Asociación del inmunofenotipo linfocitario de sangre periférica con la presencia de linfomas no Hodgkin / Association of peripheral blood lymphoid immunophenotype with presence of non-Hodgkin lymphomas

Introducción: Los cambios en el inmunofenotipo de los linfocitos en los pacientes con linfoma no Hodgkin están asociados con el pronóstico y las respuestas terapéuticas. Sin embargo, no se ha establecido sistemáticamente la asociación con la enfermedad y por tanto su contribución al diagnóstico. Objetivo: Evaluar la asociación del inmunofenotipo linfocitario en sangre periférica con la presencia del linfoma no Hodgkin. Métodos: Se analizaron 31 muestras de sangre periférica de pacientes con diagnóstico confirmado de linfoma no Hodgkin y de 68 individuos sanos como controles, durante el período de 2018 a 2020. Se empleó la citometría de flujo multiparamétrica para el inmunofenotipado. Se calculó el área bajo la curva y el índice de Youden para establecer puntos de corte en los porcentajes linfocitarios. La asociación de los cambios inmunofenotípicos con el linfoma no Hodgkin, se realizó mediante cálculos de Odd ratio. Resultados: El aumento de linfocitos TCD8+ y NKCD56opaco se asoció significativamente con la presencia de linfoma no Hodgkin (OR= 3,4 y 2,9; respectivamente). Por el contrario, la disminución de linfocitos TCD4+, T doble positivo, T doble negativo y NKCD56brillante también se asoció con la existencia de linfoma no Hodgkin (OR= 23,0; 10,7; 6,9 y 15,8; respectivamente). Además, la disminución del índice CD4/CD8 también fue asociada con la enfermedad. Conclusiones: Los cambios encontrados en los inmunofenotipos linfocitarios se asociaron de forma significativa con la presencia del linfoma no Hodgkin, lo cual representa una expresión sistémica de la enfermedad y sugiere su valor diagnóstico(AU)

Introduction: Lymphocyte immunophenotype changes in non-Hodgkin lymphoma patients are associated with prognosis and therapeutic responses. However, its association with the disease has not been systematically established. Therefor its contribution to the diagnosis process. Objective: To assess the association of lymphocyte immunophenotype in peripheral blood with the presence of non-Hodgkin lymphoma. Methods: 31 peripheral blood samples were analyzed from patients with a confirmed diagnosis of non-Hodgkin lymphoma and from 68 healthy individuals as controls, during the period 2018 to 2020. Multiparametric flow cytometry was used for immunophenotyping. The area under the curve and the Youden index were calculated to establish cut-off points in lymphocyte percentages. The association of immunophenotypic changes with non-Hodgkin's lymphoma was made using Odd ratio calculations. Results: The increase in TCD8+ and NKCD56dim lymphocytes from peripheral blood was significantly associated with the presence of non-Hodgkin lymphoma (OR= 3.4 and 2.9, respectively). Oppositely, the decrease in TCD4+, double positive T, double negative T and NKCD56bright lymphocytes was associated with the existence of non-Hodgkin lymphoma (OR= 23.0, 10.7, 6.9 and 15.8, respectively). Therefore, the decrease in the CD4/CD8 rate was also associated with the disease. Conclusion: The changes found in these lymphocytic immunophenotypes were significantly associated with the presence of non-Hodgkin lymphoma, which represents a systemic expression of the disease and suggests its diagnostic value(AU)

Caracterización de los inmunofenotipos linfocitarios de sangre periférica en pacientes con cáncer / Characterization of peripheral blood lymphocytes immunophenotype in cancer patients

Introducción: La determinación de los inmunofenotipos linfocitarios en sangre periférica forma parte de la evaluación del estado general del sistema inmunitario. Estos exámenes ofrecen informaciones sobre la distribución, concentración y funcionabilidad de las células inmunitarias, lo cual contribuye a establecer pronósticos en el cáncer y predicciones a las respuestas terapéuticas. Objetivo: Evaluar la distribución de las concentraciones linfocitarias circulantes en sangre periférica de pacientes con cáncer. Métodos: Se realizó un estudio analítico en 154 pacientes con cáncer, atendidos en el Instituto de Oncología y Radiobiología de La Habana, durante los años 2017 a 2019. Se empleó la citometría de flujo multiparamétrica para identificar los inmunofenotipos linfocitarios. Este procedimiento se realizó antes de comenzar cualquier tratamiento inmunoterapéutico. Resultados: Los pacientes con cáncer mostraron mayor heterogeneidad en la distribución de las poblaciones linfocitarias respecto a los controles. En los pacientes la mediana de los linfocitos totales y de las subpoblaciones linfocitarias CD3+, CD4+, CD8+ y CD19+ fueron significativamente menores. Los linfocitos T dobles positivos (CD4/CD8) se encontraron elevados significativamente. No se hallaron diferencias entre sexos. La edad se asoció negativamente con las concentraciones de las poblaciones T en tumores sólidos, y con T y B en los linfomas. En el cáncer de próstata se obtuvieron los valores más bajos de poblaciones linfocitarias. Conclusiones: Los pacientes con cáncer tienen menor concentración de linfocitos en sangre periférica que los controles sanos. Las células más afectadas fueron las subpoblaciones T y los linfocitos B. La edad se asoció negativamente con las concentraciones sanguíneas de linfocitos, lo cual pudiera estar en relación con la inmunosenescencia(AU)

Introduction: Determination of lymphocytic immunophenotypes in peripheral blood is part of the evaluation of the general state of the immune system. These tests provide information about the distribution, concentration, and functionality of immune cells, which helps establish prognoses in cancer and predictions of therapeutic responses. Objective: To evaluate the distribution of circulating lymphocyte concentrations in peripheral blood of cancer patients. Methods: An analytical study was carried out with 154 cancer patients treated at the Institute of Oncology and Radiobiology in Havana, from 2017 to 2019. Multiparametric flow cytometry was used to identify lymphocyte immunophenotypes. This procedure was performed before beginning any immunotherapeutic treatment. Results: Cancer patients showed greater heterogeneity in the distribution of lymphocyte populations compared to control patients. The median for total lymphocytes and the lymphocyte subpopulations of CD3+, CD4+, CD8+ and CD19+ were significantly lower in patients. CD4+ CD8+ double-positive T lymphocytes were found to be significantly elevated. No sex differences were found. Age was negatively associated with the concentrations of T-cells populations in solid tumors, and with T- and B-cells populations in lymphomas. In prostate cancer, the lowest values ​​of lymphocyte populations were obtained. Conclusions: Cancer patients have a lower concentration of lymphocytes in peripheral blood than healthy patients in the control group. The most affected ones were the T-cells subpopulations and B lymphocytes. Age was negatively associated with blood levels of lymphocytes, which could be related to immunosenescence(AU)

Aplicaciones de la citometría de flujo en el estudio de los síndromes linfoproliferativos crónicos / Applications of flow cytometry in the study of chronic lymphoproliferative syndromes

Introducción: La citometría de flujo es una técnica de avanzada, objetiva y altamente sensible que permite el análisis y la cuantificación simultánea de múltiples parámetros celulares; es muy utilizada en el estudio de las hemopatías malignas. En los últimos años, ha demostrado ser de gran utilidad en la identificación y la caracterización inmunofenotípica de los síndromes linfoproliferativos crónicos. Estos constituyen un grupo heterogéneo de enfermedades caracterizadas por la expansión monoclonal de células linfoides de aspecto maduro. Objetivos: Analizar los aspectos generales de la aplicación de la técnica de citometría de flujo al estudio y clasificación inmunofenotípica de los síndromes linfoproliferativos crónicos. Métodos: Se realizó una investigación bibliográfica-documental acerca del tema. Se consultaron las bases de datos de SciELO y Pubmed. Análisis y síntesis de la información: Se describen los aspectos técnicos de la citometría de flujo, desde la obtención y procesamiento de las muestras hasta la generación del informe por el citómetro; así como la aplicación de la técnica a la caracterización inmunofenotípica de los síndromes linfoproliferativos crónicos. La citometría de flujo multiparamétrica se ha convertido en uno más de los métodos diagnósticos de este síndrome. Uno de los principales objetivos del estudio inmunofenotípico por citometría de flujo consiste en descartar si esa población de células B es clonal o no. Conclusiones: La citometría de flujo permite el análisis, la interpretación y la clasificación inmunofenotípica de los síndromes linfoproliferativos crónicos. Es una herramienta útil en las que se apoya el diagnóstico y el seguimiento de estos pacientes(AU)

Introduction: Flow cytometry is an advanced, objective and highly sensitive technique that allows simultaneous quantification and analysis of multiple cellular parameters. It is widely used in the study of malignant hemopathies. In recent years, it has proved very useful in the identification and immunophenotypic characterization of chronic lymphoproliferative syndromes. These conditions belong to a heterogeneous group of diseases characterized by monoclonal expansion of mature lymphoid cells. Objectives: To analyze the general aspects of flow cytometry application to the study and immunophenotypic classification of chronic lymphoproliferative syndromes. Methods: A bibliographic-documentary research about the topic was carried out. We consulted the SciELO and Pubmed databases. Information analysis and synthesis: The technical aspects of the flow cytometry are described, from obtaining and processing the samples to the cytometer's generating the report; as well as the technique's application to the immunophenotypic characterization of chronic lymphoproliferative syndromes. Multiparametric flow cytometry has become one of the diagnostic methods for this syndrome. One of the main objectives of the immunophenotypic study by flow cytometry is to rule out whether this population of B cells is clonal or not. Conclusions: Flow cytometry allows the analysis, interpretation and immunophenotypic classification of chronic lymphoproliferative syndromes. It is a useful tool that supports the diagnosis and monitoring of these patients(AU)

Diseño de un panel de citometría de flujo para muestras de sangre, ascitis y tejido ovárico / Design of a multicolored flow cytometry panel for blood, ascites and ovarian tissue samples

Introducción: El cáncer epitelial de ovario (CEO) ocupa el sexto lugar en incidencia y mortalidad a nivel mundial y en Cuba, el quinto en incidencia. Este cáncer es inmunogénicoy sus células malignas crecen en interacción conlas células inmunitarias. Su curso clínico depende del infiltrado inflamatorio acompañante del tumor. La citología e histopatología son los métodos diagnóstico de elección. Sin embargo, la citometría de flujo emerge como una tecnología de mayor sensibilidad, objetividad y rapidez. Objetivo: Diseñar un panel multicolor de citometría de flujo para inmunofenotipar el infiltrado linfocitario de tres tipos de muestras de pacientes con CEO. Métodos: Se realizó un diseño experimental, para la creación y evaluación de un panel multicolor de citometríade flujo, en el laboratorio de Inmunología del Instituto Nacional de Oncología y Radiobiología. El panel se diseñó en sangre de 3 sujetos sanos y se optimizó para sangre periférica en 33 sujetos sanos y, en sangre periférica, ascitis y tejido tumoral ovárico de tres pacientes con CEO. En cada muestra se inmunofenotiparon varias poblaciones linfocitarias. Resultados: Se seleccionaron 11 marcadores antigénicos para el inmunofenotipo, el panel quedó conformado por 4 tubos de citometría. La metodología se pudo aplicar a las muestras de ascitis y tejido tumoral sin interferencias, se obtuvieron porcentajes de las subpoblaciones linfocitarias dentro de los valores esperados. Conclusiones: El panel diseñado permitió inmunofenotipar linfocitos en distintos tipos de muestras de pacientes con CEO, con resultados confiables y reproducibles. Esta metodología puede extenderse a la realización de inmunofenotipaje en otras enfermedades(AU)

Introduction: Epithelial ovarian cancer occupies the 6th place in incidence and mortality in women worldwide. In Cuba, it occupies the 5th place in incidence in females. This cancer is immunogenic and its malignant cells grow in interaction with multiple cells from immune system. Its clinical course depends largely on the type of inflammatory infiltrate accompanying the tumor. Cytology and histopathology are gold standard as diagnostic methods. However, flow cytometry emerges as a technology with greater sensitivity, objectivity and speed. Objective: To design a multicolored flow cytometry panel to immunophenotype the lymphocytic infiltrate of three types of samples for patients with ovarian cancer. Methods: An experimental design was carried out in vitro for the creation and evaluation of a multicolored flow cytometry panel in the Immunology laboratory of the National Institute of Oncology and Radiobiology of Cuba. The panel was designed in the blood of three healthy subjects; then it was optimized for blood in 33 healthy volunteers and blood, ascites and ovarian tumor tissue, from three patients with epithelial ovarian cancer. Several lymphocytes lineages were immunophenotypedin each sample. Results: Eleven markers were selected for the immunophenotype and the panel was made up of four multiparameter cytometry tubes. The methodology created could be applied to the samples of ascites and tumor tissue without interferences and percentages of different lymphocyte subpopulations were obtained within the expected values. Conclusions: The designed panel allowed immunophenotyping of lymphocytes in different types of ovarian cancer patient samples and reliable and reproducible results were obtained. This methodology could be employed for others diseases(AU)

Supervivencia de pacientes con linfoma no-Hodgkin y síntomas neurológicos según inmunofenotipo del líquido cefalorraquídeo / Survival in non-Hodgkin´s lymphoma patients with neurological symptoms according to the cerebrospinal fluid immunophenotype

Introducción: Los linfomas no-Hodgkin pueden infiltrar el sistema nervioso central y producir síntomas neurológicos, lo cual incrementa la mortalidad. El diagnóstico de esta infiltración se puede realizar mediante el estudio del líquido cefalorraquídeo por la técnica de citometría de flujo, con una mayor sensibilidad que la citología convencional. Objetivo: Estimar la supervivencia global de pacientes con Linfoma no-Hodgkin y síntomas neurológicos según el inmunofenotipo celular del líquido cefalorraquídeo. Métodos: Se realizó un estudio analítico y prospectivo en 15 pacientes con diagnóstico confirmado de linfoma no-Hodgkin y síntomas neurológicos, con citología negativa del líquido cefalorraquídeo, tratados en el servicio de oncología del Instituto Nacional de Oncología y Radiobiología, durante los años 2017 y 2018. El inmunofenotipo fue caracterizado mediante citometría de flujo multiparamétrica. Resultados: El 60,0 por ciento de los pacientes fue del sexo femenino y el 53,4 por ciento mayor de 60 años. Hubo una mortalidad del 26,7 por ciento. Se realizaron 17 inmunofenotipos, el 58,9 por ciento fue normal, el 23,4 por ciento reactivo y el 17,7 por ciento sospechoso de malignidad. La supervivencia global fue mayor en pacientes con líquido cefalorraquídeo con inmunofenotipo normal (HR. 0.04). Conclusiones: La citometría de flujo pudo discriminar células sospechosas de malignidad, en pacientes cuyas citologías fueron negativas. La presencia en el líquido cefalorraquídeo de células atípicas, de pleocitosis y de un índice de linfocito-monocito alto se asoció con una supervivencia global menor(AU)

Introduction: When non-Hodgkin lymphomas infiltrate the central nervous system increases mortality. The diagnosis of this infiltration can be made by the study of cerebrospinal fluid using flow cytometry, with a higher sensitivity than conventional cytology. Objective: To estimate the relationship between the cellular immunophenotype of the cerebrospinal fluid and the overall survival of patients with non-Hodgkin lymphoma and neurological symptoms. Methods: An analytical and prospective study was conducted in 15 patients with confirmed diagnosis of non-Hodgkin lymphoma and neurological symptoms, with negative cytology of the cerebrospinal fluid. Patients cared at Oncology Department of the National Institute of Oncology and Radiobiology, during the years 2017-2018. The immunophenotype was characterized by multiparametric flow cytometry. Results: 60.0 percent of the patients was female and 53.4 percent older than 60 years. There was an overall mortality of 26.7 percent 17 immunophenotypes were found, 58.9 percent of them was normal, 23.4 percent reactive and 17.7 percent suspected of malignancy. Overall survival advantage was obtained in patients with cerebrospinal fluid with normal immunophenotype (HR 0.04). Conclusions: Flow cytometry could discriminate cells suspected of malignancy, in patients whose cytologies were negative. The presence in the cerebrospinal fluid of atypical cells, pleocytosis and a high lymphocyte-monocyte index were associated with a lower overall survival(AU)

CD45 y leucemia linfoide aguda pediátrica / CD45 and childhood acute lymphoblastic leukemia

Introducción: El CD45 se expresa en las células hematopoyéticas, su determinación es indispensable para la clasificación inmunofenotípica de la leucemia linfoide aguda (LLA). Objetivo: Evaluar la expresión del antígeno CD45 en los blastos de pacientes pediátricos con LLA y su relación con las características biológicas, morfológicas y clínicas al inicio de la enfermedad, la respuesta al tratamiento y la supervivencia global (SG) de los enfermos. Métodos: Se estudiaron 160 pacientes con LLA entre diciembre del 2012 y diciembre del 2017, tratados con el protocolo ALL-IC BFM-SG 2009. El inmunofenotipaje celular de la médula ósea se realizó por citometría de flujo. Resultados: El fenotipo B CD45+ predominó en los menores de seis años de edad y en los mayores de diez, el fenotipo T CD45+. Se encontró diferencia significativa entre la ausencia de adenopatías mediastínicas, el fenotipo leucémico y la ausencia de CD45 (p=0.004); entre la respuesta a la prednisona en sangre periférica al día ocho, el fenotipo leucémico y la ausencia de CD45 (p=0.001). Se encontraron diferencias significativas entre la respuesta a la prednisona en sangre periférica el día ocho y la respuesta en médula ósea el día 33, según fenotipo leucémico (p=0.009) y la presencia en los blastos del antígeno CD45 (p=0.02). Se encontró diferencia significativa entre la SG de los enfermos, según fenotipo leucémico y la ausencia del antígeno CD45 (p=0.017). Conclusión: La expresión o ausencia del antígeno de CD45 en los blastos tiene relación con la respuesta al tratamiento y la SG de pacientes pediátricos con LLA(AU)

Introduction: CD45 is expressed in hematopoietic cells, its determination is essential for the immunophenotypic classification of acute lymphoid leukemia (ALL). Objective: To evaluate the expression of the CD45 antigen in the blasts of pediatric patients with ALL and its relationship with the biological, morphological and clinical characteristics at the onset of the disease, the response to treatment and the overall survival (OS) of the patients. Methods: 160 patients with ALL were studied between December 2012 and December 2017, treated with the ALL-IC BFM-SG 2009 protocol. Bone marrow cellular immunophenotyping was performed by flow cytometry. Results: Patients with the CD45 + B phenotype predominated in those under six years of age, while those with a CD45 + T phenotype in those older than ten. A significant difference was found between the absence of mediastinal lymph nodes, the leukemic phenotype and the absence of CD45 (p = 0.004). A significant difference was found between the response to prednisone in peripheral blood at day eight, the leukemic phenotype and the absence of CD45, p = 0.001. Significant differences were found between the response to prednisone in peripheral blood on day eight and the response in bone marrow on day 33, according to leukemic phenotype and the presence in blasts of the CD45 antigen (p = 0.009 and p = 0.02, respectively). A significant difference was found between the OS of patients, according to leukemic phenotype and the absence of the CD45 antigen, p = 0.017. Conclusion: The expression or absence of the CD45 antigen in blasts is related to the response to treatment and OS of pediatric patients with ALL(AU)

Leucemia linfoide crónica de células B: revisión de sus aspectos etiopatogénicos, moleculares y pronósticos / B-cell chronic lymphoid leukemia: a review of its etiopathogenic, molecular and prognostic aspects

La leucemia linfoide crónica (LLC) es una neoplasia maligna que afecta principalmente a pacientes de mediana edad y ancianos. Se caracteriza por la proliferación de linfocitos morfológicamente maduros pero inmunoincompetentes que se acumulan en sangre periférica, médula ósea y tejido linfático. Presenta gran heterogeneidad clínica. Se describen diversos fenotipos, aunque predomina la expansión clonal de células B CD5+CD23+. Los factores pronósticos en la LLC incluyen el subgrupo citogenético, estado mutacional de inmunoglobulina, la expresión de ZAP-70, CD38 y CD49d. El tratamiento se basa en usar modernos algoritmos terapéuticos aprobados, que produzcan mayores respuestas y menores eventos secundarios, en lograr la remisión clínica completa y mejorar la calidad de vida de estos pacientes(AU)

Chronic lymphocytic leukemia (CLL) is a malignancy that mainly affects middle-aged and elderly patients. It is characterized by the proliferation of morphologically mature but immunoincompetent lymphocytes that accumulate in blood, bone marrow and lymphatic tissue. It presents great clinical heterogeneity. Several phenotypes are described, although the clonal expansion of CD5 + CD23 + B cells predominates. Prognostic factors include the cytogenetic subgroup, immunoglobulin mutational status, expression of ZAP-70, CD38, and CD49d. The treatment is based on using modern approved therapeutic algorithms that produce greater responses and minor secondary events, to achieve complete clinical remission and to improve the quality of life of these patients(AU)

Reporte de la Primera Reunión Nacional de Consenso para la Inmunofenotipificación de Leucemias Agudas / Report of the First National Consensus Meeting for the Immunophenotyping of Acute Leukemias

Resumen En 2005 se publicaron recomendaciones para la tipificación de hemopatías malignas en Latinoamérica. Se consideró necesario realizar una reunión nacional para actualizarlas. Se convocaron y reunieron 95 profesionales expertos en el tema para analizar y contrastar alternativas y llegar a un consenso. Se alcanzaron opiniones de consenso en lo relativo a indicaciones, tipos y manejo de muestras, anticuerpos, nomenclatura e informe de resultados para el diagnóstico y seguimiento de las leucemias agudas. Las recomendaciones se describen en este artículo y se hace hincapié en la necesidad de que los laboratorios nacionales se apeguen a ellas.

Abstract Recommendations for the typing of hematological malignancies in Latin America were published in 2005. Carrying out a national meeting to update them was deemed necessary. 95 professional experts on the subject were invited in order to analyze and contrast alternatives and reach a consensus. Consensus opinions were reached regarding indications, sample types and processing, antibodies, nomenclature and reporting of results for the diagnosis and monitoring of acute leukemias. This paper describes the recommendations and emphasizes on the need for national laboratories to adhere to them.

Ki-67 expression in mature B-cell neoplasms: a flow cytometry study

SUMMARY OBJECTIVE: Ki-67 is a nuclear protein associated with cellular proliferation in normal or leukemic conditions that can help identify more aggressive diseases and is usually evaluated with immunohistochemistry. The aim of this was to assess Ki-67 expression on mature B-cell neoplasms samples with flow cytometry immunophenotyping. METHOD: After surface staining with CD19 and CD45, intracellular staining for Ki-67 was performed in leukemic mature B-cells. Ki-67 expression was evaluated with flow cytometry. RESULTS: Ki-67 expression was higher in mantle cell lymphoma, Burkitt lymphoma, and diffuse large B-cell lymphoma cases. It was also associated with CD38 mean fluorescence intensity. CONCLUSIONS: Ki-67 expression evaluated by flow cytometry can be a useful tool in the diagnosis of mature B-cell neoplasms. More studies are needed to validate Ki-67 assessment with flow cytometry immunophenotyping.

RESUMO OBJETIVO: Ki-67 é uma proteína nuclear associada à proliferação celular em condições normais ou leucêmicas que pode ajudar a Identificar doenças mais agressivas. Este marcador é geralmente avaliado com imuno-histoquímica. O objetivo deste estudo foi avaliar a expressão de Ki-67 em amostras de neoplasias de células B maduras com imunofenotipagem por citometria de fluxo. MÉTODO: Após marcação de superfície com CD19 e CD45, foi realizada marcação intracelular para Ki-67 em células B maduras leucémicas. A expressão de Ki-67 foi avaliada por citometria de fluxo. RESULTADOS: A expressão de Ki-67 foi maior em células de linfomas de manto, linfoma de Burkitt e linfoma difuso de grandes células B. Também houve associação de Ki-67 à intensidade de fluorescência média de CD38. CONCLUSÃO: A expressão de Ki-67 avaliada por citometria de fluxo pode ser útil no diagnóstico de neoplasias de células B maduras. São necessários mais estudos para validar a avaliação de Ki-67 com Imunofenotipagem por citometria de fluxo.

Aspectos generales de algunas entidades dentro de los síndromes linfoproliferativos crónicos: La leucemia linfoide crónica / General aspects of some entities within chronic lymphoproliferative syndromes: chronic lymphocytic leukemia

La leucemia linfoide crónica es el tipo de leucemia más común en los países occidentales, afecta con mayor frecuencia al sexo masculino, con una edad promedio al diagnóstico de 65 años. La variedad más frecuente es la de estirpe B; comprenden un grupo de neoplasias biológicamente diferentes, caracterizadas por una proliferación y acúmulo de linfocitos pequeños de apariencia madura en sangre periférica, médula ósea y tejidos linfoides. Es el prototipo de enfermedad maligna que involucra a defectos de la muerte celular programada o apoptosis. Esta enfermedad puede presentar variaciones en sus características inmunofenotípicas, clínicas, citogenéticas y moleculares. Aproximadamente, el 80 por ciento de los pacientes con leucemia linfoide crónica B presentan anormalidades cromosómicas, principalmente: deleciones de los cromosomas 11,13, 6,14 y 17, estas tres últimas de mal pronóstico. Pueden presentar además, disfunciones inmunes responsables de inmunodeficiencia y autoinmunidad. Se desconoce la causa de esta enfermedad aunque los informes iniciales sugieren la implicación de los genes Bcl-1 y Bcl-2, es por eso que la terapia actual está dirigida a la inhibición de Bcl-2 por ser el responsable en la regulación de la apoptosis(AU)

Chronic lymphoid leukemia is the most common type of leukemia in Western countries, which most often affects males and the average age at diagnosis is 65 years. The most common form is the B-cell and is described in this article. LLC comprise a biologically distinct group of neoplasms characterized by proliferation and accumulation of small mature lymphocytes appearance in peripheral blood, bone marrow and tissues linfoides. Is the prototype of malignant disease involving defects programmed cell death or apoptosis. This disease may present variations in their immunophenotypic, clinical, cytogenetic and molecular characteristics. Approximately 80 percent of patients with B-CLL have chromosomal abnormalities, mainly: deletions of chromosomes 11, 13, 6, 14 and 17. These last three are bad prognosis. The patients with CLL may have also immune dysfunctions responsible for immunodeficiency and autoimmunity. It is unknown the cause of CLL although initial reports suggest the involvement of Bcl-1 and Bcl-2 gene is why the current therapy is directed to inhibition of Bcl-2 as this is responsible in regulating apoptosis(AU)

Cut-off value for absolute lymphocytes as an alternative for the immunophenotypic analysis of CD3+ T cells in the monitoring of immunosuppressive therapy with thymoglobulin / Valor de corte para linfócitos absolutos como alternativa para análise imunofenotípica de células T CD3+ no monitoramento de terapia imunossupressora com timoglobulina

Abstract Introduction: Immunosuppression of T lymphocytes is required for preventing acute rejection after transplantation and for the treatment of chronic autoimmune and inflammatory diseases. The laboratory monitoring for this therapy is the measurement of T cells by immunophenotyping, aiming the target value of less than 20 cells per µL. Objective: To establish a cut-off point for the total number of lymphocytes in the automated blood cell count that reflects less than twenty T cells µL by immunophenotyping. Methods: We studied and evaluated 242 kidney transplant patients that had results of automated blood cell count and quantification of T cells by immunophenotyping technique. The patients were divided into two groups, depending on the T lymphocyte immunophenotyping rates established by lower and higher than 20 cells per µL. After, we evaluated the cut-off point for lymphocytes in the blood cell count with a specificity of 100% to exclude patients with high levels of T lymphocytes. Results: We found that the cut-off point of 70 lymphocytes per µL obtained by automated blood cell count showed 100% of specificity to exclude patients with T-cell counts higher than 20 cells per µL by immunophenotyping. Conclusion: The results found in this study may be helpful to monitor the immunosuppressive therapy in kidney transplant patients in places where a flow cytometer is not available, or when this equipment is not present in the full routine.

Resumo Introdução: A imunossupressão de linfócitos T é necessária para a prevenção da rejeição aguda em transplantes e no tratamento de doenças autoimunes e inflamatórias crônicas. O seu monitoramento laboratorial consiste na quantificação dos linfócitos T realizada pela técnica de imunofenotipagem, na qual o valor preconizado é manter inferior a 20 células/µL. Objetivo: Estabelecer um ponto de corte para o número de linfócitos totais no hemograma automatizado que reflita uma contagem de linfócitos T inferior a 20 células/µL por imunofenotipagem. Métodos: Foram avaliados 242 pacientes transplantados renais que continham resultados do hemograma automatizado e quantificação de linfócitos T por imunofenotipagem. Os pacientes foram divididos em dois grupos, conforme os valores de linfócitos T estabelecidos pela imunofenotipagem: inferiores e superiores a 20 células/µL. A partir disto, foi avaliado o ponto de corte de linfócitos no hemograma com especificidade de 100% para excluir os pacientes com valores elevados de linfócitos T. Resultados: Este estudo evidenciou que o ponto de corte de 70 linfócitos/µL obtidos pelo hemograma automatizado apresentou especificidade de 100% para excluir os pacientes com contagens de linfócitos T superiores a 20 células/µL na imunofenotipagem. Conclusão: Esta pesquisa poderá auxiliar no monitoramento da terapia imunossupressora em pacientes transplantados renais em locais que não possuem um citômetro de fluxo disponível, ou ainda quando este equipamento não se faz presente na rotina integral.

Novel identification and characterisation of Transient receptor potential melastatin 3 ion channels on Natural Killer cells and B lymphocytes: effects on cell signalling in Chronic fatigue syndrome/Myalgic encephalomyelitis patients

BACKGROUND: Transient receptor potential melastatin 3 (TRPM3) cation channels are ubiquitously expressed by multiple cells and have an important regulatory role in calcium-dependent cell signalling to help maintain cellular homeostasis. TRPM3 protein expression has yet to be determined on Natural Killer (NK) cells and B lymphocytes. Multiple single nucleotide polymorphisms have been reported in TRPM3 genes from isolated peripheral blood mononuclear cells, NK and B cells in Chronic fatigue syndrome/Myalgic encephalomyelitis (CFS/ME) patients and have been proposed to correlate with illness presentation. The object of the study was to assess TRPM3 surface expression on NK and B lymphocytes from healthy controls, followed by a comparative investigation examining TRPM3 surface expression, and cytoplasmic and mitochondrial calcium influx in CD19+ B cells, CD56bnght and CD56dim cell populations from CFS/ME patients. RESULTS: TRPM3 cell surface expression was identified for NK and B lymphocytes in healthy controls (CD56bright TRPM3 35.72 % ± 7.37; CD56dim 5.74 % ± 2.00; B lymphocytes 2.05 % ± 0.19, respectively). There was a significant reduction of TRPM3 surface expression on CD19+ B cells (1.56 ± 0.191) and CD56bright NK cells (17.37 % ± 5.34) in CFS/ME compared with healthy controls. Anti-CD21 and anti-IgM conjugated biotin was cross-linked with streptavidin,and subsequently treatment with thapsigargin. This showed a significant reduction in cytoplasmic calcium ion concentration in CD19+ B lymphocytes. CD56bright NK cells also had a significant decrease in cytoplasmic calcium in the presence of 2-APB and thapsigargin in CFS/ME patients. CONCLUSIONS: The results from this preliminary investigation identify, for the first time, TRPM3 surface expression on both NK and B lymphocytes in healthy controls. We also report for the first time, significant reduction in TRPM3 cell surface expression in NK and B lymphocytes, as well as decreased intracellular calcium within specific conditions in CFS/ME patients. This warrants further examination of these pathways to elucidate whether TRPM3 and impaired calcium mobilisation has a role in CFS/ME.

Metodología y aplicaciones de la citometría de flujo para el inmunofenotipaje de las leucemias agudas / Methodology and applications of flow cytometry for immunophenotyping of acute leukemias

La citometría de flujo (CMF) es una técnica de avanzada, altamente sensible y automatizada, que se emplea para el inmunofenotipaje de las células normales y leucémicas. En este artículo se muestran los principales aspectos metodológicos a tener en cuenta para un mejor desarrollo e interpretación del inmunofenotipo por CMF, entre los que se encuentran: tipo, cantidad, conservación y transportación de la muestra, uso de anticoagulantes, empleo de anticuerpos monoclonales y fluorocromos, lisado de hematíes, fijación celular, así como la calibración y compensación de la auto-fluorescencia. Finalmente, se exponen las principales aplicaciones de esta metodología para definir el estado de maduración celular leucémico, clasificar las leucemias agudas en distintos subtipos inmunológicos, identificar subgrupos de mal pronóstico y detectar fenotipos aberrantes. Todo lo anterior resulta de gran utilidad para el diagnóstico de la enfermedad mínima residual que permite estratificar a los pacientes en diferentes grupos de riesgo e individualizar el tratamiento antileucémico(AU)

Flow cytometry (FCM) is an advanced, highly sensitive and automated technique used for immunophenotyping of normal and leukemic cells. The main methodological aspects to consider for better development and interpretation of immunophenotyping by FCM are shown in this article. Among them are: type, quantity, storage and transportation of the sample, use of anticoagulants, use of monoclonal antibodies and fluorochromes, erythrocyte lysate, cell attachment, calibration and auto-fluorescence compensation. Finally, the main applications of this methodology are given for defining the state of leukemic cell maturation, acute leukemias rank in different immunological subtypes, poor prognosis subgroups and to identify and detect aberrant phenotypes, which are useful for the diagnosis of minimal residual disease, allowing to stratify patients into different risk groups and thus to identify the anti-leukemic treatment(AU)

Perfil imunofenotípico e nível de citocinas plásmáticas em portadores de hepatite C crônica (genótipo 1) com diferentes graus de comprometimento hepático / Immunophenotypic profile and level of plasmatic cytokines in patients with chronic hepatitis C with varying degrees of hepatic impairment

O vírus da hepatite C crônica (VHC) é causa de doença hepática crônica afetando cerca de 3% da população mundial, aproximadamente 170 milhões de pessoas. Investigações sobre a resposta imune em indivíduos infectados com HCV é justificável pelo fato desta constituir doença infecciosa cujas alterações imunológicas têm relação direta com o desenvolvimento e a manutenção da infecção. Este projeto visou avaliar aspectos que compõem a resposta imune de pacientes com hepatite C crônica com diferentes graus de lesão hepática. Foram incluídos no estudo pacientes VHC+ (n=83), genótipo 1, pré-tratamento, os quais foram estratificados conforme o grau de fibrose hepática determinada por biópsia (classificação METAVIR), compondo: G1 (n = 15) pacientes nos estágios F0 (nenhuma fibrose) + F1 (fibrose em expansão dos espaços porta); G2 (n = 21) pacientes no estágio F2 (poucas fontes de fibrose nos espaços porta); G3 (n = 15) pacientes em estágio F3 (início da formação de nódulos); G4 (n = 32) pacientes em estágio F4 (fibrose severa); G5 (n = 16) doadores de sangue voluntários (grupo controle). Foram avaliadas características imunofenotípicas de subpopulações de leucócitos do sangue periférico (células NK totais, NKdim, NKbright, células dendríticas mielóides e plasmocitóides, monócitos clássicos e pro-inflamatórios, linfócitos T CD4+/CD8+), níveis de citocinas e quimiocinas plasmáticas (TGF-β, TNF-α, CCL2, CCL3, CCL4, CCL5, CXCL8, CXCL9, CXCL10), analisando a relação destes com a progressão da fibrose. Todas as frequências das subpopulações leucocitárias avaliadas estão alteradas em portadores de hepatite C crônica comparados com indivíduos saudáveis. Além disso, há correlação entre o grau de fibrose e a quantidade de linfócitos T CD4, T CD8, monócitos pro-inflamatórios e células NKbright circulantes...

The chronic hepatitis C virus (HCV) is the cause of chronic liver disease affecting about 3% of world population, approximately 170 million people. Investigations of the immune response in individuals infected with HCV is justifiable because this form infectious disease whose immunological changes are directly related to the development and maintenance of infection. This project aimed to evaluate aspects that make up the immune chronic hepatitis C patients with different degrees of liver damage response. The study included patients HCV+ (n = 83), genotype 1, pretreatment, which were classified according to the rate of hepatic fibrosis determined by biopsy (METAVIR classification), composed of: G1 (n = 15) patients in stages F0 (no fibrosis) + F1 (fibrosis expansion of port spaces), G2 (n = 21) patients in the F2 stage (few sources of fibrosis in portal ), G3 ( n = 15 ) patients with stage F3 (early nodule formation), G4 (n = 32) patients with stage F4 (severe fibrosis), G5 (n = 16) volunteer blood donors (control group). Immunophenotypic characteristics of subpopulations of peripheral blood leukocytes (total NK cells, NKdim , NKbright , myeloid dendritic cells and plasmacytoid , classical monocytes, pro- inflammatory CD4 + / CD8 + cells), cytokine levels and plasma chemokines (were evaluated TGF- β , TNF - α , CCL2 , CCL3 , CCL4 , CCL5 , CXCL8 , CXCL9, CXCL10), analyzing their relationship with the progression of fibrosis. All frequencies of evaluated leukocyte subpopulations are altered in patients with chronic hepatitis C compared with healthy subjects. In addition, no correlation between the degree of fibrosis and the amount of CD4, CD8, pro-inflammatory monocytes and circulating NKbright cells. Increased levels of TNF-α were observed in cirrhotic patients (G4) and TGF - β in HCV + groups with moderate hepatic fibrosis (G2 and G3)...

Perfil imunofenotípico e nível de citocinas plásmáticas em portadores de hepatite C crônica (genótipo 1) com diferentes graus de comprometimento hepático / Immunophenotypic profile and level of plasmatic cytokines in patients with chronic hepatitis C with varying degrees of hepatic impairment

O vírus da hepatite C crônica (VHC) é causa de doença hepática crônica afetando cerca de 3% da população mundial, aproximadamente 170 milhões de pessoas. Investigações sobre a resposta imune em indivíduos infectados com HCV é justificável pelo fato desta constituir doença infecciosa cujas alterações imunológicas têm relação direta com o desenvolvimento e a manutenção da infecção. Este projeto visou avaliar aspectos que compõem a resposta imune de pacientes com hepatite C crônica com diferentes graus de lesão hepática. Foram incluídos no estudo pacientes VHC+ (n=83), genótipo 1, pré-tratamento, os quais foram estratificados conforme o grau de fibrose hepática determinada por biópsia (classificação METAVIR), compondo: G1 (n = 15) pacientes nos estágios F0 (nenhuma fibrose) + F1 (fibrose em expansão dos espaços porta); G2 (n = 21) pacientes no estágio F2 (poucas fontes de fibrose nos espaços porta); G3 (n = 15) pacientes em estágio F3 (início da formação de nódulos); G4 (n = 32) pacientes em estágio F4 (fibrose severa); G5 (n = 16) doadores de sangue voluntários (grupo controle). Foram avaliadas características imunofenotípicas de subpopulações de leucócitos do sangue periférico (células NK totais, NKdim, NKbright, células dendríticas mielóides e plasmocitóides, monócitos clássicos e pro-inflamatórios, linfócitos T CD4+/CD8+), níveis de citocinas e quimiocinas plasmáticas (TGF-β, TNF-α, CCL2, CCL3, CCL4, CCL5, CXCL8, CXCL9, CXCL10), analisando a relação destes com a progressão da fibrose. Todas as frequências das subpopulações leucocitárias avaliadas estão alteradas em portadores de hepatite C crônica comparados com indivíduos saudáveis. Além disso, há correlação entre o grau de fibrose e a quantidade de linfócitos T CD4, T CD8, monócitos pro-inflamatórios e células NKbright circulantes...

The chronic hepatitis C virus (HCV) is the cause of chronic liver disease affecting about 3% of world population, approximately 170 million people. Investigations of the immune response in individuals infected with HCV is justifiable because this form infectious disease whose immunological changes are directly related to the development and maintenance of infection. This project aimed to evaluate aspects that make up the immune chronic hepatitis C patients with different degrees of liver damage response. The study included patients HCV+ (n = 83), genotype 1, pretreatment, which were classified according to the rate of hepatic fibrosis determined by biopsy (METAVIR classification), composed of: G1 (n = 15) patients in stages F0 (no fibrosis) + F1 (fibrosis expansion of port spaces), G2 (n = 21) patients in the F2 stage (few sources of fibrosis in portal ), G3 ( n = 15 ) patients with stage F3 (early nodule formation), G4 (n = 32) patients with stage F4 (severe fibrosis), G5 (n = 16) volunteer blood donors (control group). Immunophenotypic characteristics of subpopulations of peripheral blood leukocytes (total NK cells, NKdim , NKbright , myeloid dendritic cells and plasmacytoid , classical monocytes, pro- inflammatory CD4 + / CD8 + cells), cytokine levels and plasma chemokines (were evaluated TGF- β , TNF - α , CCL2 , CCL3 , CCL4 , CCL5 , CXCL8 , CXCL9, CXCL10), analyzing their relationship with the progression of fibrosis. All frequencies of evaluated leukocyte subpopulations are altered in patients with chronic hepatitis C compared with healthy subjects. In addition, no correlation between the degree of fibrosis and the amount of CD4, CD8, pro-inflammatory monocytes and circulating NKbright cells. Increased levels of TNF-α were observed in cirrhotic patients (G4) and TGF - β in HCV + groups with moderate hepatic fibrosis (G2 and G3)...

Inmunofenotipos aberrantes en leucemias agudas en una población hospitalaria de Buenos Aires / Aberrant immunophenotypes in acute leukemia in a Buenos Aires' hospital population

La citometría de flujo multiparamétrica es el método de elección para la caracterización inmunofenotípica de las células hematopoyéticas clonales presentes en los distintos procesos leucémicos agudos. El objetivo fue analizar la expresión de antígenos de membrana y evaluar la presencia de fenotipos aberrantes en los blastos de pacientes con diagnóstico de leucemia aguda, que permiten el monitoreo de la respuesta al tratamiento. Se revisaron los inmunofenotipos de 364 muestras de pacientes adultos derivadas a nuestro laboratorio en un período de 7 años. El inmunofenotipo se realizó por citometría de flujo con un amplio panel de anticuerpos monoclonales con el que se evaluó la expresión de antígenos de linaje linfoide, mieloide y también antígenos de maduración. De las 364 muestras estudiadas, 60.2% presentaron un fenotipo compatible con leucemia mieloide aguda (LMA), 28.8% con leucemia linfoblástica B (LLA-B), 6.6% con leucemia linfoblástica T (LLA-T) y 4.4% con leucemias agudas poco frecuentes. La presencia de fenotipos aberrantes se observó en 89% de los casos, los fenotipos aberrantes identificados fueron: 1) infidelidad de linaje: LMA (54%), LLA-B (40%), LLA-T (29%); 2) ausencia de expresión antigénica: LMA (21%), LLA-B (35%), LLA-T (70%); 3) alteración de la expresión antigénica: LMA (67%), LLA-B (66%), LLA-T (84%); 4) asincronismo madurativo: LMA (26%), LLA-B (37%) y 5) fenotipo ectópico: LLA-T 96%). El análisis por citometría de flujo multiparamétrica de las leucemias agudas permitió la identificación de fenotipos aberrantes en la mayoría de nuestros pacientes, que son de utilidad para el monitoreo de la respuesta al tratamiento.

Multiparameter flow cytometry (MFC) has become the preferred method for the lineage assignment and maturational analysis of malignant cells in acute leukemias. Multiparametric immunophenotyping analysis allows the detection of aberrant antigen expression and the analysis of heterogeneity and clonality of malignant cells in leukemias. Our objectives were to analyze the membrane antigen expression and to evaluate if the aberrant phenotypes occurrence in blasts cells of patients with acute leukemia is useful in monitoring the response to the treatment. We have retrospectively analyzed the MFC data of 364 samples sent to our laboratory in a 7 years period. For this purpose we have used a large panel of monoclonal antibodies against lymphoid, myeloid and precursors antigens. From the 364 analyzed samples, 60.2% showe d a phenotype compatible with acute myeloid leukemia (AML), 28.8% with B lymphoblastic leukemia (B-LLA), 6.6% with T lymphoblastic leukemia (T-LLA) and 4.4% with rare leukemias. Aberrant phenotypes were found in 86% of the samples. The aberrant phenotypes identified were:1) lineage infidelity AML (54%), B-ALL (40%), T-ALL (29%); 2) absence of antigen expression: AML (21%), B-ALL (35%), T-ALL (70%); 3) altered antigen expression: AML (67%), B-ALL (66%),T-ALL (84%); 4) asynchronous expression: AML (26%), B-ALL (37%) and 5) ectopic phenotype: T-ALL (96%). Multiparameter flow cytometry of acute leukemias allowed identification of aberrant phenotypes in the majority of our patients, that are helpful for monitoring treatment response.

Efeitos de diferentes pressões de aspiração do tecido adiposo na obtenção de células-tronco mesenquimais / Effects of different liposuction techniques on the isolation of mesenchymal stem cells", "_e": "n

INTRODUÇÃO: O enxerto de gordura nos últimos anos voltou a ter destaque como aliado dos cirurgiões plásticos no preenchimento de partes moles, no rejuvenescimento facial volumétrico, nos refinamentos de reconstruções mamárias e por ser rica fonte de células-tronco de comportamento mesenquimal (células-tronco adipoderivadas). Considerando que essas células têm importante papel na angiogênese e na diferenciação adipogênica, com impacto direto na sobrevivência dos enxertos de gordura, determinar parâmetros que otimizem a sua obtenção é imperativo. Nesse contexto, o objetivo deste trabalho é avaliar e comparar dois métodos de obtenção do tecido adiposo da região abdominal quanto ao número de células viáveis presentes na fração vásculo-estromal e analisar a expressão de marcadores de superfície. MÉTODO: Foram selecionadas 9 pacientes do sexo feminino submetidas a lipoaspiração. O tecido adiposo foi obtido da região abdominal infraumbilical. Da metade direita foram coletados 20 ml de gordura, empregando-se cânula acoplada a uma seringa, cujo êmbolo foi tracionado de 2 cc em 2 cc, gerando baixas pressões de aspiração (grupo manual). O mesmo processo foi repetido na metade esquerda, entretanto a cânula estava acoplada a um coletor intermediário estéril e esse a uma máquina de vácuo sob pressão negativa constante de 350 mmHg (grupo a vácuo). As amostras foram centrifugadas e a gordura da camada intermediária dos dois grupos foi submetida a contagem celular, estabelecimento de culturas e posterior imunofenotipagem. RESULTADOS: Este estudo demonstrou que, apesar de não haver diferença estatisticamente significativa, a obtenção da gordura da região abdominal empregando-se lipoaspirador com pressão negativa de 350 mmHg proporcionou maior número de células presentes na fração vásculo-estromal quando comparado à obtenção por meio de seringas de 10 ml, com baixas pressões de aspiração. CONCLUSÕES: O emprego de pressão negativa de 350 mmHg é seguro para a obtenção das células-tronco adipoderivadas e o rendimento celular entre os dois grupos não apresentou diferença estatisticamente significativa.

BACKGROUND: In recent years, fat grafts have become useful in plastic surgery. They are mainly used to fill soft tissues, refine breast reconstructions, and for volumetric facial rejuvenation. They are also a rich source of mesenchymal stem cells (i.e., adipose-derived stem cells [ADSCs]), which directly influence fat graft survival. Since ADSCs play an important role in angiogenesis and adipogenic differentiation, it is essential to optimize their isolation. Therefore, in this study, we evaluated and compared 2 procedures used to isolate viable cells from the stromal vascular fraction of abdominal adipose tissue and assess the expressions of surface markers. METHODS: We examined 9 female subjects who were scheduled to undergo liposuction. The adipose tissue was isolated from the abdominal infraumbilical region. Fat (20 mL) was collected from the right side by using a cannula attached to a syringe; the plunger was pulled back every 2 cm³ to create low-pressure suction (manual group). The same procedure was repeated on the left side, but the cannula was attached to a sterile and intermediate collector coupled to a vacuum pump that provided a constant negative pressure of 350 mmHg (pump group). The samples were centrifuged, and the adipocytes of the intermediate layer were counted, cultured, and immunophenotyped. RESULTS: The isolation of abdominal adipocytes with a pump providing a negative pressure of 350 mmHg yielded a higher concentration of cells in the stromal vascular fraction than that obtained using 10-mL syringes and low-pressure suction, although the difference was not significant. CONCLUSIONS: A negative pressure of 350 mmHg may be safely applied to isolate ADSCs. The cell yield did not indicate any statistically significant difference between the techniques.

Phenotypic and genotypic characteristics of drug resistance in Mycobacterium tuberculosis isolates from pediatric population of Chennai, India.

Purpose: Multidrug-resistant TB (MDR-TB) has been reported in almost all parts of the world. Childhood TB is accorded low priority by national TB control programs. Probable reasons include diagnostic difficulties, limited resources, misplaced faith in BCG and lack of data on treatment. Good data on the burden of all forms of TB among children in India are not available. Objective: To study the drug sensitivity pattern of tuberculosis in children aged from 3 months to 18 years and the outcome of drug-resistant tuberculosis by BACTEC culture system and PCR-based DNA sequencing technique. Materials and Methods: This is a retrospective study. One hundred and fifty-nine clinical specimens were processed for Ziehl-Neelsen stain, Mycobacterial culture by BACTEC method, phenotypic DST for first-line drugs for Mycobacterium tuberculosis (M. tuberculosis) isolates and PCR-based DNA sequencing was performed for the M. tuberculosis isolates targeting rpoB, katG, inhA, oxyR-ahpC, rpsL, rrs and pncA. Results and Conclusion: Out of the 159 Mycobacterial cultures performed during the study period, 17 clinical specimens (10.7%) were culture positive for M. tuberculosis. Among the 17 M. tuberculosis isolates, 2 were multidrug-resistant TB. PCR-based DNA sequencing revealed the presence of many novel mutations targeting katG, inhA, oxyR-ahpC and pncA and the most commonly reported mutation Ser531Leu in the rpoB gene. This study underlines the urgent need to take efforts to develop methods for rapid detection and drug susceptibility of tubercle bacilli in the pediatric population.