Comparable outcomes in patients with B-cell acute lymphoblastic leukemia receiving haploidentical hematopoietic stem cell transplantation: Pretransplant minimal residual disease-negative complete remission following chimeric antigen receptor T-cell therapy versus chemotherapy.

Introduction: Chimeric antigen receptor (CAR) T-cell (CAR-T) therapy followed by haploidentical hematopoietic stem cell transplantation (haplo-HSCT) markedly improves the long-term survival of patients with refractory/relapsed (R/R) B-cell acute lymphoblastic leukemia (B-ALL). Methods: We performed a parallel comparison of transplant outcomes in 168 B-ALL patients undergoing haplo-HSCT after achieving minimal residual disease (MRD)-negative complete remission (CR) from CAR-T therapy (n = 28) or chemotherapy (n = 140) between January 2016 and August 2021. We further divided the chemotherapy group into the first CR group (chemo+CR1, n = 118) and a second or more CR group (chemo+≥CR2, n = 22). Results: With a median follow-up period of 31.0 months, the 2-year overall survival (OS), leukemia-free survival (LFS), non-relapse mortality (NRM), and relapse rates in the CAR-T and chemotherapy groups did not differ significantly (OS, 87.9% vs. 71.5 %; LFS, 72.0% vs. 66.8%; NRM, 3.9% vs. 13.7%; relapse, 24.1% vs. 19.4%). Multivariate analysis confirmed that ≥CR2 at transplantation following chemotherapy was an independent risk factor associated with poor OS (hazard ratio (HR) 4.22 [95% CI, 1.34-13.293], p = 0.014) and LFS (HR 2.57 [95% CI, 1.041-6.343], p = 0.041). The probabilities of OS and LFS at 2 years in the CAR-T group were comparable to those in the chemo+CR1 group but significantly higher than those in the chemo+≥CR2 group (OS, 87.9% vs. 37.8%, p = 0.007; LFS, 72.0% vs. 41.7%, p = 0.043). No significant differences in the incidences of NRM were noted among the three groups. Conclusions: Our results demonstrated that patients with R/R B-ALL receiving haplo-HSCT after CAR-T therapy achieved comparable outcomes to patients transplanted post-chemotherapy-based MRD-negative CR1, without increased risk of transplant-related mortality and toxicity.

Combination of CRISPR/Cas9 System and CAR-T Cell Therapy: A New Era for Refractory and Relapsed Hematological Malignancies.

Chimeric antigen receptor T (CAR-T) cell therapy is the novel treatment strategy for hematological malignancies such as acute lymphoblastic leukemia (ALL), lymphoma and multiple myeloma. However, treatment-related toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) have become significant hurdles to CAR-T treatment. Multiple strategies were established to alter the CAR structure on the genomic level to improve efficacy and reduce toxicities. Recently, the innovative gene-editing technology-clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease9 (Cas9) system, which particularly exhibits preponderance in knock-in and knockout at specific sites, is widely utilized to manufacture CAR-T products. The application of CRISPR/Cas9 to CAR-T cell therapy has shown promising clinical results with minimal toxicity. In this review, we summarized the past achievements of CRISPR/Cas9 in CAR-T therapy and focused on the potential CAR-T targets.

Current advances in chimeric antigen receptor T-cell therapy for refractory/relapsed multiple myeloma.

Multiple myeloma (MM), considered an incurable hematological malignancy, is characterized by its clonal evolution of malignant plasma cells. Although the application of autologous stem cell transplantation (ASCT) and the introduction of novel agents such as immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs) have doubled the median overall survival to eight years, relapsed and refractory diseases are still frequent events in the course of MM. To achieve a durable and deep remission, immunotherapy modalities have been developed for relapsed/refractory multiple myeloma (RRMM). Among these approaches, chimeric antigen receptor (CAR) T-cell therapy is the most promising star, based on the results of previous success in B-cell neoplasms. In this immunotherapy, autologous T cells are engineered to express an artificial receptor which targets a tumor-associated antigen and initiates the T-cell killing procedure. Tisagenlecleucel and Axicabtagene, targeting the CD19 antigen, are the two pacesetters of CAR T-cell products. They were approved by the US Food and Drug Administration (FDA) in 2017 for the treatment of acute lymphocytic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). Their development enabled unparalleled efficacy in combating hematopoietic neoplasms. In this review article, we summarize six promising candidate antigens in MM that can be targeted by CARs and discuss some noteworthy studies of the safety profile of current CAR T-cell therapy.

Weathering the storm: COVID-19 infection in patients with hematological malignancies.

The coronavirus disease 2019 (COVID-19) is an emerging infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Within a matter of months, this highly contagious novel virus has led to a global outbreak and is still spreading rapidly across continents. In patients with COVID-19, underlying chronic diseases and comorbidities are associated with dismal treatment outcomes. Owing to their immunosuppressive status, patients with hematological malignancies (HMs) are at an increased risk of infection and have a worse prognosis than patients without HMs. Accordingly, intensive attention should be paid to this cohort. In this review, we summarize and analyze specific clinical manifestations for patients with coexisting COVID-19 and HMs. Furthermore, we briefly describe customized management strategies and interventions for this susceptible cohort. This review is intended to guide clinical practice.

Rapamycin interacts synergistically with idarubicin to induce T-leukemia cell apoptosis in vitro and in a mesenchymal stem cell simulated drug-resistant microenvironment via Akt/mammalian target of rapamycin and extracellular signal-related kinase signaling pathways.

T-cell acute lymphoblastic leukemias (T-ALLs) are clonal lymphoid malignancies with a poor prognosis, and still a lack of effective treatment. Here we examined the interactions between the mammalian target of rapamycin (mTOR) inhibitor rapamycin and idarubicin (IDA) in a series of human T-ALL cell lines Molt-4, Jurkat, CCRF-CEM and CEM/C1. Co-exposure of cells to rapamycin and IDA synergistically induced T-ALL cell growth inhibition and apoptosis mediated by caspase activation via the intrinsic mitochondrial pathway and extrinsic pathway. Combined treatment with rapamycin and IDA down-regulated Bcl-2 and Mcl-1, and inhibited the activation of phosphoinositide 3-kinase (PI3K)/mTOR and extracellular signal-related kinase (ERK). They also played synergistic pro-apoptotic roles in the drug-resistant microenvironment simulated by mesenchymal stem cells (MSCs) as a feeder layer. In addition, MSCs protected T-ALL cells from IDA cytotoxicity by up-regulating ERK phosphorylation, while rapamycin efficiently reversed this protective effect. Taken together, we confirm the synergistic antitumor effects of rapamycin and IDA, and provide an insight into the potential future clinical applications of combined rapamycin-IDA regimens for treating T-cell malignancies.

Relapsing hematologic malignancies after haploidentical hematopoietic stem cell transplantation.

Haploidentical hematopoietic stem cell transplantation (HSCT) is a potentially curative therapeutic regimen that could increase donor availability to nearly 100%. Rapid advances in medical technology and the application of novel drugs mean that most haploidentical HSCT-associated complications can now be prevented or remarkably well controlled, even cured. However, relapsing hematologic malignancy remains a major cause of death in haploidentical HSCT recipients. Haploidentical HSCT should theoretically trigger a more potent graft-versus-tumor effect compared with human leukocyte antigen-identical transplantation, due mainly to the major histocompatibility complex and minor histocompatibility anitigen disparities on donors' immune cells and recipients' tumor cells. The underlying mechanisms of such relapsing hematologic malignancies remain elusive. In this review, we suggest correlating factors and potential mechanisms and examine feasible therapeutic and preventive strategies for relapsing hematologic malignancies after haploidentical HSCT.

Donor-derived solid malignancies after hematopoietic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation is considered to be a potentially therapeutic strategy for various hematopoietic benign diseases and malignancies. The growing number of reports on long-term survivors after hematopoietic stem cell transplantation reveals the major merits of this strategy. However, such cohorts remain at high risk of potential late complications, including the development of secondary solid malignancies. An increasing number of cases of secondary malignancies originated from recipients, donors, or unknown sources has been reported. In this review, we focus on latest clinical evidence of donor-derived solid malignancies after allogeneic hematopoietic stem cell transplantation, postulate related potential mechanisms, and further address novel indications as well as feasible therapeutic and preventive perspectives.

[Anti-cD20scFv/CD80/CD28/zeta specific T lymphocytes eradicate primary chronic lymphocytic leukemia cells in vitro].

OBJECTIVE: To construct anti-CD20scFv/CD80/CD28/zeta recombinant gene modified T cells, test its effectiveness of eradicating CD20 positive primary chronic lymphocytic leukemia (CLL) cells and provide a promising tool for tumor adoptive immunotherapy. METHODS: The recombinant vectors were transduced into PA 317 cells and high titer retroviruses were obtained to infect human peripheral blood T lymphocytes. Resistant T cells were obtained by G418 selection for one week. Then transduced T lymphocytes and primary CLL cells were co-cultured. The status of primary chronic lymphocytic leukemia cells were observed by microscope. The level of IL-2 and IFN-gamma in the culture medium were measured. RESULTS: Primary T cells expressing anti-CD20scFv/IgGFc/CD80/CD28/zeta could be constructed successfully. These T cells were able to lyse CD20+ targets and secrete high levels of IL-2 (1301.00 pg/ml) and IFN-gamma (602.18 pg/ml) in vitro. CONCLUSION: (1) Recombinant gene modified T cells can be constructed successfully. (2) Recombinant gene modified T cells can specially kill CD20 positive primary CLL cells in vitro.

[Construction of recombinant retroviruses expressing anti-CD20 scFv/CD80 /CD28/zeta gene and expression in Jurkat cell line].

AIM: To construct recombinant retroviruses expressing anti-CD20 scFv/CD80/CD28/zeta gene and detect its expression in Jurkat cells. METHOD: CD28-zetacDNA were amplified from plasmids pBULLET and inserted into pLNCX vector that contained anti-CD20 scFv/CD80 gene. The recombinant plasmids were transfected into PA 317 cells. Retroviruses were harvested from culture medium of PA 317 cells. Then NIH 3T3 were transfected with retroviruses. Objective gene expression was determined by PCR and FACS. Jurkat cells were transfected with high titer of retroviruses and resistant clones were obtained by G418 selection. Objective mRNA was determined by RT- PCR. RESULTS: The recombinant eukaryotic vector was constructed successfully by PCR and enzyme digestion analysis and objective gene was amplified from NIH 3T3 cells transfected with retroviruses by PCR; FACS showed that objective protein could be expressed in NIH 3T3 cells. Objective gene was amplified from Jurkat cells transfected with retroviruses by RT-PCR. CONCLUSION: Recombinant retrovirus expressing anti-CD20 scFv/CD80/CD28/zeta gene was successfully constructed and objective protein could be expressed in Jurkat cells.

[Construction of anti-cD20scFv/CD80/CD28/zeta recombinant gene modified T cell and research on its targeting cytotoxicity].

OBJECTIVE: To construct anti-CD20scFv/CD80/CD28/zeta recombinant gene modified T cells, test its effectiveness of eradicating CD20+ lymphoma cells and provide a probably new approach to tumor adoptive immunotherapy. METHODS: CD28-zeta cDNA were amplified from vector pBULLET and inserted into pLNCX vector that contained anti-CD20scFv/CD80 gene. The recombinant vectors were transduced into PA317 cells and high titer retroviruses were obtained to infect human peripheral blood T lymphocytes. Resistant T cells were obtained by G418 selection at one week. Then transduced T lymphocytes and lymphoma cell lines Daudi Raji were cocultured. The cytotoxicity and cytokine production of transduced T cells were determined by non-radio-activation cytotoxicity assay and ELISA respectively. RESULTS: The recombinant eukaryotic vector was constructed successfully as proved by enzyme digestion analysis and sequencing. These T cells were able to lyse CD20+ target cells and secrete high levels of IL-2 and IFN-gamma in vitro. CONCLUSION: Recombinant gene modified T cells can be constructed successfully. It can specially kill CD20 positive lymphoma cells in vitro.