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MIC-A and MIC-B are the natural ligands for NKG2D, an activator receptor expressed in NK cells. Soluble isoforms of MIC-A and MIC-B (sMICA, sMICB) have been identified in different malignancies, affecting NK cells' cytotoxicity. The study was performed to determine the levels of sMICA, sMICB, the expression of MIC-A, and MIC-B on tumor tissues, and lymphocyte subpopulations (CD4 + , CD8 + , NK, NKT, Tγδ cells, B cells, monocytes) in 94 patients with non-Hodgkin's lymphoma (NHL) and 72 healthy donors.The most frequent lymphoma was diffuse large B cell lymphoma (48%). Patients with NHL had decreased numbers of CD4 T cells, CD8 T cells, B cells, monocytes, NK cells, type 1 dendritic cells, γδ T cells, and increased iNKT cells. Patients showed higher levels of sMIC-A and similar serum levels of sMIC-B.Survival was poorer in patients having higher LDH values and lower numbers of CD4 T cells, type 1 dendritic cells, gamma-delta T cells, and high levels of sMIC-A.In conclusion, high levels of sMIC and decreased numbers in circulating lymphocyte subsets are related to poor outcomes in NHL.
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Linfoma Difuso de Grandes Células B , Linfoma não Hodgkin , Humanos , Prognóstico , Linfoma não Hodgkin/patologia , Subpopulações de Linfócitos , Células Matadoras Naturais/patologia , Linfoma Difuso de Grandes Células B/patologiaRESUMO
Diffuse large B-cell lymphoma (DLBCL) is the most frequent lymphoma. MIC-A and MIC-B are the natural ligands for NKG2D, a receptor expressed in NK cells. MIC-A soluble isoforms (sMICA) have been described in different malignancies. OBJECTIVES: To analyze lymphocyte subsets and sMIC-A in germinal center DLBCL. MATERIALS AND METHODS: sMICA, sMICB, and peripheral blood lymphocyte subsets (CD4+, CD8+, NK, NKT, γδ T cells, and dendritic cells) were analyzed in 59 patients and 60 healthy donors. RESULTS: Patients had decreased numbers of type 1 and type 2 dendritic cells, NK, iNKT, CD4 T, and CD8 T cells, and higher levels of sMIC-A. The 2-year PFS for high IPI scores and high sMIC-A was 24% and 28%, respectively. The 2-year OS for high IPI scores and high sMIC-A was 42% and 33%. The 2-year PFS and OS for patients not achieving response to treatment were 0% and 10%, respectively. The MICPI score (one point each for high IPI score and high sMIC-A) showed that those patients summing two points had worse PSF and OS. CONCLUSIONS: Patients with DLBCL have decreased numbers of peripheral lymphocyte subsets and high levels of sMIC-A. The addition of sMIC-A to IPI could improve its prognostic relevance.
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Centro Germinativo , Linfoma Difuso de Grandes Células B , Humanos , Linfoma Difuso de Grandes Células B/mortalidade , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/diagnóstico , Linfoma Difuso de Grandes Células B/sangue , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Prognóstico , Centro Germinativo/patologia , Centro Germinativo/metabolismo , Adulto , Subpopulações de Linfócitos/metabolismo , Subpopulações de Linfócitos/imunologia , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resultado do Tratamento , Estadiamento de Neoplasias , Imunofenotipagem , Biomarcadores TumoraisRESUMO
INTRODUCTION: Alloimmunization is caused by exposure to erythrocytes from a donor that expresses blood group antigens other than those of the recipient and is related to processes that alter the balance of the immune system. Knowing the pathophysiology of alloimmunization process is essential to understand clinical complications associated with this process. PATIENTS AND METHODS: From October 2016 to April 2017, irregular antibody screening was performed in 1,434 polytransfused (compatible with the ABO and D system) patients by means of agglutination techniques using erythrocytes of a known phenotype of 44 patients with a positive alloantibody screening. Non-alloimmunized (control) subjects were matched for age, gender, pathology, and treatment group with alloimmunized patients. The subsets of B, T, and Treg lymphocytes were determined by flow cytometry. RESULTS: The results of screening for alloantibodies in patients by specificity of antibodies were as follows: nonspecific (30%), followed by anti-Dia (13%), anti-e (9%), anti-S (9%), anti-I (7%), anti-K (7%), and anti-P (7%). A lower percentage of CD4+ T lymphocytes and an increase of CD8+ T lymphocytes were observed in alloimmunized patients, as well as a low CD4/CD8 ratio (0.7 vs. 1.6, p = 0.003), a higher percentage of B lymphocytes versus the control group (30 vs. 20%, p = 0.003), and a decrease of Treg CD4+ lymphocytes versus the control group (3 vs. 12 cells/µL, p = 0.043). These observations suggest that alloimmunized patients have important alterations in the number of some lymphocyte subsets that can be translated into clinical immune dysregulation. CONCLUSION: A decreased CD4/CD8 ratio, increased B lymphocytes, and Treg lymphocyte deficiency are the most significant changes observed in alloimmunized patients.
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BACKGROUND: One of the major limitations of umbilical cord blood (UCB) as hematopoietic stem cell source is its restricted cell number. In mothers who are candidates for stem cell donation, there are variables that affect the quantity and quality of UCB units. The aim of this study was to determine if obstetric, maternal, and fetal factors modify the number of lymphocyte subsets in UCB units. STUDY DESIGN AND METHODS: This was a prospective, observational study. In UCB units, the numbers of CD34, NK, NKT, iNKT, Type 1 dendritic cells (DCs), Type 2 DCs, T γδ, T CD4+, T CD8+ lymphocytes, CD4+CD25+FoxP3+, and CD8+CD25+FoxP3+ T regulatory (Treg) cells were quantified by flow cytometry. RESULTS: Fifty-four UCB units were included; the donors' mean weight was 75 kg (range, 52 to 102 kg) and they had a mean body mass index (BMI) of 30 kg/m(2) (range 22 to 40 kg/m(2) ), of which 12 (22%) had a normal BMI, 14 (26%) were overweight, and 28 (52%) were obese. The mean number of CD34+ cells was 4.45 × 10(6) (range, 0.7 × 10(6) to 20.5 × 10(6) ). The number of NKT, CD3+, CD4+, CD8+, and CD8+CD25+FoxP3+ Treg cells was significantly higher in overweight or obese mothers; CD34+ cells were decreased in the same group. The number of iNKT and CD34+ cells was decreased in newborns weighing above the average. CONCLUSIONS: Maternal factors such as BMI, and fetal factors such as weight at birth, should be added to the selection criteria of UCB donors.
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Sangue Fetal/citologia , Contagem de Linfócitos , Obesidade/imunologia , Adolescente , Adulto , Linfócitos T CD8-Positivos/citologia , Seleção do Doador/métodos , Feminino , Humanos , Células T Matadoras Naturais/citologia , Obesidade/sangue , Gravidez , Estudos Prospectivos , Inquéritos e Questionários , Linfócitos T Reguladores/citologia , Adulto JovemRESUMO
Non-Hodkin's lymphoma (NHL) is the most frequent hematologic malignancy in humans and dogs. NKG2D is one of the most critical receptors on NK cells, recognizing their natural ligands on malignant cells such as A and B major histocompatibility complex-related proteins (MIC-A and MIC-B). Soluble molecules (sMIC-A and sMIC-B) can interfere with immune synapsis between NK cells and tumor cells, impeding NK cytotoxicity. The main objectives of this study were to analyze, in dogs with diffuse large B cell lymphoma, NK cell lymphoma, and reactive lymphadenopathies, the role of NK cells, their activating receptors NKG2D and NKp46, and their ligands MIC-A and MIC-B, as well as soluble molecules sMIC-A and sMIC-B. Thirty-six dogs with a possible diagnosis of NHL and eight healthy dogs were studied. NHL was diagnosed in 28 (78 %) dogs; in the other 8 (22 %), reactive lymphadenopathies were present. Most of the lymphomas corresponded to B cell NHL (82 %). The most predominant subtype was diffuse large B cell lymphoma (21, 71.5 %), followed by five cases (18 %) that were Non-B Non-T lymphomas (presumably NK cell lymphomas) and other B cell lymphomas (3, 10.5%). There were no cases of T cell NHL. MIC-A was positive in 7 of 27 (26 %) cases of NHL, and MIC-B in 20 of 27 (74 %) NHL. In non-malignant lymphadenopathies, three (37.5 %) dogs were positive for MIC-A, and five (62.5 %) expressed MIC-B. Dogs with lymphoma had higher numbers of NK cells than eight healthy dogs. In 15 dogs (12 cases with NHL and three cases with reactive adenopathies) and eight controls, there were no differences in the number of NK cells expressing NKP46 and NKG2D. NHL dogs had higher values of sMIC-A and sMIC-B. B-cell and NK cell lymphomas correspond to 86 % and 14 % of all canine lymphomas. MIC-A, MIC-B, and sMIC-A and sMIC-B were increased in canine lymphomas.
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Doenças do Cão , Linfadenopatia , Linfoma Difuso de Grandes Células B , Animais , Cães , Doenças do Cão/metabolismo , Células Matadoras Naturais , Linfadenopatia/metabolismo , Linfadenopatia/veterinária , Linfoma Difuso de Grandes Células B/veterinária , Linfoma Difuso de Grandes Células B/metabolismo , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismoRESUMO
Background: Adequate glycemic control improves the prognosis of patients hospitalized for pneumonia associated with severe COVID-19. Objective: To evaluate the impact of hyperglycemia (HG) on the prognosis of patients hospitalized for severe pneumonia associated with COVID-19 in unvaccinated patients. Material and methods: Prospective cohort study. We included patients hospitalized from August 2020 to February 2021, with severe COVID-19 pneumonia, not vaccinated against SARS-CoV-2. Data was collected from admission to discharge. We used descriptive and analytical statistics according to the data distribution. ROC curves were used to determine the cut-off points with the highest predictive performance for HG and mortality, with the IBM SPSS program, version 25. Results: We included 103 patients, 32% women, 68% men, age 57 ± 13 years; 58% were admitted with HG (191, IQR 152-300 mg/dL) and 42% with normoglycemia (NG < 126 mg/dL). Mortality was higher in HG at admission 34 (56.7%) than in NG 13 (30.2%) (p = 0.008). HG was associated with diabetes mellitus 2 and neutrophilia (p < 0.05). The risk of death increases 1.558 times (95% CI 1.118-2.172) if HG is at admission and 1.43 times (95% CI 1.14-1.79) during hospitalization. Maintaining NG throughout the hospitalization contributed independently to survival (RR = 0.083 [95% CI 0.012-0.571], p = 0.011). Conclusion: HG significantly impacts prognosis by increasing mortality more than 50% during hospitalization for COVID-19.
Introducción: el adecuado control glucémico mejora el pronóstico de pacientes hospitalizados por neumonía asociada a COVID-19 grave. Objetivo: evaluar el impacto de la hiperglucemia (HG) sobre el pronóstico de pacientes hospitalizados por neumonía grave asociada a COVID-19 en no vacunados. Material y métodos: estudio de cohorte prospectivo. Se incluyeron pacientes hospitalizados de agosto de 2020 a febrero de 2021, con neumonía grave por COVID-19, no vacunados contra SARS-CoV-2. Los datos fueron recolectados desde el ingreso hasta el egreso. Se empleó estadística descriptiva y analítica de acuerdo con la distribución de datos. Se construyeron curvas ROC para determinar los puntos de corte de mayor rendimiento predictivo para HG y mortalidad, con el programa IBM SPSS, versión 25. Resultados: se incluyeron 103 pacientes, 32% mujeres, 68% hombres, edad 57 ± 13 años; 58% ingresaron con HG (191, IQR 152-300 mg/dL) y 42% en normoglucemia (NG < 126 mg/dL). La mortalidad fue mayor en HG al ingreso 34 (56.7%) que en NG 13 (30.2%) (p = 0.008). La HG se asoció con diabetes mellitus 2 y neutrofilia (p < 0.05). El riesgo de muerte se incrementó 1.558 veces (IC 95% 1.118-2.172) si la HG fue al ingreso y 1.43 veces (IC 95% 1.14-1.79) durante la hospitalización. Mantener NG durante todo el internamiento contribuyó de manera independiente a la sobrevida (RR 0.083 [IC 95% 0.012-0.571], p = 0.011). Conclusión: la HG impacta significativamente el pronóstico al incrementar en más de 50% la mortalidad durante la hospitalización por COVID-19.
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COVID-19 , Hiperglicemia , Masculino , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , COVID-19/complicações , COVID-19/terapia , SARS-CoV-2 , Estudos Prospectivos , Hiperglicemia/complicações , Hiperglicemia/diagnóstico , Hospitalização , Prognóstico , Estudos RetrospectivosRESUMO
INTRODUCTION: The BCR-ABL t(9;22)(q34;q11) translocation has been identified as a risk factor in de novo acute lymphoblastic leukemia (ALL), but there are other factors that may influence survival in patients not expressing this translocation. OBJECTIVE: To associate expression and non-expression of BCR-ABL with immunophenotype and other clinical features in adult patients with ALL from a Mexican mestizo population. MATERIAL AND METHODS; Peripheral blood samples from 35 adult patients with de novo ALL were used to detect BCR-ABL by reverse transcriptase polymerase chain reaction (RT-PCR) as well as immunophenotype by flow cytometry. RESULTS: In the group of BCR-ABL negative patients (74.28%) two subgroups were identified with the immature immunophenotypes CD34+/CD33+ and/or CD13+, and CD10-/CD34+. In the group of BCR-ABL positive patients (25.72%) leukemic blast cells with a more differentiated immunophenotype compared to the BCR-ABL negative group were found. As regards clinical and biological characteristics, we found survival in months to be very similar and a tendency to high initial leukocyte counts in both groups. CONCLUSIONS: This is the first study conducted on a Mexican mestizo population to report that BCR-ABL negative patients can present a high frequency of undifferentiated immunophenotypes and must therefore be considered as vulnerable as BCR-ABL positive patients.
Assuntos
Etnicidade/estatística & dados numéricos , Proteínas de Fusão bcr-abl/análise , Imunofenotipagem , Leucemia-Linfoma Linfoblástico de Células Precursoras/etnologia , Adulto , Idoso , Antígenos CD/análise , Biomarcadores Tumorais , Medula Óssea/patologia , Seguimentos , Regulação Leucêmica da Expressão Gênica , Humanos , México/epidemiologia , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/química , Cromossomo Filadélfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/classificação , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Prognóstico , RNA Mensageiro/genética , RNA Neoplásico/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Previous studies demonstrated that the majority of Hodgkin lymphoma (HL) patients achieve response after treatment, while 5% become refractory. Studies analyzing the role of lymphocyte subsets in peripheral blood are limited. This investigation sought to evaluate peripheral blood lymphocyte subsets and soluble MHC class I chain-related proteins A and B (sMIC-A/B) and their correlation with survival in patients with newly diagnosed HL. The study recruited 36 patients and 72 healthy donors. HL patients showed a decrease in CD4, B, monocytes, NK, and NKT cells; and an increase in γ-δ T cells and soluble MIC-A serum levels. Higher values of s-MIC-A >100 ng/mL and NKT cells >40 µL correlated with poor overall survival (OS). In conclusion, in HL peripheral blood CD4 T and B cells, monocytes, NK, and NKT cells were decreased, while s-MIC-A and γ-δ T cells increased. Higher values of s-MIC-A and NKT cells correlated with poor survival.
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Doença de Hodgkin , Células T Matadoras Naturais , Humanos , Contagem de Linfócitos , Subpopulações de Linfócitos , Subpopulações de Linfócitos TRESUMO
BACKGROUND: Fms-like tyrosine kinase 3 (FLT3) expression and mutation have been considered a poor prognostic factor in acute myeloid leukemia (AML). FLT3-ITD mutation is present in 30% of adult patients with AML and 2-5% in childhood acute lymphoblastic leukemia (ALL). The impact of these mutations on the prognosis of ALL patients, has not yet been established. Moreover, a limited number of publications regarding the level of expression of the FLT3 receptor (CD135) in both leukemias exist. This study aimed to analyze the clinical outcomes associated to the presence of FLT3-ITD mutation and the expression of CD135. METHODS: 82 adult patients with newly diagnosed acute leukemia (39 with AML and 43 with ALL) were included. Flow cytometry and RT-PCR were done to analyze the expression of CD135 and the presence of FLT3 ITD mutation, respectively. RESULTS: FLT3-ITD was present in 14 (36%) of AML and 15 (35%) of ALL patients. Disease free survival (DFS) and overall survival (OS) were lower in ALL patients having a CD135 expression >3000 cells/µL. There was a trend for poor OS in AML patients expressing FLT3 ITD. OS was worse in AML patients with high expression of CD135. CONCLUSION: A higher (35%) frequency of FLT3-ITD was found in adult ALL patients. The presence of FLT3-ITD was associated with a trend of poor OS in AML cases, and overexpression of CD135 was correlated with poor DFS in ALL cases and poor OS in both acute leukemias.
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Leucemia Mieloide Aguda/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Tirosina Quinase 3 Semelhante a fms/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Prognóstico , Adulto Jovem , Tirosina Quinase 3 Semelhante a fms/biossíntese , Tirosina Quinase 3 Semelhante a fms/genéticaRESUMO
BACKGROUND: Tumor immunoedition involves alterations in cells of immune system, which may play an important role in the immunosurveillance of patients with cancer diseases. AIM OF THE STUDY: To determine the association between the number of immune cells and the expression of surface markers in leukemic cells of patients with de novo CML who achieved molecular response. METHODS: A longitudinal study was conducted in 31 patients with de novo CML. Peripheral blood samples were obtained at diagnosis for quantification of immune cells and tumor cells expressing CD200, CD135, GpP, and Bcl-2. Results were compared with a group of 60 healthy donors. Lymphocyte subsets were analyzed during a 48 month follow-up period and molecular response to treatment was assessed simultaneously by QT-PCR. The group of patients with deep molecular response was compared with de novo CML patients; the cut-off value of cell count was determined by ROC analysis. Kaplan-Meier and Cox proportional hazard model were used to determine the significant association between the number of cells and progression-free survival. RESULTS: Differences in number of CD4, CD4Tregs, NK, γδT, monocytes, and pDC's, tumor-cells expressing CD200+, CD135+, GpP+, and Bcl-2+ were observed between patients and healthy donors. The number of γδT lymphocytes, CD200+, and CD135+ cells were associated with longer progression-free survival (p = 0.0112, p = 0.0012 and p = 0.0201 respectively). CONCLUSION: A γδT lymphocyte count <63 cel/uL, CD200+ <997 cel/uL, and CD135+ <23 317 cel/uL at diagnosis is associated with the maintenance of deep molecular response at 48 months in patients with de novo CML.
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Antígenos CD/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/imunologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Linfócitos T Reguladores/imunologia , Tirosina Quinase 3 Semelhante a fms/metabolismo , Adulto , Células Dendríticas/imunologia , Feminino , Humanos , Vigilância Imunológica/imunologia , Células Matadoras Naturais/imunologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Estudos Longitudinais , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Intervalo Livre de Progressão , Modelos de Riscos Proporcionais , Receptores de Antígenos de Linfócitos T gama-deltaRESUMO
Multiple myeloma (MM) is a disease characterized by antitumoral immune dysfunction. The objective of the present study was to determine lymphocyte subsets (B, T, NK, NKT, iNKT, dendritic cells, and regulatory T cells) in 68 newly diagnosed patients and 113 healthy donors. Lymphocyte subsets were studied in the same patients 6 months after treatment. Pre-treatment values of CD4+ T cells, NK cells, type 2 dendritic cells, and B cells in MM patients were lower than in healthy donors. Forty patients (59%) received MPT treatment and 28 (41%) thal-dex. Patients with no response to treatment, exhibited a decrease in CD4+ T cells and NK cells, as well as an increase in Treg cell numbers. Median DFS and OS was lower in patients not achieving response, in patients having low numbers of NK cells, and higher values of LDH. The number of CD4 T cells, NK, DC2, and B cells at diagnosis is lower in patients with MM. Non-responder patients had lower CD4 and NK, but higher Treg cell values. Patients in which response is not achieved, and those holding lower values of NK cells and higher levels of LDH, have poor DFS and OS.
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Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Células Matadoras Naturais , Mieloma Múltiplo , Idoso , Dexametasona/administração & dosagem , Intervalo Livre de Doença , Feminino , Humanos , Contagem de Linfócitos , Masculino , Melfalan/administração & dosagem , Pessoa de Meia-Idade , Mieloma Múltiplo/sangue , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/mortalidade , Prednisolona/administração & dosagem , Taxa de Sobrevida , Talidomida/administração & dosagemRESUMO
BACKGROUND: Acute lymphoblastic leukemia is an aggressive malignant disease with high mortality rates in adults. AIM OF THE STUDY: The expression levels of CD95, active caspase-3, and Bcl-2 were determined in 111 patients with de novo acute lymphoblastic leukemia (ALL) and correlated with overall survival (OS) and disease-free survival (DFS). METHODS: The immunophenotyped ok leukemia and the expression of CD95, active caspase-3, and Bcl-2, were determined by flow cytometry. Apoptotic variables were correlated by Spearman test, and survival by Kaplan-Meier method. Log-rank test was used to compare survival curves. RESULTS: From a total of 111 patients, 56 cases were B-ALL, 16 T-ALL, 16 B-ALL/CD33+, and 23 ambiguous lineage-AL (AmbLin-AL). The median expression of CD95 (61.5%) and active-caspase-3 (19.4%) was higher in T-ALL (p <0.05), whereas Bcl-2 was lower in T-ALL (p <0.038). There was a highly significant correlation in B-ALL, B-ALL/CD33+ and AmbLin-AL between CD95 and Bcl-2, CD95-Active caspase-3, and Bcl-2-Active caspase-3; while in T-ALL, there was only a correlation between CD95-Active caspase-3, and Bcl-2-Active caspase-3. OS and DFS were better for T-ALL than the other groups, especially in patients having higher values of CD95 and active caspase 3, and lower values of Bcl-2. The worse survival rates were observed in patients with B-ALL/CD33+, and AmbLin-AL. CONCLUSIONS: The prognosis of ALL in adults is influenced by the expression levels of Bcl-2, active-caspase-3, and CD95.
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Caspase 3/biossíntese , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Receptor fas/biossíntese , Adulto , Apoptose/imunologia , Caspase 2/biossíntese , Cisteína Endopeptidases/biossíntese , Intervalo Livre de Doença , Feminino , Citometria de Fluxo , Humanos , Imunofenotipagem , Masculino , Pessoa de Meia-Idade , Prognóstico , Adulto JovemRESUMO
Receptor tyrosine kinase (RTK) activity may contribute to carcinogenesis. The c-Kit receptor, a member of the RTK family, is expressed in immature haematopoietic system cells. Acute lymphoblastic leukaemia (ALL) presents incompletely differentiated lymphoblasts, and consequently, c-Kit expression can be detected in these cells. The BCR-ABL kinase, which is usually present in both ALL and chronic myeloid leukaemia, can trigger signalling pathways with neoplastic effects. However, a certain number of ALL patients and chronic myeloid leukaemia patients do not express this kinase, raising the question of which other proteins that intervene in signalling pathways may be involved in the development of these diseases. OBJECTIVES: To test whether c-Kit has proliferative effects and affects the inhibition of apoptosis of leukaemic lymphoblasts that do not express BCR-ABL. METHODS: We cultured RS4:11 lymphoblasts and analysed the expression and activation of c-Kit by immunofluorescence, and flow cytometry, evaluation of cell proliferation, apoptosis, cyclin D1 and Bak expression were carried out by flow cytometry; activation of AKT and survivin expression were tested by immunoblot. RESULTS: The c-Kit receptor was found to induce proliferation and to increase the expression of cyclin D1 via the PI3K/AKT/NF-kB signalling pathway. Additionally, the c-Kit/PI3K/AKT pathway increased the inhibition of apoptosis and survivin expression. Similarly, c-Kit was observed to reduce the expression of the pro-apoptotic Bak protein. CONCLUSION: These results suggest that, in leukaemic lymphoblasts, c-Kit triggers a signalling pathway with proliferative and anti-apoptotic effects; information to this effect has not yet been reported in the literature.