Clinical characteristics and prognosis of patients with diffuse large B-cell lymphoma

Objective·To analyze the clinical characteristics and prognostic risk factors of patients with diffuse large B-cell lymphoma (DLBCL), and evaluate the prognostic effects of autologous stem cell transplantation (ASCT) and rituximab maintenance therapy on DLBCL patients.Methods·The clinical data of 160 patients with DLBCL who were first diagnosed by pathology and immunotyping were collected from the Department of Hematology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine from January 2015 to January 2020, and the risk factors affecting the efficacy and prognosis of patients were analyzed. Moreover, the clinical characteristics of patients with relapsed/refractory DLBCL and the effect of salvage ASCT on overall survival (OS) were assessed. For those high-risk patients who achieved complete remission (CR) in the interim assessment, the impact of ASCT and rituximab maintenance therapy on survival outcomes was further assessed.Results·Patients with initial age of treatment >60 years (P=0.005), International Prognostic Index (IPI) 3‒5 scores (P=0.032), low albumin level (P=0.001) and anemia (P=0.007) had poor efficacy. Multivariate analysis showed that the initial age of treatment >60 years (HR=2.788, 95%CI 1.575‒4.936, P=0.000), non-GCB subtype (HR=2.230, 95%CI 1.150‒4.324, P=0.018), elevated lactate dehydrogenase level (HR=2.064, 95%CI 1.006‒4.234, P=0.048) and low albumin level (HR=2.052, 95% CI 1.169‒3.602, P=0.012) were the independent risk factors for progression-free survival (PFS). The initial age of treatment >60 years (HR=2.269, 95% CI 1.060‒4.860, P=0.035) and IPI scores of 3 to 5 (HR=2.557, 95%CI 1.132‒5.778, P=0.024) were independent factors affecting OS. For patients with relapsed/refractory DLBCL, salvage ASCT was found to significantly improve the prognosis of these patients and was a protective factor for the death event of patients (P=0.030). For patients in the high-risk group who achieved CR in the interim evaluation after chemotherapy, there were no deaths in patients on maintenance therapy with consolidation ASCT and rituximab to the end point of follow-up; however, it did not prolong the OS of the patients (P>0.05).Conclusion·In patients with relapsed/refractory DLBCL, salvage ASCT can significantly prolong the OS, whereas in the high-risk patients of DLBCL, consolidation ASCT and rituximab maintenance therapy can't prolong the OS

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

BackgroundMesenchymal 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.MethodMSCs 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.ResultLike 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.ConclusionThese 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

Enhancement of Anti-Leukemia Immunity by Leukemia–Derived Exosomes Via Downregulation of TGF-β1 Expression

Background/Aims: Minimal residual leukemia cells (MRLs) are difficult to eradicate through traditional treatment and therefore remain to be a major threat to the long-term survival of leukemia patients. Tumor-derived exosomes (TEXs), which carry tumor associated antigens (TAA), may be a potential cell-free tumor vaccine for the specific eradication of MRLs. However, TEXs are intended to be less immunogenic due to exosomal TGF-β1. To further optimize the efficacy of TEX-based vaccines, we investigated whether exosomes from TGF-β1 silenced leukemia cells (LEXTGF-β1si) had an increased potential to induce a specific antitumor effect compared with non-modified exosomes. Methods: Exosomal TGF-β1 was downregulated via lentiviral shRNA silencing of TGF-β1 in leukemia cells. The characteristics of LEXTGF-β1si were determined via electron microscopy, western blot analysis, and flow cytometry. The antitumor effect of LEXTGF-β1si was evaluated by detecting the properties of LEXTGF-β1si-pulsed dendritic cells (DCs), CD4+ T-cell proliferation, Th1 cytokine secretion, specific CTL activity, and NK cell function. Moreover, to verify the superiority of LEXTGF-β1si immunization, LEXTGF-β1si was subcutaneously injected into DBA/2 mice: either followed by tumor challenge or tumor bearing. Results: The lentiviral shRNA silencing of TGF-β1 in parental leukemia cells successfully downregulated the TGF-β1 level in leukemia cell derived exosomes (LEX). LEXTGF-β1si was uptaken by DCs and was more potent in promoting DC function by upregulating the surface expression of costimulatory factors and MHC class II molecules, while inducing the secretion of IL-12p70 and TNF-α. Furthermore, immunization with LEXTGF-β1si facilitated CD4+ T-cell proliferation and Th1 cytokine secretion, and stimulated stronger specific cytotoxic lymphocyte (CTL) response and nature killer (NK) cell cytotoxicity more efficiently compared to non-modified LEX. In mice models, immunization with LEXTGF-β1si resulted in a more potent capability to inhibit tumor growth and to prolong survival, suggesting that LEXTGF-β1si was more effective in both protective and therapeutic antitumor tests than non-modified LEX. Conclusions: These data suggested that down-regulation of exosomal TGF-β1 effectively induced potent anti-tumor immunity. Our strategy of optimizing exosome vaccine may have promising potential for leukemia immunotherapy

Interleukin-10 Gene-Modified Dendritic Cell-Induced Type 1 Regulatory T Cells Induce Transplant-Tolerance and Impede Graft Versus Host Disease After Allogeneic Stem Cell Transplantation

Background/Aims: Tr1 cells can induce peripheral tolerance to self- and foreign antigens, and have been developed as a therapeutic tool for the induction of tolerance to transplanted tissue. We explored the feasibility of generating Tr1 cells by using IL-10 gene-modified recipient DCs (DCLV-IL-10) to stimulate donor naive CD4+ T cells. We also investigated some biological properties of Tr1 cells. Methods: DCLV-IL-10 were generated through DCs transduced with a lentivirus vector carrying the IL-10 gene, and Tr1 cells were produced by using DCLV-IL-10 to stimulate naive CD4+ T cells. The effects of Tr1 cells on T-cell proliferation and the occurrence of graft versus host disease (GVHD) following allogeneic stem-cell transplantation (allo-HSCT) were investigated. Results: The DCLV-IL-10-induced Tr1 cells co-expressed LAG-3 and CD49b. Moreover, they also expressed CD4, CD25, and IL-10, but not Foxp3, and secreted significantly higher levels of IL-10 (1,729.36 ± 185.79 pg/mL; P < 0.001) and INF-γ (1,524.48 ± 168.65 pg/mL; P < 0.01) than the control T cells upon the stimulation by allogeneic DCs. Tr1 cells markedly suppressed T-lymphocyte proliferation and the mixed lymphocytic response (MLR) in vitro. The mice used in the allo-HSCT model had longer survival times and lower clinical and pathological GVHD scores than the control mice. Conclusion: IL-10 gene-modified DC-induced Tr1 cells may be used as a potent cellular therapy for the prevention of GVHD after allo-HSCT

Dendritic Cells Pulsed with Leukemia Cell-Derived Exosomes More Efficiently Induce Antileukemic Immunities

<div><p>Dendritic cells (DCs) and tumor cell-derived exosomes have been used to develop antitumor vaccines. However, the biological properties and antileukemic effects of leukemia cell-derived exosomes (LEXs) are not well described. In this study, the biological properties and induction of antileukemic immunity of LEXs were investigated using transmission electron microscopy, western blot analysis, cytotoxicity assays, and animal studies. Similar to other tumor cells, leukemia cells release exosomes. Exosomes derived from K562 leukemia cells (LEX_K562) are membrane-bound vesicles with diameters of approximately 50–100 μm and harbor adhesion molecules (<i>e.g.</i>, intercellular adhesion molecule-1) and immunologically associated molecules (<i>e.g.</i>, heat shock protein 70). In cytotoxicity assays and animal studies, LEXs-pulsed DCs induced an antileukemic cytotoxic T-lymphocyte immune response and antileukemic immunity more effectively than did LEXs and non-pulsed DCs (<i>P</i><0.05). Therefore, LEXs may harbor antigens and immunological molecules associated with leukemia cells. As such, LEX-based vaccines may be a promising strategy for prolonging disease-free survival in patients with leukemia after chemotherapy or hematopoietic stem cell transplantation.</p></div