IL-6 trans-signaling promotes the expansion and anti-tumor activity of CAR T cells

Safe and potent anti-CD19 CAR T-cells with shRNA-IL-6 gene silencing element in patients with refractory or relapsed B-cell acute lymphoblastic leukemia

Severe cytokine release syndrome (sCRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) have limited the widespread use of chimeric antigen receptor T (CAR T)-cell therapy. We designed a novel anti-CD19 CAR (ssCART-19) with a small hairpin RNA (shRNA) element to silence the interleukin-6 (IL-6) gene, hypothesizing it could reduce sCRS and ICANS by alleviating monocyte activation and proinflammatory cytokine release. In a post hoc analysis of two clinical trials, we compared ssCART-19 with common CAR T-cells (cCART-19) in relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). Among 87 patients, 47 received ssCART-19 and 40 received cCART-19. Grade ≥3 CRS occurred in 14.89% (7/47) of the ssCART-19 group versus 37.5% (15/40) in the cCART-19 group (p = 0.036). ICANS occurred in 4.26% (2/47) of the ssCART-19 group (all grade 1) compared to 15% (2/40) of the cCART-19 group. Patients in the ssCART-19 group showed comparable rates of treatment response (calculated with rates of complete remission and incomplete hematological recovery) were 91.49% (43/47) for ssCART-19 and 85% (34/40) for cCART-19 (p = 0.999). With a median follow-up of 21.9 months, cumulative nonrelapse mortality was 10.4% for ssCART-19 and 13.6% for cCART-19 (p = 0.33). Median overall survival was 37.17 months for ssCART-19 and 32.93 months for cCART-19 (p = 0.40). Median progression-free survival was 24.17 months for ssCART-19 and 9.33 months for cCART-19 (p = 0.23). These data support the safety and efficacy of ssCART-19 for r/r B-ALL, suggesting its potential as a promising therapy.

Tuning CAR T-cell therapies for efficacy and reduced toxicity

Chimeric antigen receptor (CAR) T-cell therapies are a standard of care for certain relapsed or refractory B-cell cancers. However, many patients do not respond to CAR T-cell therapy or relapse later, short- and long-term toxicities are common, and current CAR T-cell therapies have limited efficacy for solid cancers. The gene engineering inherent in CAR T-cell manufacture offers an unprecedented opportunity to control cellular characteristics and design products that may overcome these limitations. This review summarises available methods to "tune" CAR T-cells for optimal efficacy and safety. The components of a typical CAR, and the modifications that can influence CAR T-cell function are discussed. Methods of engineering passive, inducible or autonomous control mechanisms into CAR T-cells, allowing selective limitation or enhancement of CAR T-cell activity are reviewed. The impact of manufacturing processes on CAR T-cell function are considered, including methods of limiting CAR T-cell terminal differentiation and exhaustion, and the use of specific T-cell subsets as the CAR T starting material. We discuss the use of multicistronic transgenes and multiplexed gene editing. Finally, we highlight the need for innovative clinical trial designs if we are to make the most of the opportunities offered by CAR T-cell therapies.

Harnessing cytokines to optimize chimeric antigen receptor-T cell therapy for gastric cancer: Current advances and innovative strategies

Enormous patients with gastric cancer (GC) are insensitive to chemotherapy and targeted therapy without the chance of radical surgery, so immunotherapy may supply a novel choice for them. Chimeric antigen receptor (CAR)-T cell therapy has the advantages of higher specificity, stronger lethality, and longer-lasting efficacy, and it has the potential for GC in the future. However, its application still faces numerous obstacles in terms of accuracy, efficacy, and safety. Cytokines can mediate the migration, proliferation, and survival of immune cells, regulate the duration and strength of immune responses, and are involved in the occurrence of severe side effects in CAR-T cell therapy. The expression levels of specific cytokines are associated with the genesis, invasion, metastasis, and prognosis of GC. Applications of cytokines and their receptors in CAR-T cell therapy have emerged, and various cytokines and their receptors have contributed to improving CAR-T cell anti-tumor capabilities. Large amounts of central cytokines in this therapy include chemokines, interleukins (ILs), transforming growth factor-β (TGF-β), and colony-stimulating factors (CSFs). Meanwhile, researchers have explored the combination therapy in treating GC, and several approaches applied to other malignancies can also be considered as references. Therefore, our review comprehensively outlines the biological functions and clinical significance of cytokines and summarizes current advances and innovative strategies for harnessing cytokines to optimize CAR-T cell therapy for GC.

DNA Damage-driven Inflammatory Cytokines: Reprogramming of Tumor Immune Microenvironment and Application of Oncotherapy

DNA damage occurs across tumorigenesis and tumor development. Tumor intrinsic DNA damage can not only increase the risk of mutations responsible for tumor generation but also initiate a cellular stress response to orchestrate the tumor immune microenvironment (TIME) and dominate tumor progression. Accumulating evidence documents that multiple signaling pathways, including cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) and ataxia telangiectasia-mutated protein/ataxia telangiectasia and Rad3-related protein (ATM/ATR), are activated downstream of DNA damage and they are associated with the secretion of diverse cytokines. These cytokines possess multifaced functions in the anti-tumor immune response. Thus, it is necessary to deeply interpret the complex TIME reshaped by damaged DNA and tumor-derived cytokines, critical for the development of effective tumor therapies. This manuscript comprehensively reviews the relationship between the DNA damage response and related cytokines in tumors and depicts the dual immunoregulatory roles of these cytokines. We also summarize clinical trials targeting signaling pathways and cytokines associated with DNA damage and provide future perspectives on emerging technologies.

Mitochondrial isocitrate dehydrogenase impedes CAR T cell function by restraining antioxidant metabolism and histone acetylation

The efficacy of chimeric antigen receptor (CAR) T cell therapy is hampered by relapse in hematologic malignancies and by hyporesponsiveness in solid tumors. Long-lived memory CAR T cells are critical for improving tumor clearance and long-term protection. However, during rapid ex vivo expansion or in vivo tumor eradication, metabolic shifts and inhibitory signals lead to terminal differentiation and exhaustion of CAR T cells. Through a mitochondria-related compound screening, we find that the FDA-approved isocitrate dehydrogenase 2 (IDH2) inhibitor enasidenib enhances memory CAR T cell formation and sustains anti-leukemic cytotoxicity in vivo. Mechanistically, IDH2 impedes metabolic fitness of CAR T cells by restraining glucose utilization via the pentose phosphate pathway, which alleviates oxidative stress, particularly in nutrient-restricted conditions. In addition, IDH2 limits cytosolic acetyl-CoA levels to prevent histone acetylation that promotes memory cell formation. In combination with pharmacological IDH2 inhibition, CAR T cell therapy is demonstrated to have superior efficacy in a pre-clinical model.

Emerging Therapeutic Targets and Drug Resistance Mechanisms in Immunotherapy of Hematological Malignancies

CAR-T cell therapy has revolutionized the treatment of hematological malignancies with high remission rates in the case of ALL and NHL. This therapy has some limitations such as long manufacturing periods, persistent restricted cell sources and high costs. Moreover, combination regimens increase the risk of immune-related adverse events, so the identification new therapeutic targets is important to minimize the risk of toxicities and to guide more effective approaches. Cancer cells employ several mechanisms to evade immunosurveillance, which causes resistance to immunotherapy; therefore, a very important therapeutic approach is to focus on the development of rational combinations of targeted therapies with non-overlapping toxicities. Recent progress in the development of new inhibitory clusters of differentiation (CDs), signaling pathway molecules, checkpoint inhibitors, and immunosuppressive cell subsets and factors in the tumor microenvironment (TME) has significantly improved anticancer responses. Novel strategies regarding combination immunotherapies with CAR-T cells are the most promising approach to cure cancer.

Hourglass, a rapid analysis framework for heterogeneous bioimaging data, identifies sex disparity in IL-6/STAT3-associated immune phenotypes in pancreatic cancer

Integration and mining of bioimaging data remains a challenge and lags behind the rapidly expanding digital pathology field. We introduce Hourglass, an open-access analytical framework that streamlines biology-driven visualization, interrogation, and statistical assessment of multiparametric datasets. Cognizant of tissue and clinical heterogeneity, Hourglass systematically organizes observations across spatial and global levels and within patient subgroups. Applied to an extensive bioimaging dataset, Hourglass promptly consolidated a breadth of known interleukin-6 (IL-6) functions via its downstream effector STAT3 and uncovered a so-far unknown sexual dimorphism in the IL-6/STAT3-linked intratumoral T-cell response in human pancreatic cancer. As an R package and cross-platform application, Hourglass facilitates knowledge extraction from multi-layered bioimaging datasets for users with or without computational proficiency and provides unique and widely accessible analytical means to harness insights hidden within heterogeneous tissues at the sample and patient level. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

CAR designs for solid tumors: overcoming hurdles and paving the way for effective immunotherapy

Chimeric antigen receptor T cell (CAR-T) therapy has revolutionized immunotherapy by modifying patients' immune cells genetically. By expressing CARs, these modified cells can specifically identify and eliminate tumor cells. The success of CAR-T therapy in hematological malignancies, such as leukemia and lymphoma, has been remarkable. Numerous studies have reported improved patient outcomes and increased survival rates. However, the application of CAR-T therapy in treating solid tumors faces significant challenges. Solid tumors possess complex microenvironments containing stromal cells, extracellular matrix components, and blood vessels. These factors can impede the infiltration and persistence of CAR-T cells within the tumor. Additionally, the lack of target antigens exclusively expressed on tumor cells raises concerns about off-target effects and potential toxicity. This review aims to discuss advancements achieved by CAR-T therapy in solid tumors and the clinical outcomes in the realm of solid tumors.

Administration of soluble gp130Fc disrupts M-1 macrophage polarization, dendritic cell activation, MDSC expansion and Th-17 induction during experimental cerebral malaria

Regulatory effect of IL-6 on various immune cells plays a crucial role during experimental cerebral malaria pathogenesis. IL-6 neutralization can restore distorted ratios of myeloid dendritic cells and plasmacytoid dendritic cells as well as the balance between Th-17 and T-regulatory cells. IL-6 can also influence immune cells through classical and trans IL-6 signalling pathways. As trans IL-6 signalling is reportedly involved during malaria pathogenesis, we focused on studying the effects of trans IL-6 signalling blockade on various immune cell populations and how they regulate ECM progression. Results show that administration of sgp130Fc recombinant chimera protein lowers the parasitemia, increases the survivability of Plasmodium berghei ANKA infected mice, and restores the distorted ratios of M1/M2 macrophage, mDC/pDC, and Th-17/Treg. IL-6 trans signalling blockade has been found to affect both expansion of myeloid derived suppressor cells (MDSCs) and expression of inflammatory markers on them during Plasmodium berghei ANKA infection indicating that trans IL-6 signalling might regulate various immune cells and their function during ECM. In this work for the first time, we delineate the effect of sgp130Fc administration on influencing the immunological changes within the host secondary lymphoid organ during ECM induced by Plasmodium berghei ANKA infection.

SOCS3 deletion in effector T cells confers an anti-tumorigenic role of IL-6 to the pro-tumorigenic cytokine

Interleukin (IL)-6 is abundantly expressed in the tumor microenvironment and is associated with poor patient outcomes. Here, we demonstrate that the deletion of the suppressor of cytokine signaling 3 (SOCS3) in T cells potentiates anti-tumor immune responses by conferring the anti-tumorigenic function of IL-6 in mouse and human models. In Socs3-deficient CD8+ T cells, IL-6 upregulates the expression of type I interferon (IFN)-regulated genes and enhances the anti-tumor effector function of T cells, while also modifying mitochondrial fitness to increase mitochondrial membrane potential and reactive oxygen species (ROS) levels and to promote metabolic glycolysis in the energy state. Furthermore, Socs3 deficiency reduces regulatory T cells and increases T helper 1 (Th1) cells. SOCS3 knockdown in human chimeric antigen receptor T (CAR-T) cells exhibits a strong anti-tumor response in humanized mice. Thus, genetic disruption of SOCS3 offers an avenue to improve the therapeutic efficacy of adoptive T cell therapy.

Strategies for Reducing Toxicity and Enhancing Efficacy of Chimeric Antigen Receptor T Cell Therapy in Hematological Malignancies

Chimeric antigen receptor T cell (CAR-T) therapy in hematologic malignancies has made great progress, but there are still some problems. First, T cells from tumor patients show an exhaustion phenotype; thus, the persistence and function of the CAR-Ts are poor, and achieving a satisfactory curative effect is difficult. Second, some patients initially respond well but quickly develop antigen-negative tumor recurrence. Thirdly, CAR-T treatment is not effective in some patients and is accompanied by severe side effects, such as cytokine release syndrome (CRS) and neurotoxicity. The solution to these problems is to reduce the toxicity and enhance the efficacy of CAR-T therapy. In this paper, we describe various strategies for reducing the toxicity and enhancing the efficacy of CAR-T therapy in hematological malignancies. In the first section, strategies for modifying CAR-Ts using gene-editing technologies or combining them with other anti-tumor drugs to enhance the efficacy of CAR-T therapy are introduced. The second section describes some methods in which the design and construction of CAR-Ts differ from the conventional process. The aim of these methods is to enhance the anti-tumor activity of CAR-Ts and prevent tumor recurrence. The third section describes modifying the CAR structure or installing safety switches to radically reduce CAR-T toxicity or regulating inflammatory cytokines to control the symptoms of CAR-T-associated toxicity. Together, the knowledge summarized herein will aid in designing better-suited and safer CAR-T treatment strategies.

Curtailing virus-induced inflammation in respiratory infections: emerging strategies for therapeutic interventions

Acute respiratory viral infections (ARVI) are the most common illnesses worldwide. In some instances, mild cases of ARVI progress to hyperinflammatory responses, which are damaging to pulmonary tissue and requiring intensive care. Here we summarize available information on preclinical and clinical effects of XC221GI (1-[2-(1-methyl imidazole-4-yl)-ethyl]perhydroazin-2,6-dione), an oral drug with a favorable safety profile that has been tested in animal models of influenza, respiratory syncytial virus, highly pathogenic coronavirus strains and other acute viral upper respiratory infections. XC221GI is capable of controlling IFN-gamma-driven inflammation as it is evident from the suppression of the production of soluble cytokines and chemokines, including IL-6, IL-8, CXCL10, CXCL9 and CXCL11 as well as a decrease in migration of neutrophils into the pulmonary tissue. An excellent safety profile of XC221GI, which is not metabolized by the liver, and its significant anti-inflammatory effects indicate utility of this compound in abating conversion of ambulatory cases of respiratory infections into the cases with aggravated presentation that require hospitalization. This drug is especially useful when rapid molecular assays determining viral species are impractical, or when direct antiviral drugs are not available. Moreover, XC221GI may be combined with direct antiviral drugs to enhance their therapeutic effects.

[Safety and short-term effectiveness of blinatumomab in the treatment of childhood relapsed/refractory acute lymphoblastic leukemia]

OBJECTIVES

To study the safety and short-term effectiveness of blinatumomab in the treatment of childhood relapsed/refractory acute lymphoblastic leukemia (R/R-ALL).

METHODS

Six children with R/R-ALL who received blinatumomab treatment from August 2021 to August 2022 were included as subjects, and a retrospective analysis was performed for their clinical data.

RESULTS

Among the six children, there were three boys and three girls, with a median age of 10.5 (5.0-13.0) years at the time of inclusion. Of all six children, one had refractory ALL and did not achieve remission after several times of chemotherapy, and 5 relapsed for the first time, with a median time of 30 (9-60) months from diagnosis to relapse. Minimal residual disease (MRD) before treatment was 15.50% (0.08%-78.30%). Three children achieved complete remission after treatment, among whom two had negative conversion of MRD. Five children had cytokine release syndrome (CRS), among whom 3 had grade 1 CRS and 2 had grade 2 CRS. Four children were bridged to allogeneic hematopoietic stem cell transplantation, with a median interval of 50 (40-70) days from blinatumomab treatment to transplantation. The six children were followed up for a median time of 170 days, and the results showed an overall survival rate of 41.7% (95%CI: 5.6%-76.7%) and a median survival time of 126 (95%CI: 53-199) days.

CONCLUSIONS

Blinatumomab has good short-term safety and effectiveness in the treatment of childhood R/R-ALL, and its long-term effectiveness needs to be confirmed by studies with a larger sample size.

Transcriptomic Approaches in Studies on and Applications of Chimeric Antigen Receptor T Cells

Chimeric antigen receptor T (CAR-T) cells are specifically modified T cells which bear recombinant receptors, present at the cell surface and devoted to detect selected antigens of cancer cells, and due to the presence of transmembrane and activation domains, able to eliminate the latter ones. The use of CAR-T cells in anti-cancer therapies is a relatively novel approach, providing a powerful tool in the fight against cancer and bringing new hope for patients. However, despite huge possibilities and promising results of preclinical studies and clinical efficacy, there are various drawbacks to this therapy, including toxicity, possible relapses, restrictions to specific kinds of cancers, and others. Studies desiring to overcome these problems include various modern and advanced methods. One of them is transcriptomics, a set of techniques that analyze the abundance of all RNA transcripts present in the cell at certain moment and under certain conditions. The use of this method gives a global picture of the efficiency of expression of all genes, thus revealing the physiological state and regulatory processes occurring in the investigated cells. In this review, we summarize and discuss the use of transcriptomics in studies on and applications of CAR-T cells, especially in approaches focused on improved efficacy, reduced toxicity, new target cancers (like solid tumors), monitoring the treatment efficacy, developing novel analytical methods, and others.

STAT3 regulates CD8+ T cell differentiation and functions in cancer and acute infection

In cancer, persistent antigens drive CD8+ T cell differentiation into exhausted progenitor (Texprog) and terminally exhausted (Texterm) cells. However, how the extrinsic and intrinsic regulatory mechanisms cooperate during this process still remains not well understood. Here, we found that STAT3 signaling plays essential roles in promoting intratumor Texterm cell development by enhancing their effector functions and survival, which results in better tumor control. In tumor microenvironments, STAT3 is predominantly activated by IL-10 and IL-21, but not IL-6. Besides, STAT3 also plays critical roles in the development and function of terminally differentiated effector CD8+ T cells in acute infection. Mechanistically, STAT3 transcriptionally promotes the expression of effector function-related genes, while it suppresses those expressed by the progenitor Tex subset. Moreover, STAT3 functions in collaboration with BATF and IRF4 to mediate chromatin activation at the effector gene loci. Thus, we have elucidated the roles of STAT3 signaling in terminally differentiated CD8+ T cell development, especially in cancer, which benefits the development of more effective immunotherapies against tumors.

Safety and efficacy of co-administration of CD19 and CD22 CAR-T cells in children with B-ALL relapse after CD19 CAR-T therapy

BACKGROUND

CD19-targeted chimeric antigen receptor T-cell (CAR-T) therapy has shown remarkable efficacy in treating relapsed or refractory pediatric B-lineage acute lymphoblastic leukemia (B-ALL). However, poor results are obtained when the same product is reused in patients who relapse after CAR-T. Therefore, there is a need to explore the safety and efficacy of co-administration of CD19- and CD22-targeted CAR-T as a salvage second CAR-T therapy (CART2) in B-ALL patients who relapse after their first CD19 CAR-T treatment (CART1).

METHODS

In this study, we recruited five patients who relapsed after CD19-targeted CAR-T. CD19- and CD22-CAR lentivirus-transfected T cells were cultured separately and mixed before infusion in an approximate ratio of 1:1. The total dose range of CD19 and CD22 CAR-T was 4.3 × 10⁶-1.5 × 10⁷/kg. Throughout the trial, we evaluated the patients' clinical responses, side effects, and the expansion and persistence of CAR-T cells.

RESULTS

After CART2, all five patients had minimal residual disease (MRD)-negative complete remission (CR). The 6- and 12-month overall survival (OS) rates were 100%. The median follow-up time was 26.3 months. Three of the five patients bridged to consolidated allogeneic hematopoietic stem cell transplantation (allo-HSCT) after CART2 and remained in MRD-negative CR at the cut-off time. In patient No. 3 (pt03), CAR-T cells were still detected in the peripheral blood (PB) at 347 days post-CART2. Cytokine release syndrome (CRS) only occurred with a grade of ≤ 2, and no patients experienced symptoms of neurologic toxicity during CART2.

CONCLUSIONS

Mixed infusion of CD19- and CD22-targeted CAR-T cells is a safe and effective regimen for children with B-ALL who relapse after prior CD19-targeted CAR-T therapy. Salvage CART2 provides an opportunity for bridging to transplantation and long-term survival.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2000032211. Retrospectively registered: April 23, 2020.

Disruption of CISH promotes the antitumor activity of human T cells and decreases PD-1 expression levels

Tumor cells and the immunosuppressive tumor microenvironment suppress the antitumor activity of T cells through immune checkpoints, including the PD-L1/PD-1 axis. Cytokine-inducible SH2-containing protein (CISH), a member of the suppressor of cytokine signaling (SOCS) family, inhibits JAK-STAT and T cell receptor (TCR) signaling in T and natural killer (NK) cells. However, its role in the regulation of immune checkpoints in T cells remains unclear. In this study, we ablated CISH in T cells with CRISPR-Cas9 and found that the sensitivity of T cells to TCR and cytokine stimulation was increased. In addition, chimeric antigen receptor T cells with CISH deficiency exhibited longer survival and higher cytokine secretion and antitumor activity. Notably, PD-1 expression was decreased in activated CISH-deficient T cells in vitro and in vivo. The level of FBXO38, a ubiquitination-regulating protein that reduces PD-1 expression, was elevated in activated T cells after CISH ablation. Hence, this study reveals a mechanism by which CISH promotes PD-1 expression by suppressing the expression of FBXO38 and proposes a new strategy for augmenting the therapeutic effect of CAR-T cells by inhibiting CISH.

The role of IL-6 in coronavirus, especially in COVID-19

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infects both people and animals and may cause significant respiratory problems, including lung illness: Corona Virus Disease 2019 (COVID-19). Swabs taken from the throat and nose of people who have the illness or are suspected of having it have shown this pathogenic virus. When SARS-CoV-2 infects the upper and lower respiratory tracts, it may induce moderate to severe respiratory symptoms, as well as the release of pro-inflammatory cytokines including interleukin 6 (IL-6). COVID-19-induced reduction of IL-6 in an inflammatory state may have a hitherto undiscovered therapeutic impact. Many inflammatory disorders, including viral infections, has been found to be regulated by IL-6. In individuals with COVID-19, one of the primary inflammatory agents that causes inflammatory storm is IL-6. It promotes the inflammatory response of virus infection, including the virus infection caused by SARS-CoV-2, and provides a new diagnostic and therapeutic strategy. In this review article, we highlighted the functions of IL-6 in the coronavirus, especially in COVID-19, showing that IL-6 activation plays an important function in the progression of coronavirus and is a rational therapeutic goal for inflammation aimed at coronavirus.

BET bromodomain inhibition rescues PD-1-mediated T-cell exhaustion in acute myeloid leukemia

Sustained expression of programmed cell death receptor-1 (PD-1) is correlated with the exhaustion of T cells, and blockade of the PD-1 pathway is an effective immunotherapeutic strategy for treating various cancers. However, response rates are limited, and many patients do not achieve durable responses. Thus, it is important to seek additional strategies that can improve anticancer immunity. Here, we report that the bromodomain and extraterminal domain (BET) inhibitor JQ1 inhibits PD-1 expression in Jurkat T cells, primary T cells, and T-cell exhaustion models. Furthermore, JQ1 dramatically impaired the expression of PD-1 and T-cell immunoglobulin mucin-domain-containing-3 (Tim-3) and promoted the secretion of cytokines in T cells from patients with acute myeloid leukemia (AML). In line with that, BET inhibitor-treated CD19-CAR T and CD123-CAR T cells have enhanced anti-leukemia potency and resistant to exhaustion. Mechanistically, BRD4 binds to the NFAT2 and PDCD1 (encoding PD-1) promoters, and NFAT2 binds to the PDCD1 and HAVCR2 (encoding Tim-3) promoters. JQ1-treated T cells showed downregulated NFAT2, PD-1, and Tim-3 expression. In addition, BET inhibitor suppressed programmed death-ligand 1 (PD-L1) expression and cell growth in AML cell lines and in primary AML cells. We also demonstrated that JQ1 treatment led to inhibition of leukemia progression, reduced T-cell PD-1/Tim-3 expression, and prolonged survival in MLL-AF9 AML mouse model and Nalm6 (B-cell acute lymphoblastic leukemia cell)-bearing mouse leukemia model. Taken together, BET inhibition improved anti-leukemia immunity by regulating PD-1/PD-L1 expression, and also directly suppressed AML cells, which provides novel insights on the multiple effects of BET inhibition for cancer therapy.

Comprehensive Cytokine Profiling of Patients with COVID-19 Receiving Tocilizumab Therapy

Coronavirus disease 2019 (COVID-19) is characterized by immune activation in response to viral spread, in severe cases leading to the development of cytokine storm syndrome (CSS) and increased mortality. Despite its importance in prognosis, the pathophysiological mechanisms of CSS in COVID-19 remain to be defined. Towards this goal, we analyzed cytokine profiles and their interrelation in regard to anti-cytokine treatment with tocilizumab in 98 hospitalized patients with COVID-19. We performed a multiplex measurement of 41 circulating cytokines in the plasma of patients on admission and 3-5 days after, during the follow-up. Then we analyzed the patient groups separated in two ways: according to the clusterization of their blood cytokines and based on the administration of tocilizumab therapy. Patients with and without CSS formed distinct clusters according to their cytokine concentration changes. However, the tocilizumab therapy, administered based on the standard clinical and laboratory criteria, did not fully correspond to those clusters of CSS. Furthermore, among all cytokines, IL-6, IL-1RA, IL-10, and G-CSF demonstrated the most prominent differences between patients with and without clinical endpoints, while only IL-1RA was prognostically significant in both groups of patients with and without tocilizumab therapy, decreasing in the former and increasing in the latter during the follow-up period. Thus, CSS in COVID-19, characterized by a correlated release of multiple cytokines, does not fully correspond to the standard parameters of disease severity. Analysis of the cytokine signature, including the IL-1RA level in addition to standard clinical and laboratory parameters may be useful to define the onset of a cytokine storm in COVID-19 as well as the indications for anti-cytokine therapy.

Case Report: Chimeric Antigen Receptor T Cells Induced Late Severe Cytokine Release Syndrome

Background

Severe cytokine release syndrome (sCRS) has emerged as an adverse complication in the early period of chimeric antigen receptor T cell (CART) therapy, while whether sCRS occurs in the late period remains unknown. Here, we reported two patients with late sCRS.

Case Presentation

Case 1 was a 34-year-old female with refractory Philadelphia chromosome-positive B cell acute lymphoblastic leukemia. She achieved complete remission (CR) but experienced grade III CRS and hemophagocytic lymphohistiocytosis (HLH) 41 days after CD19-targeted CART (CART19) cells and CD22-targeted CART (CART22) cells infusion. Ineffective to tocilizumab and HLH-94 protocol (dexamethasone and etoposide), she died of a cerebral hemorrhage on day 55 after CART therapy. Case 2 was a 38-year-old male with IgG kappa multiple myeloma. He received autologous BCMA-targeted CART (BCMA-CART) therapy 4 months after HLA–matched sibling (sister) donor transplantation and developed grade III CRS 163 days after CART administration, characterized by fever, hypotension, and skin lesions. Effective to methylprednisolone and tocilizumab, his clinical response persisted for over 6.0 months.

Conclusion

Severe CRS could occur in the late period after CART therapy as re-expansion of CART cells possessed the potential risk for late sCRS.

Computational Analysis of Cytokine Release Following Bispecific T-Cell Engager Therapy: Applications of a Logic-Based Model

Bispecific T-cell engaging therapies harness the immune system to elicit an effective anticancer response. Modulating the immune activation avoiding potential adverse effects such as cytokine release syndrome (CRS) is a critical aspect to realizing the full potential of this therapy. The use of suitable exogenous intervention strategies to mitigate the CRS risk without compromising the antitumoral capability of bispecific antibody treatment is crucial. To this end, computational approaches can be instrumental to systematically exploring the effects of combining bispecific antibodies with CRS intervention strategies. Here, we employ a logical model to describe the action of bispecific antibodies and the complex interplay of various immune system components and use it to perform simulation experiments to improve the understanding of the factors affecting CRS. We performed a sensitivity analysis to identify the comedications that could ameliorate CRS without impairing tumor clearance. Our results agree with publicly available experimental data suggesting anti-TNF and anti-IL6 as possible co-treatments. Furthermore, we suggest anti-IFNγ as a suitable candidate for clinical studies.

Critical care management of chimeric antigen receptor T-cell therapy recipients

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapeutic treatment concept that is changing the treatment approach to hematologic malignancies. The development of CAR T-cell therapy represents a prime example for the successful bench-to-bedside translation of advances in immunology and cellular therapy into clinical practice. The currently available CAR T-cell products have shown high response rates and long-term remissions in patients with relapsed/refractory acute lymphoblastic leukemia and relapsed/refractory lymphoma. However, CAR T-cell therapy can induce severe life-threatening toxicities such as cytokine release syndrome, neurotoxicity, or infection, which require rapid and aggressive medical treatment in the intensive care unit setting. In this review, the authors provide an overview of the state-of-the-art in the clinical management of severe life-threatening events in CAR T-cell recipients. Furthermore, key challenges that have to be overcome to maximize the safety of CAR T cells are discussed.

Mechanisms of immune effector cell-associated neurotoxicity syndrome after CAR-T treatment

Chimeric antigen receptor T-cell (CAR-T) treatment has revolutionized the landscape of cancer therapy with significant efficacy on hematologic malignancy, especially in relapsed and refractory B cell malignancies. However, unexpected serious toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) still hamper its broad application. Clinical trials using CAR-T cells targeting specific antigens on tumor cell surface have provided valuable information about the characteristics of ICANS. With unclear mechanism of ICANS after CAR-T treatment, unremitting efforts have been devoted to further exploration. Clinical findings from patients with ICANS strongly indicated existence of overactivated peripheral immune response followed by endothelial activation-induced blood-brain barrier (BBB) dysfunction, which triggers subsequent central nervous system (CNS) inflammation and neurotoxicity. Several animal models have been built but failed to fully replicate the whole spectrum of ICANS in human. Hopefully, novel and powerful technologies like single-cell analysis may help decipher the precise cellular response within CNS from a different perspective when ICANS happens. Moreover, multidisciplinary cooperation among the subjects of immunology, hematology, and neurology will facilitate better understanding about the complex immune interaction between the peripheral, protective barriers, and CNS in ICANS. This review elaborates recent findings about ICANS after CAR-T treatment from bed to bench, and discusses the potential cellular and molecular mechanisms that may promote effective management in the future. This article is categorized under: Cancer > Biomedical Engineering Immune System Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology.

A Squalene-Based Nanoemulsion for Therapeutic Delivery of Resiquimod

Agonists for toll-like receptors (TLRs) have shown promising activities against cancer. In the present study, a squalene-based nanoemulsion (NE) was loaded with resiquimod, a TLR7/8 agonist for therapeutic delivery. R848 NE was developed and characterized for long-term stability. In vitro and in vivo antitumor immunity of R848 NE were also evaluated in combination with SD-101, a CpG-containing TLR9 agonist. In vitro studies demonstrated strong long-term stability and immune responses to R848 NE. When combined with SD-101, strong antitumor activity was observed in MC38 murine colon carcinoma model with over 80% tumor growth inhibition. The combination treatment showed a 4-fold increase in systemic TNFa production and a 2.6-fold increase in Cd8a expression in tumor tissues, suggesting strong cell-mediated immune responses against the tumor. The treatment not only demonstrated a strong antitumor immunity by TLR7/8 and TLR9 activations but also induced PD-L1 upregulation in tumors, suggesting a potential therapeutic synergy with immune checkpoint inhibitors.

GD2 CAR T cells against human glioblastoma

Glioblastoma is the most malignant primary brain tumor and is still in need of effective medical treatment. We isolated patient-derived glioblastoma cells showing high GD2 antigen expression representing a potential target for CAR T strategy. Data highlighted a robust GD2 CAR antitumor potential in 2D and 3D glioblastoma models associated with a significant and CAR T-restricted increase of selected cytokines. Interestingly, immunosuppressant TGF β1, expressed in all co-cultures, did not influence antitumor activity. The orthotopic NOD/SCID models using primary glioblastoma cells reproduced human histopathological features. Considering still-conflicting data on the delivery route for targeting brain tumors, we compared intracerebral versus intravenous CAR T injections. We report that the intracerebral route significantly increased the length of survival time in a dose-dependent manner, without any side effects. Collectively, the proposed anti-GD2 CAR can counteract human glioblastoma potentially opening a new therapeutic option for a still incurable cancer.

Signaling pathways in the regulation of cytokine release syndrome in human diseases and intervention therapy

Cytokine release syndrome (CRS) embodies a mixture of clinical manifestations, including elevated circulating cytokine levels, acute systemic inflammatory symptoms and secondary organ dysfunction, which was first described in the context of acute graft-versus-host disease after allogeneic hematopoietic stem-cell transplantation and was later observed in pandemics of influenza, SARS-CoV and COVID-19, immunotherapy of tumor, after chimeric antigen receptor T (CAR-T) therapy, and in monogenic disorders and autoimmune diseases. Particularly, severe CRS is a very significant and life-threatening complication, which is clinically characterized by persistent high fever, hyperinflammation, and severe organ dysfunction. However, CRS is a double-edged sword, which may be both helpful in controlling tumors/viruses/infections and harmful to the host. Although a high incidence and high levels of cytokines are features of CRS, the detailed kinetics and specific mechanisms of CRS in human diseases and intervention therapy remain unclear. In the present review, we have summarized the most recent advances related to the clinical features and management of CRS as well as cutting-edge technologies to elucidate the mechanisms of CRS. Considering that CRS is the major adverse event in human diseases and intervention therapy, our review delineates the characteristics, kinetics, signaling pathways, and potential mechanisms of CRS, which shows its clinical relevance for achieving both favorable efficacy and low toxicity.

How Can We Engineer CAR T Cells to Overcome Resistance?

Chimeric antigen receptor (CAR) T cell therapy has achieved unrivalled success in the treatment of B cell and plasma cell malignancies, with five CAR T cell products now approved by the US Food and Drug Administration (FDA). However, CAR T cell therapies for solid tumours have not been nearly as successful, owing to several additional challenges. Here, we discuss mechanisms of tumour resistance in CAR T cell therapy and the emerging strategies that are under development to engineer CAR T cells to overcome resistance.

DAMPs released by pyroptotic cells as major contributors and therapeutic targets for CAR-T-related toxicities

CAR-T transfer, recently well-developed immunotherapy, has offered substantial benefit to more and more patients with advanced cancers. However, along with growing experience in the clinical application comes the increasing awareness of the potentially fatal adverse effects, most notably cytokine release syndrome (CRS) and neurotoxicity. Understanding the mechanisms underlying these toxicities can help to improve therapeutic outcomes. Recent findings highlight the importance of monocyte/macrophage in CAR-T-related toxicities (CARTOX) and shed light on a novel mechanism mediated by damage-associated molecular patterns (DAMPs) released from pyroptotic cells. Therefore, this review summarizes these findings and provides practical guidance to the management of CARTOX.