The cardiotoxic effects of CAR-T cell therapy: An updated systematic review and meta-analysis.

BACKGROUND: Chimeric antigen receptor T-cell (CAR-T) therapy has shown promise in treating hematologic malignancies, yet its potential cardiotoxic effects require thorough investigation. OBJECTIVES: We aim to conduct a systematic review and meta-analysis to examine the cardiotoxic effects of CAR-T therapy in adults with hematologic malignancies. METHODS: We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials for studies reporting cardiovascular outcomes, such as arrhythmias, heart failure, and reduced left ventricle ejection fraction (LVEF). RESULTS: Our analysis of 20 studies involving 4789 patients revealed a 19.68% incidence rate of cardiovascular events, with arrhythmias (7.70%), heart failure (5.73%), and reduced LVEF (3.86%) being the most prevalent. Troponin elevation was observed in 23.61% of patients, while NT-Pro-BNP elevation was observed in 9.4. Subgroup analysis showed higher risks in patients with pre-existing conditions, such as atrial arrhythmia (OR 3.12; p < .001), hypertension (OR 1.85; p = .002), previous heart failure (OR 3.38; p = .003), and coronary artery disease (OR 2.80; p = .003). CONCLUSION: Vigilant cardiovascular monitoring is crucial for patients undergoing CAR-T therapy to enhance safety and treatment efficacy.Novelty Statements.

CD19 CAR T cells for B cell malignancies: a systematic review and meta-analysis focused on clinical impacts of CAR structural domains, manufacturing conditions, cellular product, doses, patient's age, and tumor types.

CD19-targeted chimeric antigen receptors (CAR) T cells are one of the most remarkable cellular therapies for managing B cell malignancies. However, long-term disease-free survival is still a challenge to overcome. Here, we evaluated the influence of different hinge, transmembrane (TM), and costimulatory CAR domains, as well as manufacturing conditions, cellular product type, doses, patient's age, and tumor types on the clinical outcomes of patients with B cell cancers treated with CD19 CAR T cells. The primary outcome was defined as the best complete response (BCR), and the secondary outcomes were the best objective response (BOR) and 12-month overall survival (OS). The covariates considered were the type of hinge, TM, and costimulatory domains in the CAR, CAR T cell manufacturing conditions, cell population transduced with the CAR, the number of CAR T cell infusions, amount of CAR T cells injected/Kg, CD19 CAR type (name), tumor type, and age. Fifty-six studies (3493 patients) were included in the systematic review and 46 (3421 patients) in the meta-analysis. The overall BCR rate was 56%, with 60% OS and 75% BOR. Younger patients displayed remarkably higher BCR prevalence without differences in OS. The presence of CD28 in the CAR's hinge, TM, and costimulatory domains improved all outcomes evaluated. Doses from one to 4.9 million cells/kg resulted in better clinical outcomes. Our data also suggest that regardless of whether patients have had high objective responses, they might have survival benefits from CD19 CAR T therapy. This meta-analysis is a critical hypothesis-generating instrument, capturing effects in the CD19 CAR T cells literature lacking randomized clinical trials and large observational studies.

Sicca syndrome/Sjögren's disease associated with cancer immunotherapy: a narrative review on clinical presentation, biomarkers, and management.

INTRODUCTION: Almost one-quarter of immune checkpoint inhibitor (ICI) recipients experience sicca syndrome, while Sjögren's disease (SjD) is estimated at 0.3-2.5%, possibly underreported. AREAS COVERED: This narrative review (Medline/Embase until January/31/2024) addresses the pathophysiology, incidence, demographic/clinical features, biomarkers, labial salivary gland biopsy (LSGB), fulfillment of the idiopathic SjD (iSjD) classificatory criteria, differential diagnosis, and management of sicca syndrome/SjD associated with ICIs. EXPERT OPINION: SjD associated with ICIs is underdiagnosed, since studies that performed the mandatory SjD investigation identified that 40-60% of patients with sicca syndrome associated with ICIs meet the iSjD classificatory criteria. LSGB played a fundamental role in recognizing these cases, as most of them had negative anti-Ro/SS-A antibody. Despite the finding of focal lymphocytic sialoadenitis in LSGB samples mimicking iSjD, immunohistochemical analysis provided novel evidence of a distinct pattern for sicca syndrome/SjD associated with ICIs compared to iSjD. The former has scarcity of B lymphocytes, which are a hallmark of iSjD. Additionally, patients with sicca syndrome/SjD associated with ICIs have demographical/clinical/serological and treatment response dissimilarities compared to iSjD. Dryness symptoms are more acute in the former than in iSjD, with predominance of xerostomia over xerophthalmia, and partial/complete response to glucocorticoids. Dryness symptoms in ICI-treated patients warrant prompt SjD investigation.

In silico and in vivo analysis reveal impact of c-Myc tag in FMC63 scFv-CD19 protein interface and CAR-T cell efficacy.

Anti-CD19 CAR-T cell therapy represents a breakthrough in the treatment of B-cell malignancies, and it is expected that this therapy modality will soon cover a range of solid tumors as well. Therefore, a universal cheap and sensitive method to detect CAR expression is of foremost importance. One possibility is the use of epitope tags such as c-Myc, HA or FLAG tags attached to the CAR extracellular domain, however, it is important to determine whether these tags can influence binding of the CAR with its target molecule. Here, we conducted in-silico structural modelling of an FMC63-based anti-CD19 single-chain variable fragment (scFv) with and without a c-Myc peptide tag added to the N-terminus portion and performed molecular dynamics simulation of the scFv with the CD19 target. We show that the c-Myc tag presence in the N-terminus portion does not affect the scFv's structural equilibrium and grants more stability to the scFv. However, intermolecular interaction potential (IIP) analysis reveals that the tag can approximate the complementarity-determining regions (CDRs) present in the scFv and cause steric impediment, potentially disturbing interaction with the CD19 protein. We then tested this possibility with CAR-T cells generated from human donors in a Nalm-6 leukemia model, showing that CAR-T cells with the c-Myc tag have overall worse antitumor activity, which was also observed when the tag was added to the C-terminus position. Ultimately, our results suggest that tag addition is an important aspect of CAR design and can influence CAR-T cell function, therefore its use should be carefully considered.

CAR T-cell therapy and the onco-nephrologist.

Cell therapy, specifically the revolutionary chimeric antigen receptor (CAR) T-cell therapy, has transformed the landscape of oncology, making substantial strides in practical treatment approaches. Today, established guidelines for diseases such as lymphomas, myelomas, and leukemias actively advocate the utilization of these once-unconventional therapies. The practical impact of these therapies is underscored by their unparalleled efficacy, reshaping the way we approach and implement treatments in the realm of oncology. However, CAR T-cell therapy, with its performance in anti-tumor aggression through cellular action and inflammatory response, also comes with various adverse events, one of which is kidney injury. Therefore, the management of these side effects is extremely important. The integration of knowledge between oncologists and specialized nephrologists has led to the emergence of a new sub-area of expertise for onco-nephrologists specializing in managing kidney complications from immune effector therapies.

CAR-T cell therapy: a game-changer in cancer treatment and beyond.

In recent years, cancer has become one of the primary causes of mortality, approximately 10 million deaths worldwide each year. The most advanced, chimeric antigen receptor (CAR) T cell immunotherapy has turned out as a promising treatment for cancer. CAR-T cell therapy involves the genetic modification of T cells obtained from the patient's blood, and infusion back to the patients. CAR-T cell immunotherapy has led to a significant improvement in the remission rates of hematological cancers. CAR-T cell therapy presently limited to hematological cancers, there are ongoing efforts to develop additional CAR constructs such as bispecific CAR, tandem CAR, inhibitory CAR, combined antigens, CRISPR gene-editing, and nanoparticle delivery. With these advancements, CAR-T cell therapy holds promise concerning potential to improve upon traditional cancer treatments such as chemotherapy and radiation while reducing associated toxicities. This review covers recent advances and advantages of CAR-T cell immunotherapy.

Autologous, allogeneic hematopoietic cell transplantation and CAR-T/NK therapy: what is their real importance in PTCL?

Peripheral T cell lymphoma (PTCL) is a rare and aggressive type of non-Hodgkin's lymphoma that affects mature T cells. This type of cancer is characterized by the abnormal growth of T cells, which can accumulate in the lymph nodes, spleen, bone marrow, and other organs, leading to a variety of symptoms. PTCLs are often difficult to diagnose and treat, and they have a poorer prognosis than other types of lymphoma. However, recent advancements in treatment options, such as targeted therapies have shown promise in improving outcomes for patients with PTCL. Here, we discuss the use of autologous and allogeneic hematopoietic cell transplantation (HCT) as a treatment strategy for patients with PTCL, as well as the recent treatment approaches based on advanced cellular therapy. The current evidence for the use of HCT in PTCL is mainly derived from registry data, retrospective studies, and expert opinion, as randomized trials are limited due to the low incidence and histological heterogeneity of PTCL subtypes.

Recent advances in CAR T-cell therapy for lymphoma in China.

Lymphoma is a hematologic malignancy which mainly consists of Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Although systemic chemotherapy, radiotherapy, and other advanced therapeutics, including rituximab or immune checkpoint inhibitors, have improved the prognosis in recent decades, there are still a number of patients with relapsed or refractory (R/R) lymphoma with a poor prognosis. Chimeric antigen receptor (CAR) T-cell therapy has provided a curative option for patients with relapsed or refractory lymphoma. Numerous clinical trials have been conducted worldwide and presented inspiring results that give insight into this breakthrough therapy. The development of cancer cell therapy in China has been rapid in the past years and dominates the field with the USA. This review aims to summarize the published results of CAR T-cell therapy alone or in combination with other therapies in mainland China, both in R/R NHL and R/R HL.

CAR-T cell therapy for multiple myeloma: a practical toolkit for treatment in Brazil.

INTRODUCTION: Chimeric antigen receptor T (CAR-T) cell therapy is an emerging treatment option for relapsed/refractory multiple myeloma (RRMM) that is a multi-step process involving various stakeholders. Appropriate education on the practical logistics is therefore paramount to ensure treatment success. METHODS: A group of key opinion leaders met to explore the key elements of setting up and running a CAR-T center in Brazil. For each step in the CAR-T cell therapy process, the experts agreed on basic requirements, gave their key recommendations from practical experience, and considered any remaining unanswered questions. RESULTS: This paper presents best-practice recommendations and advice on how to overcome common challenges for each step in the CAR-T cell therapy process, with a focus on the current situation in Brazil. Key themes throughout the process are collaboration within the multidisciplinary team and with the referring physician, along with communication and education for patients and their caregivers. CONCLUSION: We believe that the expert insights presented in this paper, in particular on optimal patient selection and timing of CAR-T cell therapy, will deepen understanding of the CAR-T process and aid implementation of this novel therapy for patients with RRMM in Brazil.

CAR-T cell therapy for multiple myeloma: a practical toolkit for treatment in Brazil

ABSTRACT Introduction Chimeric antigen receptor T (CAR-T) cell therapy is an emerging treatment option for relapsed/refractory multiple myeloma (RRMM) that is a multi-step process involving various stakeholders. Appropriate education on the practical logistics is therefore paramount to ensure treatment success. Methods A group of key opinion leaders met to explore the key elements of setting up and running a CAR-T center in Brazil. For each step in the CAR-T cell therapy process, the experts agreed on basic requirements, gave their key recommendations from practical experience, and considered any remaining unanswered questions. Results This paper presents best-practice recommendations and advice on how to overcome common challenges for each step in the CAR-T cell therapy process, with a focus on the current situation in Brazil. Key themes throughout the process are collaboration within the multidisciplinary team and with the referring physician, along with communication and education for patients and their caregivers. Conclusion We believe that the expert insights presented in this paper, in particular on optimal patient selection and timing of CAR-T cell therapy, will deepen understanding of the CAR-T process and aid implementation of this novel therapy for patients with RRMM in Brazil.

Monitoreo de las insuficiencias orgánicas en pacientes graves con hemopatías malignas por el uso de las células CAR-T / Monitoring of organ failures in critically ill patients with blood malignancies by the use of CAR - T cell

Introducción: La inmunoterapia con células T modificadas con receptor quimérico antígeno específico es un tratamiento prometedor para hemopatías malignas. Sin embargo, la activación dirigida de la respuesta inmunitaria desata en ciertos casos complicaciones específicas graves y mortales. Objetivos: Describir el monitoreo de las complicaciones por el uso de las células T con receptor antígeno quimérico en pacientes graves con hemopatías malignas. Métodos: Se realizó una investigación bibliográfico documental acerca del tema. Se consultaron las bases de datos de SciELO y PubMed de los últimos cinco años. Conclusiones: Se describieron las complicaciones derivadas de la terapia con células inmunoefectoras, que aumentan el desarrollo de insuficiencias orgánicas, a través del síndrome de liberación de citoquinas y el síndrome de toxicidad neurológica. El tratamiento se basó en establecer medidas de monitorización y soporte, tratamiento con anticonvulsivantes, corticosteroides e ingreso en los servicios de medicina intensiva de forma precoz. Se disminuyó el riesgo en la aparición de complicaciones y muerte con un adecuado monitoreo de las insuficiencias orgánicas derivadas de la inmunoterapia de células T con receptor antígeno quimérico.

Introduction: Immunotherapy with T-cells modified with antigen-specific chimeric receptor is a promising treatment for malignant hemopathies. However, the targeted activation of the immune response in certain cases unleashes specific severe and fatal complications. Objectives: To describe the monitoring of complications from the use of CAR T-cells in critically ill patients with blood malignancies. Methods: A bibliographical-documentary research on the subject was carried out. The SciELO and Pubmed databases of the last five years were consulted. Conclusions: Complications derived from the therapy with immunoeffector cells are described, which increase the development of organ failures, through the cytokine release syndrome and the neurological toxicity syndrome. Treatment is based on monitoring and support measures, treatment with anticonvulsants, corticosteroids, and early admission to intensive care. With adequate monitoring of organ failure derived from chimeric antigen receptor T-cell immunotherapy, a decreased risk of complications and death in these patients was carried out.

Modeling Patient-Specific CAR-T Cell Dynamics: Multiphasic Kinetics via Phenotypic Differentiation.

Chimeric Antigen Receptor (CAR)-T cell immunotherapy revolutionized cancer treatment and consists of the genetic modification of T lymphocytes with a CAR gene, aiming to increase their ability to recognize and kill antigen-specific tumor cells. The dynamics of CAR-T cell responses in patients present multiphasic kinetics with distribution, expansion, contraction, and persistence phases. The characteristics and duration of each phase depend on the tumor type, the infused product, and patient-specific characteristics. We present a mathematical model that describes the multiphasic CAR-T cell dynamics resulting from the interplay between CAR-T and tumor cells, considering patient and product heterogeneities. The CAR-T cell population is divided into functional (distributed and effector), memory, and exhausted CAR-T cell phenotypes. The model is able to describe the diversity of CAR-T cell dynamical behaviors in different patients and hematological cancers as well as their therapy outcomes. Our results indicate that the joint assessment of the area under the concentration-time curve in the first 28 days and the corresponding fraction of non-exhausted CAR-T cells may be considered a potential marker to classify therapy responses. Overall, the analysis of different CAR-T cell phenotypes can be a key aspect for a better understanding of the whole CAR-T cell dynamics.

CAR-T cell therapy for patients with hematological malignancies. A systematic review.

Hematological malignancies represent defying clinical conditions, with high levels of morbidity and mortality, particularly considering patients who manifest multiple refractory diseases. Recently, chimeric antigen receptor (CAR)-T cell therapy has emerged as a potential treatment option for relapsed/refractory B cell malignancies, which have motivated the Food and Drug Administration approval of a series of products based on this technique. The objective of this systematic review was to assess the efficacy and safety of CAR-T cell therapy for patients with hematological malignancies. A comprehensive literature search was conducted in the electronic databases (CENTRAL, Embase, LILACS, and MEDLINE), clinical trials register platforms (Clinicaltrials.gov and WHO-ICTRP), and grey literature (OpenGrey). The Cochrane Handbook for Reviews of Interventions was used for developing the review and the PRISMA Statement for manuscript reporting. The protocol was prospectively published in PROSPERO database (CRD42020181047). After the selection process, seven RCTs were included, three of which with available outcome results. The available results are from studies assessing axicabtagene, lisocabtagene, and tisagenlecleucel for patients with B cell lymphoma, and the certainty of evidence ranged from very low to low for survival and progression-related outcome and for safety outcomes. Additionally, four randomized controlled trials comparing CAR-T cell therapy to the standard treatment for various types of relapsed/refractory B cell non-Hodgkin lymphomas and multiple myeloma included in this systematic review still did not have available outcome data. The results of this review may be used to guide clinical practice but evidence concerning the safety and efficacy of CAR-T Cell therapy for hematological malignancies is still immature to recommend its application outside of clinical trials or compassionate use context for advanced and terminal cases. It is expected the results of the referred comparative studies will provide further elements to subsidize the broader application of this immunotherapy.

Terapia com células CAR-T: reprogramação celular para o combate de neoplasias malignas / CAR-T cell therapy: cell reprogramming to combat malignant neoplasms

As células CAR-T são linfócitos geneticamente modificados para reconhecerem um espectro amplo de antígenos de superfície celulares. Além disso, atacam células tumorais malignas, que expressam esses antígenos, por meio da ativação da coestimulação citoplasmática, secreção de citocinas, citólise de células tumorais e proliferação de células T. O objetivo desse estudo é abordar a imunoterapia com células CAR-T, a fim de explicar seu conceito, processo de fabricação e papel no tratamento de neoplasias hematológicas e tumores sólidos. Foi realizada uma revisão através do portal PubMed, utilizando como descritores: "car-t cell therapy" e "neoplasms", determinados com base nos "Descritores em Ciências da Saúde". Foram obtidos, inicialmente, 10 artigos, os quais foram lidos integralmente para a confecção dessa revisão. Além disso, foram adicionados 3 ensaios clínicos atualizados sobre o tema. Na terapia com células CAR-T, as células T são coletadas do paciente, geneticamente modificadas para incluir receptores de antígeno específicos e, posteriormente, expandidas em laboratórios e transfundidas de volta para o paciente. Assim, esses receptores podem reconhecer células tumorais que expressam um antígeno associado a um tumor. A terapia com células CAR-T é mais conhecida por seu papel no tratamento de malignidades hematológicas de células B, sendo a proteína CD19 o alvo antigênico mais bem estudado até o momento. Entretanto, estudos estão sendo feitos para verificar a eficácia desse tratamento, também, em tumores sólidos. Portanto, apesar de inicialmente ser indicada apenas para um grupo seleto de pessoas, essa terapia tem demonstrado grande potencial para atuar em um espectro maior de pacientes.

The CAR-T cells are lymphocytes genetically modified to recognize a broader spectrum of cell surface antigens. In addition, they attack malignant tumor cells, which express these antigens, by activating cytoplasmic co-stimulation, cytokine secretion, tumor cell cytolysis and T cell proliferation. The aim of this study is to address immunotherapy with CAR-T cells, in order to explain its concept, manufacturing process and role in the treatment of hematological neoplasms and solid tumors. This is a literature review conducted through the PubMed portal, that uses the terms "car-t cell therapy" and "neoplasms" as descriptors, determined based on the DeCS (Descritores em Ciências da Saúde). To prepare this review, initially 10 articles were found and read in full. In addition, 3 updated clinical trials on the subject were added. For CAR-T cell therapy, T cells are collected from the patient, genetically modified to include specific antigen receptors, and later expanded in laboratories and transfused back to the patient. Thus, these receptors can recognize tumor cells that express a tumor-associated antigen. CAR-T cell therapy is best known for its role in the treatment of B cell hematological malignancies, with the CD19 protein being the most studied antigenic target to date. However, studies are being conducted to verify the effectiveness of this treatment, also, in solid tumors. Therefore, despite being formulated only for a selected group of patients, this therapy has great potential to act on a broader spectrum of patients.

Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular Consensus on genetically modified cells. V: Manufacture and quality control.

Chimeric antigen receptor T cells (CAR-T), especially against CD19 marker, present in lymphomas and acute B leukemia, enabled a revolution in the treatment of hematologic neoplastic diseases. The manufacture of CAR-T cells requires the adoption of GMP-compatible methods and it demands the collection of mononuclear cells from the patient (or from the donor), generally through the apheresis procedure, T cell selection, activation, transduction and expansion ex vivo, and finally storage, usually cryopreserved, until the moment of their use. An important aspect is the quality control testing of the final product, for example, the characterization of its identity and purity, tests to detect any contamination by microorganisms (bacteria, fungi, and mycoplasma) and its potency. The product thawing and intravenous infusion do not differ much from what is established for the hematopoietic progenitor cell product. After infusion, it is important to check for the presence and concentration of CAR-T cells in the patient's peripheral blood, as well as to monitor their clinical impact, for instance, the occurrence of short-term, such as cytokine release syndrome and neurological complications, and long-term complications, which require patient follow-up for many years.

Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular Consensus on genetically modified cells. VI: Accreditation process.

The adherence to accreditation programs proves the institutions' voluntary effort to pursue the quality and safety of their products and services by meeting internationally accepted standards audited by experts in the field, external to the service. Meeting such standards often exceeds domestic legal requirements. However, service providers are not released from complying with the legal requirements, both local and international, pertinent to the field. Accreditation programs use the precepts of the quality management system to validate and standardize processes, monitor results through quality control, proficiency testing, and indicators, and perform risk management. For cellular therapy services, the assessing agencies available in our field are the AABB/ABHH (American Association of Blood Banks/Brazilian Association of Hematology, Hemotherapy and Cellular Therapy) and FACT-JACIE (Foundation for the Accreditation of Cellular Therapy-Joint Accreditation Committee, ISCT/EBMT). Both agencies require that the accredited organization meets all the standards defined in each program. Applying services also have to establish and comply with a quality management standard that demonstrates procedural interrelationship to ensure product and service quality. This paper aims to concisely outline the essential features of those two accreditation programs, along with a brief overview of the accreditation process under each of them.

Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular Consensus on genetically modified cells. Special article: compassionate use and clinical trial on CAR-T cells.

There are only two ways for a patient to gain access to treatment with an experimental product, such as CAR-T cells: participate in a clinical trial or receive a product in a compassionate basis. In the first case, the main beneficiary is society itself, which may in turn obtain a new treatment paradigm for a specific disease. In the second case, the use of a medicinal product has the objective of care in benefit of patients in grave clinical condition, for which no approved medicinal products exist, or for which all the possibilities for benefit from standard therapies have been exhausted. The CAR-T cell therapy may be included in one or the other types of access. The compassionate use is not a specific type of clinical research and should therefore not have its use appreciated by a research ethics committee, but rather by the medical ethics committee at the institution where the treatment will take place and by the regulatory agency.

Are chimeric antigen receptor T cells (CAR-T cells) the future in immunotherapy for autoimmune diseases?

OBJECTIVE: CAR-T cell therapy has revolutionized the treatment of oncological diseases, and potential uses in autoimmune diseases have recently been described. The review aims to integrate the available data on treatment with CAR-T cells, emphasizing autoimmune diseases, to determine therapeutic advances and their possible future clinical applicability in autoimmunity. MATERIALS AND METHODS: A search was performed in PubMed with the keywords "Chimeric Antigen Receptor" and "CART cell". The documents of interest were selected, and a critical review of the information was carried out. RESULTS: In the treatment of autoimmune diseases, in preclinical models, three different cellular strategies have been used, which include Chimeric antigen receptor T cells, Chimeric autoantibody receptor T cells, and Chimeric antigen receptor in regulatory T lymphocytes. All three types of therapy have been effective. The potential adverse effects within them, cytokine release syndrome, cellular toxicity and neurotoxicity must always be kept in mind. CONCLUSIONS: Although information in humans is not yet available, preclinical models of CAR-T cells in the treatment of autoimmune diseases show promising results, so that in the future, they may become a useful and effective therapy in the treatment of these pathologies.

CAR-T cells leave the comfort zone: current and future applications beyond cancer.

Chimeric antigen receptor (CAR)-T cell therapy represents a breakthrough in the immunotherapy field and has achieved great success following its approval in 2017 for the treatment of B cell malignancies. While CAR-T cells are mostly applied as anti-tumor therapy in the present, their initial concept was aimed at a more general purpose of targeting membrane antigens, thus translating in many potential applications. Since then, several studies have assessed the use of CAR-T cells toward non-malignant pathologies such as autoimmune diseases, infectious diseases and, more recently, cardiac fibrosis, and cellular senescence. In this review, we present the main findings and implications of CAR-based therapies for non-malignant conditions.

Glucuronoxylomannan in the Cryptococcus species capsule as a target for Chimeric Antigen Receptor T-cell therapy.

BACKGROUND AIMS: The genus Cryptococcus comprises two major fungal species that cause clinical infections in humans: Cryptococcus gattii and Cryptococcus neoformans. To establish invasive human disease, inhaled cryptococci must penetrate the lung tissue and reproduce. Each year, about 1 million cases of Cryptococcus infection are reported worldwide, and the infection's mortality rate ranges from 20% to 70%. Many HIV+/AIDS patients are affected by Cryptococcus infections, with 220,000 cases of cryptococcal meningitis reported worldwide in this population every year (C. neoformans infection statistics, via the Centers for Disease Control and Prevention, https://www.cdc.gov/fungal/diseases/cryptococcosis-neoformans/statistics.html). To escape from host immune cell attack, Cryptococcus covers itself in a sugar-based capsule composed primarily of glucuronoxylomannan (GXM). To evade phagocytosis, yeast cells increase to a >45-µm perimeter and become titan, or giant, cells. Cryptococci virulence is directly proportional to the percentage of titan/giant cells present during Cryptococcus infection. To combat cryptococcosis, the authors propose the redirection of CD8+ T cells to target the GXM in the capsule via expression of a GXM-specific chimeric antigen receptor (GXMR-CAR). RESULTS: GXMR-CAR has an anti-GXM single-chain variable fragment followed by an IgG4 stalk in the extracellular domain, a CD28 transmembrane domain and CD28 and CD3-ς signaling domains. After lentiviral transduction of human T cells with the GXMR-CAR construct, flow cytometry demonstrated that 82.4% of the cells expressed GXMR-CAR on their surface. To determine whether the GXMR-CAR+ T cells exhibited GXM-specific recognition, these cells were incubated with GXM for 24 h and examined with the use of brightfield microscopy. Large clusters of proliferating GXMR-CAR+ T cells were observed in GXM-treated cells, whereas no clusters were observed in control cells. Moreover, the interaction of GXM with GXMR-CAR+ T cells was detected via flow cytometry by using a GXM-specific antibody, and the recognition of GXM by GXMR-CAR T cells triggered the secretion of granzyme and interferon gamma (IFN-γ). The ability of GXMR-CAR T cells to bind to the yeast form of C. neoformans was detected by fluorescent microscopy, but no binding was detected in mock-transduced control T cells (NoDNA T cells). Moreover, lung tissue sections were stained with Gomori Methenamine Silver and evaluated by NanoZoomer (Hamamatsu), revealing a significantly lower number of titan cells, with perimeters ranging from 50 to 130 µm and giant cells >130 µm in the CAR T-cell treated group when compared with other groups. Therefore, the authors validated the study's hypothesis by the redirection of GXMR-CAR+ T cells to target GXM, which induces the secretion of cytotoxic granules and IFN-γ that will aid in the control of cryptococcosis CONCLUSIONS: Thus, these findings reveal that GXMR-CAR+ T cells can target C. neoformans. Future studies will be focused on determining the therapeutic efficacy of GXMR-CAR+ T cells in an animal model of cryptococcosis.