RESUMEN
Constitutive NF-κB activation (NF-κBCA) confers survival and proliferation advantages to cancer cells and frequently occurs in T/B cell malignancies including adult T cell leukemia (ATL) caused by human T-cell leukemia virus type 1 (HTLV-1). Counterintuitively, NF-κBCA by the HTLV-1 transactivator/oncoprotein Tax induces a senescence response, and HTLV-1 infections in culture mostly result in senescence or cell-cycle arrest due to NF-κBCA How NF-κBCA induces senescence, and how ATL cells maintain NF-κBCA and avert senescence, remain unclear. Here we report that NF-κBCA by Tax increases R-loop accumulation and DNA double-strand breaks, leading to senescence. R-loop reduction via RNase H1 overexpression, and short hairpin RNA silencing of two transcription-coupled nucleotide excision repair (TC-NER) endonucleases that are critical for R-loop excision-Xeroderma pigmentosum F (XPF) and XPG-attenuate Tax senescence, enabling HTLV-1-infected cells to proliferate. Our data indicate that ATL cells are often deficient in XPF, XPG, or both and are hypersensitive to ultraviolet irradiation. This TC-NER deficiency is found in all ATL types. Finally, ATL cells accumulate R-loops in abundance. Thus, TC-NER deficits are positively selected during HTLV-1 infection because they facilitate the outgrowth of infected cells initially and aid the proliferation of ATL cells with NF-κBCA later. We suggest that TC-NER deficits and excess R-loop accumulation represent specific vulnerabilities that may be targeted for ATL treatment.
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Daño del ADN , Reparación del ADN , ADN de Neoplasias/metabolismo , Productos del Gen tax/metabolismo , Virus Linfotrópico T Tipo 1 Humano/metabolismo , Leucemia-Linfoma de Células T del Adulto/metabolismo , FN-kappa B/metabolismo , Proteínas de Neoplasias/metabolismo , ADN de Neoplasias/genética , Productos del Gen tax/genética , Células HeLa , Virus Linfotrópico T Tipo 1 Humano/genética , Humanos , Leucemia-Linfoma de Células T del Adulto/genética , Leucemia-Linfoma de Células T del Adulto/virología , FN-kappa B/genética , Proteínas de Neoplasias/genéticaRESUMEN
The diagnosis of leukemic B-cell lymphoproliferative disorders (B-LPDs) is made by integrating clinical, cytological, cytometric, cytogenetic, and molecular data. This leaves room for differences and inconsistencies between experts. In this study, we examine methodological and conceptual aspects of the flow cytometric classification of leukemic B-LPDs that could explain them. Among methodological aspects, we discuss (1) the different statistical tests used to select and evaluate markers, (2) how these markers are analyzed, (3) how scores are interpreted, (4) different degrees to which diagnostic information is used, and (5) and the impact of differences in study populations. Among conceptual aspects, we discuss (1) challenges to integrating different biological data points, (2) the under examination of the costs of misclassification (false positives and false negatives), and finally, (3) we delve into the impact of the lack of a true diagnostic gold standard and the indirect evidence suggesting poor reproducibility in the diagnosis of leukemic B-LPDs. We then outline current harmonization efforts and our personal approach. We conclude that numerous flow cytometry scores and diagnostic systems are now available; however, as long as the considerations discussed remain unaddressed, external reproducibility and interobserver agreement will not be achieved, and the field will not be able to move forward if a true gold standard is not found.
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Trastornos Linfoproliferativos , Humanos , Citometría de Flujo , Reproducibilidad de los Resultados , Trastornos Linfoproliferativos/diagnósticoRESUMEN
Immune checkpoint inhibitors are a powerful new tool in the treatment of cancer, with prolonged responses in multiple diseases, including hematologic malignancies, such as Hodgkin lymphoma. However, in a recent report, we demonstrated that the PD-1 inhibitor nivolumab led to rapid progression in patients with adult T-cell leukemia/lymphoma (ATLL) (NCT02631746). We obtained primary cells from these patients to determine the cause of this hyperprogression. Analyses of clonality, somatic mutations, and gene expression in the malignant cells confirmed the report of rapid clonal expansion after PD-1 blockade in these patients, revealed a previously unappreciated origin of these malignant cells, identified a novel connection between ATLL cells and tumor-resident regulatory T cells (Tregs), and exposed a tumor-suppressive role for PD-1 in ATLL. Identifying the mechanisms driving this alarming outcome in nivolumab-treated ATLL may be broadly informative for the growing problem of rapid progression with immune checkpoint therapies.
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Antineoplásicos Inmunológicos/uso terapéutico , Leucemia-Linfoma de Células T del Adulto/tratamiento farmacológico , Nivolumab/uso terapéutico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Linfocitos T Reguladores/patología , Adulto , Animales , Progresión de la Enfermedad , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , Humanos , Leucemia-Linfoma de Células T del Adulto/genética , Leucemia-Linfoma de Células T del Adulto/patología , Ratones , Linfocitos T Reguladores/efectos de los fármacos , Linfocitos T Reguladores/metabolismo , Células Tumorales CultivadasRESUMEN
Thyroglobulin is a glycoiodoprotein that is produced by thyroid follicular cells; it is stored in follicles in structures known as colloids. The main function of this protein is to stock the hormones triiodothyronine (T3) and thyroxine (T4) until the body requires them. This study aims to demonstrate that infrared spectral imaging with appropriate multivariate analysis can reveal biochemical changes in this glycoprotein. The results achieved herein point out biochemical differences in the colloid samples obtained from normal and goiter patients including glycosylation and changes in the secondary conformational structure. We have presented the first spectral histopathology-based method to detect biochemical differences in thyroid colloids, such as TG iodination, glycosylation, and changes in the secondary structure in normal and goiter patients. The observed changes in the colloids were mainly due to the alterations in amide I and amide II (secondary conformation of proteins) and there is a correlation with different glycosylation between normal and goiter tissues.
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Bocio , Tiroglobulina , Bocio/diagnóstico por imagen , Humanos , Espectrofotometría Infrarroja , Tiroxina , TriyodotironinaRESUMEN
New technologies to diagnose malaria at high sensitivity and specificity are urgently needed in the developing world where the disease continues to pose a huge burden on society. Infrared and Raman spectroscopy-based diagnostic methods have a number of advantages compared with other diagnostic tests currently on the market. These include high sensitivity and specificity for detecting low levels of parasitemia along with ease of use and portability. Here, we review the application of vibrational spectroscopic techniques for monitoring and detecting malaria infection. We discuss the role of vibrational (infrared and Raman) spectroscopy in understanding the processes of parasite biology and its application to the study of interactions with antimalarial drugs. The distinct molecular phenotype that characterizes malaria infection and the high sensitivity enabling detection of low parasite densities provides a genuine opportunity for vibrational spectroscopy to become a front-line tool in the elimination of this deadly disease and provide molecular insights into the chemistry of this unique organism.
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Malaria/diagnóstico , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Espectrometría Raman/métodos , Animales , Eritrocitos/microbiología , Eritrocitos/patología , Hemo/análisis , Hemoproteínas/análisis , Humanos , Plasmodium/crecimiento & desarrollo , Espectroscopía Infrarroja por Transformada de Fourier/instrumentación , Espectrometría Raman/instrumentación , VibraciónRESUMEN
Dose-adjusted-EPOCH-R obviates the need for radiotherapy in most patients with primary mediastinal B-cell lymphoma. End-of-treatment PET, however, does not accurately identify patients at risk of treatment failure, thereby confounding clinical decision making. To define the role of PET in primary mediastinal B-cell lymphoma following dose-adjusted-EPOCH-R, we extended enrollment and follow up on our published phase II trial and independent series. Ninety-three patients received dose-adjusted-EPOCH-R without radiotherapy. End-of-treatment PET was performed in 80 patients, of whom 57 received 144 serial scans. One nuclear medicine physician from each institution blindly reviewed all scans from their respective institution. End-of-treatment PET was negative (Deauville 1-3) in 55 (69%) patients with one treatment failure (8-year event-free and overall survival of 96.0% and 97.7%). Among 25 (31%) patients with a positive (Deauville 4-5) end-of-treatment PET, there were 5 (20%) treatment failures (8-year event-free and overall survival of 71.1% and 84.3%). Linear regression analysis of serial scans showed a significant decrease in SUVmax in positive end-of-treatment PET non-progressors compared to an increase in treatment failures. Among 6 treatment failures, the median end-of-treatment SUVmax was 15.4 (range, 1.9-21.3), and 4 achieved long-term remission with salvage therapy. Virtually all patients with a negative end-of-treatment PET following dose-adjusted-EPOCH-R achieved durable remissions and should not receive radiotherapy. Among patients with a positive end-of-treatment PET, only 5/25 (20%) had treatment-failure. Serial PET imaging distinguished end-of-treatment PET positive patients without treatment failure, thereby reducing unnecessary radiotherapy by 80%, and should be considered in all patients with an initial positive PET following dose-adjusted-EPOCH-R (clinicaltrials.gov identifier 00001337).
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Toma de Decisiones Clínicas/métodos , Linfoma de Células B Grandes Difuso/diagnóstico por imagen , Linfoma de Células B Grandes Difuso/terapia , Tomografía de Emisión de Positrones/métodos , Adolescente , Adulto , Anciano , Ciclofosfamida/uso terapéutico , Diagnóstico Diferencial , Doxorrubicina/uso terapéutico , Etopósido/uso terapéutico , Femenino , Humanos , Linfoma de Células B Grandes Difuso/mortalidad , Masculino , Neoplasias del Mediastino/diagnóstico por imagen , Neoplasias del Mediastino/mortalidad , Neoplasias del Mediastino/terapia , Persona de Mediana Edad , Prednisona/uso terapéutico , Rituximab/uso terapéutico , Análisis de Supervivencia , Insuficiencia del Tratamiento , Resultado del Tratamiento , Vincristina/uso terapéutico , Adulto JovenRESUMEN
Traditional methods for identifying pathogens in bacteremic patients are slow (24-48+ h). This can lead to physicians making treatment decisions based on an incomplete diagnosis and potentially increasing the patient's mortality risk. To decrease time to diagnosis, we have developed a novel technology that can recover viable bacteria directly from whole blood and identify them in less than 7 h. Our technology combines a sample preparation process with surface-enhanced Raman spectroscopy (SERS). The sample preparation process enriches viable microorganisms from 10 mL of whole blood into a 200 µL aliquot. After a short incubation period, SERS is used to identify the microorganisms. We further demonstrated that SERS can be used as a broad detection method, as it identified a model set of 17 clinical blood culture isolates and microbial reference strains with 100% identification agreement. By applying the integrated technology of sample preparation and SERS to spiked whole blood samples, we were able to correctly identify both Staphylococcus aureus and Escherichia coli 97% of the time with 97% specificity and 88% sensitivity.
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Escherichia coli/aislamiento & purificación , Staphylococcus aureus/aislamiento & purificación , Humanos , Espectrometría Raman/instrumentación , Propiedades de SuperficieRESUMEN
Adults with cancer commonly develop severe lymphopenia two months following chemoradiation therapy, which is an independent predictor of survival. In this retrospective study of 53 children with central nervous system tumors and sarcomas, the frequency, severity, and duration of radiation-associated lymphopenia was similar to that seen in adults. Pretreatment lymphocyte counts were 1,000 cells/mm(3) or greater in all patients, with 66% experiencing grade III-IV lymphopenia two months after chemoradiation. Lymphocyte counts remained significantly lower than baseline 12 months later. Further studies are needed to determine if this is also associated with poorer survival, as seen in adults.
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Linfopenia/diagnóstico , Linfopenia/etiología , Neoplasias/complicaciones , Radioterapia/efectos adversos , Adolescente , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Niño , Preescolar , Femenino , Humanos , Recuento de Linfocitos , Masculino , Neoplasias/diagnóstico , Neoplasias/tratamiento farmacológico , Neoplasias/radioterapia , Radioterapia/métodos , Adulto JovenRESUMEN
Instrumental advances in infrared micro-spectroscopy have made possible the observation of individual human cells and even subcellular structures. The observed spectra represent a snapshot of the biochemical composition of a cell; this composition varies subtly but reproducibly with cellular effects such as progression through the cell cycle, cell maturation and differentiation, and disease. The aim of this summary is to provide a synopsis of the progress achieved in infrared spectral cytopathology (SCP) - the combination of infrared micro-spectroscopy and multivariate methods of analysis - for the detection of abnormalities in exfoliated human cells of the upper respiratory and digestive tract, namely the oral and nasopharyngeal cavities, and the esophagus.
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Neoplasias Esofágicas/patología , Tamizaje Masivo/métodos , Neoplasias de la Boca/patología , Neoplasias Nasofaríngeas/patología , Espectrofotometría Infrarroja/métodos , Células Epiteliales/patología , Neoplasias Esofágicas/diagnóstico , Humanos , Neoplasias de la Boca/diagnóstico , Neoplasias Nasofaríngeas/diagnósticoRESUMEN
We report results of a study utilizing a novel tissue classification method, based on label-free spectral techniques, for the classification of lung cancer histopathological samples on a tissue microarray. The spectral diagnostic method allows reproducible and objective classification of unstained tissue sections. This is accomplished by acquiring infrared data sets containing thousands of spectra, each collected from tissue pixels â¼6 µm on edge; these pixel spectra contain an encoded snapshot of the entire biochemical composition of the pixel area. The hyperspectral data sets are subsequently decoded by methods of multivariate analysis that reveal changes in the biochemical composition between tissue types, and between various stages and states of disease. In this study, a detailed comparison between classical and spectral histopathology is presented, suggesting that spectral histopathology can achieve levels of diagnostic accuracy that is comparable to that of multipanel immunohistochemistry.
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Técnicas Histológicas/métodos , Neoplasias Pulmonares/clasificación , Neoplasias Pulmonares/patología , Espectrofotometría Infrarroja/métodos , Análisis de Matrices Tisulares/métodos , Humanos , Análisis MultivarianteRESUMEN
We report results from a study utilizing infrared spectral cytopathology (SCP) to detect abnormalities in exfoliated esophageal cells. SCP has been developed over the past decade as an ancillary tool to classical cytopathology. In SCP, the biochemical composition of individual cells is probed by collecting infrared absorption spectra from each individual, unstained cell, and correlating the observed spectral patterns, and the variations therein, against classical diagnostic methods to obtain an objective, machine-based classification of cells. In the past, SCP has been applied to the analysis and classification of cells exfoliated from the cervix and the oral cavity. In these studies, it was established that SCP can distinguish normal and abnormal cell types. Furthermore, SCP can differentiate between truly normal cells, and cells with normal morphology from the vicinity of abnormalities. Thus, SCP may be a valuable tool for the screening of early stages of dysplasia and pre-cancer.
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Esófago/citología , Esófago/patología , Imagen Óptica , Esófago de Barrett/diagnóstico , Esófago de Barrett/patología , Humanos , Espectrofotometría InfrarrojaRESUMEN
In this paper, we report the spectral patterns of normal human thyroid tissue and methodology to interpret hyperspectral imaging data and protein conformational changes observed therein. Raw image datasets were imported into software written in-house in the MATLAB environment and processed to yield pseudo-color images of the tissue sections. All spectra were vector normalized, noise-filtered, and corrected for water-vapour contributions and scattering effects before being subjected to Hierarchical Cluster Analysis (HCA) and correlated with histological structures obtained from images of H&E-stained parallel tissue sections. We successfully identified a protein structural heterogeneity that can be correlated with the spatially resolved amount of iodine in the thyroglobulin structure of colloids and follicular cells.
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Espectroscopía Infrarroja por Transformada de Fourier/métodos , Glándula Tiroides/química , Humanos , Hormonas Tiroideas/análisis , Análisis de Matrices TisularesRESUMEN
This paper presents a short review on the improvements in data processing for spectral cytopathology, the diagnostic method developed for large scale diagnostic analysis of spectral data of individual dried and fixed cells. This review is followed by the analysis of the confounding effects introduced by utilizing reflecting "low-emissivity" (low-e) slides as sample substrates in infrared micro-spectroscopy of biological samples such as individual dried cells or tissue sections. The artifact introduced by these substrates, referred to as the "standing electromagnetic wave" artifact, indeed, distorts the spectra noticeably, as postulated recently by several research groups. An analysis of the standing wave effect reveals that careful data pre-processing can reduce the spurious effects to a level where they are not creating a major problem for spectral cytopathology and spectral histopathology.
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Diagnóstico por Imagen/métodos , Neoplasias de la Boca/diagnóstico , Lesiones Precancerosas/diagnóstico , Espectrofotometría Infrarroja/métodos , Lengua/citología , Algoritmos , Estudios de Casos y Controles , HumanosRESUMEN
Scientific bias originates from both researchers and techniques. Evidence-based strategies to mitigate this bias include the assembly of diverse teams, development of rigorous experimental designs, and use of unbiased analytical techniques. Here, we highlight potential starting points to decrease bias in bioengineering research.
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Importance: Many economic theories point to regulatory issues and subsidization of research and development costs as the primary factor in the high cancer drug prices in the US. Even so, the association between the median annual cost and novelty of cancer drugs approved in the US remains unclear. Objective: To evaluate the association between the median annual cost and novelty of cancer drugs approved in the US over a 6-year period. Design, Setting, and Participants: This cross-sectional study included all cancer drugs approved by the US Food and Drug Administration (FDA) from January 1, 2015, to December 31, 2020. Drug names, indications, manufacturer, dosage, and measures of activity/efficacy were extracted from the FDA announcement. The search was performed in December 2021. Data were analyzed from January 2022 until April 2022. Main Outcomes and Measures: Annual cost of treatment was calculated based on average wholesale price collected from the 2021 Micromedex Red Book database. Mechanism of action was inferred from trial publication or its references. Results: There were 224 cancer drug approvals across 119 individual drugs, with a median annual cost of $196â¯000 (IQR, $170â¯000-$277â¯000). Gene and viral therapies were the most expensive (median, $448â¯000 [IQR, $448â¯000-$479â¯000]), followed by small molecule therapy (median, $244â¯000 [IQR, $203â¯000-$321â¯000), and biologics (median, $185â¯000 [IQR, $148â¯000-$195â¯000]). There was no significant difference in cost between first-in-class, next-in-class, and subsequent approvals of an already approved drug. Conclusions and Relevance: Findings of this study indicate that the median annual price of anticancer drugs in the US is not associated with the novelty of their mechanism of action.
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Antineoplásicos , Neoplasias , Humanos , Estudios Transversales , Antineoplásicos/uso terapéutico , Neoplasias/tratamiento farmacológico , Preparaciones Farmacéuticas , Factores Biológicos/uso terapéuticoRESUMEN
Interleukin-15 (IL-15) monotherapy substantially increases the number and activity of natural killer (NK) cells and CD8+ T cells but has not produced clinical responses. In a xenograft mouse model, IL-15 enhanced the NK cell-mediated antibody-dependent cell cytotoxicity (ADCC) of the anti-CD52 antibody alemtuzumab and led to significantly more durable responses than alemtuzumab alone. To evaluate whether IL-15 potentiates ADCC in humans, we conducted a phase 1 single-center study of recombinant human IL-15 and alemtuzumab in patients with CD52-positive mature T-cell malignances. We gave IL-15 subcutaneously 5 days per week for 2 weeks in a 3 + 3 dose escalation scheme (at 0.5, 1, and 2 µg/kg), followed by standard 3 times weekly alemtuzumab IV for 4 weeks. There were no dose-limiting toxicities or severe adverse events attributable to IL-15 in the 11 patients treated. The most common adverse events were lymphopenia (100%), alemtuzumab-related infusion reactions (90%), anemia (90%), and neutropenia (72%). There were 3 partial and 2 complete responses, with an overall response rate of 45% and median duration of response 6 months. Immediately after 10 days of IL-15, there was a median 7.2-fold increase in NK cells and 2.5-fold increase in circulating CD8+ T cells, whereas the number of circulating leukemic cells decreased by a median 38% across all dose levels. Treatment with IL-15 was associated with increased expression of NKp46 and NKG2D, markers of NK-cell activation, and increased ex vivo ADCC activity of NK cells, whereas inhibitory receptors PD1 and Tim3 were decreased. This trial was registered at www.clinicaltrials.gov as #NCT02689453.
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Interleucina-15 , Neoplasias , Humanos , Animales , Ratones , Alemtuzumab/uso terapéutico , Anticuerpos Monoclonales/uso terapéutico , Células Asesinas Naturales , Citotoxicidad Celular Dependiente de Anticuerpos , Factores Inmunológicos , Neoplasias/tratamiento farmacológico , Antígeno CD52/metabolismoRESUMEN
BACKGROUND: Chimeric antigen receptor (CAR) T cells are highly effective in treating haematological malignancies, but associated toxicities and the need for lymphodepletion limit their use in people with autoimmune disease. To explore the use of CAR T cells for the treatment of people with autoimmune disease, and to improve their safety, we engineered them with RNA (rCAR-T)-rather than the conventional DNA approach-to target B-cell maturation antigen (BCMA) expressed on plasma cells. To test the suitability of our approach, we used rCAR-T to treat individuals with myasthenia gravis, a prototypical autoantibody disease mediated partly by pathogenic plasma cells. METHODS: MG-001 was a prospective, multicentre, open-label, phase 1b/2a study of Descartes-08, an autologous anti-BCMA rCAR-T therapy, in adults (ie, aged ≥18 years) with generalised myasthenia gravis and a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 6 or higher. The study was done at eight sites (ie, academic medical centres or community neurology clinics) in the USA. Lymphodepletion chemotherapy was not used. In part 1 (phase 1b), participants with Myasthenia Gravis Foundation of America (MGFA) disease class III-IV generalised myasthenia gravis received three ascending doses of Descartes-08 to determine a maximum tolerated dose. In part 2 (phase 2a), participants with generalised myasthenia gravis with MGFA disease class II-IV received six doses at the maximum tolerated dose in an outpatient setting. The primary objective was to establish safety and tolerability of Descartes-08; secondary objectives were to assess myasthenia gravis disease severity and biomarkers in participants who received Descartes-08. This trial is registered with clinicaltrials.gov, NCT04146051. FINDINGS: We recruited 16 individuals for screening between Jan 7, 2020 and Aug 3, 2022. 14 participants were enrolled (n=3 in part 1, n=11 in part 2). Ten participants were women and four were men. Two individuals did not qualify due to low baseline MG-ADL score (n=1) or lack of generalised disease (n=1). Median follow-up in part 2 was 5 months (range 3-9 months). There was no dose-limiting toxicity, cytokine release syndrome, or neurotoxicity. Common adverse events were headache (six of 14 participants), nausea (five of 14), vomiting (three of 14), and fever (four of 14), which resolved within 24 h of infusion. Fevers were not associated with increased markers of cytokine release syndrome (IL-6, IL-2, and TNF). Mean improvements from baseline to week 12 were -6 (95% CI -9 to -3) for MG-ADL score, -7 (-11 to -3) for Quantitative Myasthenia Gravis score, -14 (-19 to -9) for Myasthenia Gravis Composite score, and -9 (-15 to -3) for Myasthenia Gravis Quality of Life 15-revised score. INTERPRETATION: In this first study of an rCAR-T therapy in individuals with an autoimmune disease, Descartes-08 appeared to be safe and was well tolerated. Descartes-08 infusions were followed by clinically meaningful decreases on myasthenia gravis severity scales at up to 9 months of follow-up. rCAR-T therapy warrants further investigation as a potential new treatment approach for individuals with myasthenia gravis and other autoimmune diseases. FUNDING: Cartesian Therapeutics and National Institute of Neurological Disorders and Stroke of the National Institutes of Health.
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Miastenia Gravis , Receptores Quiméricos de Antígenos , Adolescente , Adulto , Femenino , Humanos , Masculino , Actividades Cotidianas , Autoanticuerpos , Tratamiento Basado en Trasplante de Células y Tejidos , Síndrome de Liberación de Citoquinas , Miastenia Gravis/tratamiento farmacológico , Estudios Prospectivos , Calidad de Vida , Receptores Quiméricos de Antígenos/uso terapéutico , Resultado del TratamientoRESUMEN
Spectral cytopathology (SCP) is a novel approach for disease diagnosis that utilizes infrared spectroscopy to interrogate the biochemical components of cellular samples and multivariate statistical methods, such as principal component analysis, to analyze and diagnose spectra. SCP has taken vast strides in its application for disease diagnosis over the past decade; however, fixation-induced changes and sample handling methods are still not systematically understood. Conversely, fixation and staining methods in conventional cytopathology, typically involving protocols to maintain the morphology of cells, have been documented and widely accepted for nearly a century. For SCP, fixation procedures must preserve the biochemical composition of samples so that spectral changes significant to disease diagnosis are not masked. We report efforts to study the effects of fixation protocols commonly used in traditional cytopathology and SCP, including fixed and unfixed methods applied to exfoliated oral (buccal) mucosa cells. Data suggest that the length of time in fixative and duration of sample storage via desiccation contribute to minor spectral changes where spectra are nearly superimposable. These findings illustrate that changes influenced by fixation are negligible in comparison to changes induced by disease.
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Mucosa Bucal/patología , Fijación del Tejido , Fosfatos de Calcio/química , Humanos , Enfermedades de la Boca/diagnóstico , Enfermedades de la Boca/patología , Análisis de Componente Principal , Factores de TiempoRESUMEN
Spectral cytopathology (SCP) is a robust and reproducible diagnostic technique that employs infrared spectroscopy and multivariate statistical methods, such as principal component analysis to interrogate unstained cellular samples and discriminate changes on the biochemical level. In the past decade, SCP has taken considerable strides in its application for disease diagnosis. Cultured cell lines have proven to be useful model systems to provide detailed biological information to this field; however, the effects of sample fixation and storage of cultured cells are still not entirely understood in SCP. Conventional cytopathology utilizes fixation and staining methods that have been established and widely accepted for nearly a century and are focused on maintaining the morphology of a cell. Conversely, SCP practices must implement fixation protocols that preserve the sample's biochemical composition and maintain its spectral integrity so not to introduce spectral changes that may mask variance significant to disease. It is not only necessary to evaluate the effects on fixed exfoliated cells but also fixed cultured cells because although they are similar systems, they exhibit distinct differences. We report efforts to study the effects of fixation methodologies commonly used in traditional cytopathology and SCP including both fixed and unfixed routines applied to cultured HeLa cells, an adherent cervical cancer cell line. Data suggest parallel results to findings in Part 1 of this series for exfoliated cells, where the exposure time in fixative and duration of sample storage via desiccation contribute to minor spectral changes only. The results presented here reinforce observations from Part 1 indicating that changes induced by disease are much greater than changes observed as a result of alternate fixation methodologies. Principal component analysis of HeLa cells fixed via the same conditions and protocols as exfoliated cells (Part 1) yield nearly identical results. More importantly, the overall conclusion is that it is necessary that all samples subjected to comparative analysis should be prepared identically because although changes are minute, they are present.