 resistance in AML.

Acute myeloid leukemia (AML) is one of the most common hematological malignancies. It is difficult to treat since it easily develops resistance to therapeutic drugs. Myeloid cell leukemia 1 (MCL-1), BCL-2 and BCL-XL, which belong to the anti-apoptotic group of proteins in the BCL-2 family, are overexpressed in AML. The effects of inhibitors that target anti-apoptotic proteins of the BCL-2 family in AML were evaluated in the present study. MCL-1 protein levels of HL60, MOLM13, OCI-AML3 and MV4-11 cell lines were investigated. Furthermore, following treatment with MCL-1-selective antagonist A-1210477 and/or BCL-2/BCL-XL antagonist ABT-737, cell viability was detected. The chimera rate of human CD45(+) cells of bone marrow from mouse models was analyzed via flow cytometry and immunohistochemistry using murine tissues (lung, spleen and liver). The data revealed that the HL-60 cell line, which exhibited a low MCL-1 protein level, and MOLM-13 and MV4-11 cell lines, whose MCL level was intermediate, were sensitive to ABT-737, whereas OCI-AML3 cells, which exhibited a high MCL-1 level, were insensitive to ABT-737. However, multiple AML mouse models and AML cell lines were sensitive to the MCL-1-selective antagonist A-1210477. The results of the present study indicated that the MCL-1-selective antagonist could overcome the resistance to the BCL-2/BCL-XL antagonist (ABT-737) in vitro and in vivo.

rhTPO combined with chemotherapy and G-CSF for autologous peripheral blood stem cells in patients with refractory/relapsed non-Hodgkin's lymphoma.

OBJECTIVE: The mobilization and collection of sufficient autologous peripheral blood stem cells (APBSCs) are important for the fast and sustained reconstruction of hematopoietic function after autologous transplantation. This study aims to evaluate the mobilization effect and safety of thrombopoietin (TPO) combined with chemotherapy + G-CSF for APBSCs in patients with refractory/relapsed non-Hodgkin's lymphoma. METHODS: A total of 78 patients were included in the present study. After receiving mobilization chemotherapy, all patients were randomly divided into two groups: TPO group (n=40), patients were given subcutaneous injection of rhTPO + G-CSF, and control group (n=38), patients were given subcutaneous injection of G-CSF. The primary endpoint was the total number of obtained CD34+ cells. The secondary endpoints were the mononuclear cell count, the proportion of target and minimum mobilization, the engraftment time of neutrophils and platelets after APBSCT, the number of platelet and red blood cell infusions, the incidence of infectious fever and fever duration, and TPO-related side effects in patients. RESULTS: TPO participation significantly increased the total CD34+ cell count. A higher proportion of patients in the TPO group achieved the minimum and target CD34+ cells, when compared to the control group. TPO-related adverse events were not observed in either of these groups. In addition, there were no significant differences in engraftment time, the number of platelet and red blood cell transfusions, the incidence of infectious fever, and fever duration between these two groups. CONCLUSION: TPO combined with chemotherapy + G-CSF can safely and effectively enhance the mobilization effect for APBSCs in patients with refractory/relapsed non-Hodgkin's lymphoma.