Updating recommendations of the Brazilian Group of Flow Cytometry (GBCFLUX) for diagnosis of acute leukemias using four-color flow cytometry panels

ABSTRACT Introduction: Flow cytometry has become an increasingly important tool in the clinical laboratory for the diagnosis and monitoring of many hematopoietic neoplasms. This method is ideal for immunophenotypic identification of cellular subpopulations in complex samples, such as bone marrow and peripheral blood. In general, 4-color panels appear to be adequate, depending on the assay. In acute leukemias (ALs), it is necessary identify and characterize the population of abnormal cells in order to recognize the compromised lineage and classify leukemia according to the WHO criteria. Although the use of eightto ten-color immunophenotyping panels is wellestablished, many laboratories do not have access to this technology. Objective and Method: In 2015, the Brazilian Group of Flow Cytometry (Grupo Brasileiro de Citometria de Fluxo, GBCFLUX) proposed antibody panels designed to allow the precise diagnosis and characterization of AL within available resources. As many Brazilian flow cytometry laboratories use four-color immunophenotyping, the GBCFLUX has updated that document, according to current leukemia knowledge and after a forum of discussion and validation of antibody panels. Results: Recommendations for morphological analysis of bone marrow smears and performing screening panel for lineage (s) identification of AL were maintained from the previous publication. The lineage-oriented proposed panels for B and T cell acute lymphoblastic leukemia (ALL) and for acute myeloid leukemia (AML) were constructed for an appropriate leukemia classification. Conclusion: Three levels of recommendations (i.e., mandatory, recommended, and optional) were established to enable an accurate diagnosis with some flexibility, considering local laboratory resources and patient-specific needs.

Follow-up and outcome of the twelve-year experience in adult patients with acute promyelocytic leukemia

ABSTRACT Acute promyelocytic leukemia is a subtype of acute myeloid leukemia, characterized by the presence of neoplastic promyelocytes, due to the reciprocal balanced translocation between chromosomes 15 and 17. Currently, with the use of agents that act directly on this molecular change, such as all-trans retinoic acid and arsenic trioxide, APL has shifted from a highly mortal to a curable disease. However, some cases are still at high risk of death, especially early death, and acquiring a better understanding of the clinical and biological factors involving APL is needed to correctly identify and treat such cases. The early suspected diagnosis and prompt initiation of the target therapy are important for better response rates. The follow-up and outcomes, using real-life data from 44 consecutive APL patients, were studied between 2001 and 2013. The overall survival rate was 82.7% and early death was 16%. Almost all patient deaths were due to severe bleeding, which was confirmed by multivariate analysis, as the most important prognostic factor leading to death. A better understanding the pathogenesis of the hemorrhagic complications in APL is needed, as well as the risk factors associated with early death in APL patients, as this has become synonymous with overall mortality.

Analysis of the presence of FLT3 gene mutation and association with prognostic factors in adult and pediatric acute leukemia patients

ABSTRACT When the FLT3 gene is mutated, it originates a modified receptor with structural changes, which give survival advantage and malignant hematopoietic cell proliferation. Thus, the presence of mutations in this gene is considered an unfavorable prognostic factor. A total of 85 consecutive samples of newly diagnosed untreated patients with AL were included in the study after they provided their informed consent. FLT3 gene mutations were detected by PCR. For the pediatric group, a positive correlation was observed between WBC count and the presence of FLT3-ITD in patients with AML and ALL. Furthermore, children with AML who had the FLT3-ITD mutation showed a tendency to express CD34 in blast cells. In the adult group, the AML patients with FLT3-ITD who expressed CD34 in blast cells had a tendency to worse progression. The present data indicate no association between the prognostic factors evaluated and FLT3 gene mutations in adult with AL. Yet, the presence of FLT3-ITD mutation was significantly related with WBC count in the pediatric group. These findings demonstrate that FLT3 gene mutations can be considered as independent poor prognostic factors.

Mature B cell neoplasms: retrospective analysis of 93 cases diagnosed between 2011 and 2014 in a University hospital in southern Brazil

BACKGROUND: According to the 2008 World Health Organization classification, mature B-cell neoplasms are a heterogeneous group of diseases that include B-cell lymphomas and plasma cell disorders. These neoplasms can have very different clinical behaviors, from highly aggressive to indolent, and therefore require diverse treatment strategies. OBJECTIVE: The aim of this study was to assess the profile of 93 patients diagnosed with mature B-cell neoplasms monitored between 2011 and 2014. METHODS: A review of patients' charts was performed and laboratory results were obtained using the online system of the Universidade Federal de Santa Catarina. RESULTS: The study included 93 adult patients with mature B-cell neoplasms. The most frequent subtypes were multiple myeloma, chronic lymphocytic leukemia, diffuse large B-cell lymphoma, follicular lymphoma, and Burkitt's lymphoma. The median age at diagnosis was 58 years with a male-to-female ratio of 1.3:1. There were statistical differences in terms of age at diagnosis, lactate dehydrogenase activity and Ki-67 expression among the subtypes of B-cell lymphoma. According to the prognostic indexes, the majority of multiple myeloma patients were categorized as high risk, while the majority of chronic lymphocytic leukemia patients were classified as low risk. CONCLUSIONS: This study demonstrates the profile of patients diagnosed with mature B-cell neoplasms in a south Brazilian university hospital. Of the B-cell lymphoma, Burkitt's lymphoma presented particular features regarding lactate dehydrogenase activity levels, Ki-67 expression, age at diagnosis, and human immunodeficiency virus infection.

Molecular approach to diagnose BCR/ABL negative chronic myeloproliferative neoplasms

Chronic myeloproliferative neoplasms arise from clonal proliferation of hematopoietic stem cells. According to the World Health Organization myeloproliferative neoplasms are classified as: chronic myelogenous leukemia, polycythemia vera, essential thrombocythemia, primary myelofibrosis, chronic neutrophilic leukemia, chronic eosinophilic leukemia, hypereosinophilic syndrome, mast cell disease, and unclassifiable myeloproliferative neoplasms. In the revised 2008 WHO diagnostic criteria for myeloproliferative neoplasms, mutation screening for JAK2V617F is considered a major criterion for polycythemia vera diagnosis and also for essential thrombocythemia and primary myelofibrosis, the presence of this mutation represents a clonal marker. There are currently two hypotheses explaining the role of the JAK2V617F mutation in chronic myeloproliferative neoplasms. According to these theories, the mutation plays either a primary or secondary role in disease development. The discovery of the JAK2V617F mutation has been essential in understanding the genetic basis of chronic myeloproliferative neoplasms, providing some idea on how a single mutation can result in three different chronic myeloproliferative neoplasm phenotypes. But there are still some issues to be clarified. Thus, studies are still needed to determine specific molecular markers for each subtype of chronic myeloproliferative neoplasm.

Síndromes mielodisplásicas: aspectos moleculares, laboratoriais e a classificação OMS 2008 / Myelodysplasic symdrome: molecular and laboratorial aspects and the 2008 WHO classification

As síndromes mielodisplásicas (SMDs) são caracterizadas por uma desordem clonal de células primordiais (stem cell) e hematopoese ineficaz que levam à displasia de uma ou mais linhagens celulares da medula óssea, citopenias periféricas e instabilidade genética, as quais aumentam o risco de transformação à leucemia mieloide aguda. Esse grupo heterogêneo de doenças hematopoéticas pode surgir como doença primária, que possui etiologia variada e não completamente definida, ou secundária ao tratamento quimioterápico ou radioterápico para outras neoplasias. O surgimento e aprimoramento de tecnologias de diagnóstico geraram uma melhor compreensão dos processos envolvidos na gênese e evolução das SMDs, o que possibilitou o desenvolvimento de marcadores de diagnóstico e acompanhamentos cada vez mais precoces e específicos. No ano de 2008, a Organização Mundial da Saúde (OMS) redefiniu os critérios para classificação das SMDs, dividindo-as em sete subgrupos. Nessa classificação foram incluídos novos aspectos imunofenotípicos, genéticos, citomorfológicos e moleculares, o que tornou o domínio e o acesso a tecnologias de ponta imprescindíveis para a realização do diagnóstico das SMDs. Apesar dos avanços tecnológicos, alguns pontos, como as bases moleculares da transformação de SMD para LMA, ainda não estão bem esclarecidos, fazendo necessária a continuação de estudos nessa área. Diante disso, essa revisão busca compilar dados atuais dos aspectos moleculares e laboratoriais das SMDs.

Myelodysplastic syndromes (MDSs) are characterized by a stem cell clonal disorder and ineffective hematopoiesis which causes dysplasia in one or more bone marrow hematopoietic cell lineages, peripheral cytopenia and genetic instability with enhanced risk to transform into acute myeloid leukemia (AML). This heterogeneous group of hematopoietic diseases can develop as primary diseases, which posses a variable and not completely defined etiology, or as secondary to chemotherapy or radiotherapy for other neoplasias. The evolution of diagnostic tests has improved comprehension of the process involved in the genesis and evolution of MDSs, making the development of earlier and more specific tests for diagnosis and follow ups possible. In 2008, the World Health Organization (WHO) redefined the criteria for the classification of MDSs, dividing them into seven subgroups. This classification included new immunophenotypic, genetic, cytomorphologic and molecular features, which are essential for the diagnosis of MDSs and for a better comprehension of the disease. Despite technological advances, some details, such as the molecular basis of the transformation of MDS to AML, are still not completely understood, which makes further studies in this field necessary. Hence, the objective of this review is to make a compilation of recent molecular and laboratory aspects of MDS.

Importância da análise da proteína Pax-5 no diagnóstico diferencial entre linfoma de Hodgkin e linfoma difuso de grandes células B em biópsias de mediastino / The importance of Pax-5 protein immunostaining in the differential diagnosis between Hodgkin's lymphoma and diffuse large B-cell lymphoma in biopsies of the mediastinum

O linfoma de Hodgkin (LH) e o linfoma difuso de grandes células B (LDGCB) são neoplasias derivadas de células B, que apresentam marcadores imunofenotípicos em comum, e, por isso, em alguns casos onde ocorre sobreposição morfológica torna-se difícil o diagnóstico diferencial entre eles. O grau de dificuldade aumenta quando o tumor é localizado no mediastino. O fato de a biópsia de mediastino ser um procedimento ainda mais invasivo que a maioria das outras biópsias, muitas vezes faz com que sejam coletadas quantidades insuficientes de amostra, o que dificulta a análise das características morfológicas da linfoproliferação. Considerando tais dificuldades, neste trabalho investigaremos a expressão imuno-histoquímica da proteína Pax-5 no diagnóstico diferencial de LH e LDGCB. Foram analisadas amostras de 14 pacientes, sendo dez com LDGCB e quatro com LH. O estudo imuno-histoquímico com Pax-5 mostrou 100 por cento de positividade nuclear para LDGCB. Porém, destes, 30 por cento mostraram positividade forte (+++); 50 por cento moderada (++); 20 por cento fraca (+). Já nas amostras de LH, 50 por cento obtiveram marcação focal e fraca nas células de Reed/Sternberg (CRS) e 50 por cento foram negativas. A marcação focal e fraca, ou até negativa, do Pax-5 em LH pode ser um ponto importante para o diagnóstico diferencial, uma vez que difere muito da marcação visualizada no LDGCB. Assim, é possível concluir que o anticorpo Pax-5 é um bom marcador para ser usado em conjunto com outros marcadores no painel de rotina e, quando associado à clínica, pode ser muito útil no diagnóstico diferencial entre LDGCB e LH em linfoma de mediastino.

Hodgkin's Lymphoma (HL) and diffuse large B-cell Lymphoma (DLBCL) are neoplasias derived from B cells that present the same immunophenotypic markers, making the differential diagnosis between them very difficult particularly in cases where morphological overlapping occurs. An extra difficulty exists when the tumor is located in the mediastinum, thereby demanding a more invasive biopsy. In addition, frequently an excessively small sample is collected, putting the analysis of the morphological characteristics of lymphoproliferation at risk. The goal of this study was to evaluate PAX-5 as a marker to distinguish HL from DLBCL. Overall, 10 out of 14 studied cases had a diagnosis of DLBCL and 4 patients of HL. The Pax-5 immunohistochemical staining showed 100 percent positivity in the LBCL study group. However, 30 percent showed strong positivity (+++), 50 percent moderate (++) and 20 percent weak (+). On the other hand, 50 percent of the HL group showed a weak focal pattern of staining of the Reed/Sternberg Cells (RSC), whereas the other 50 percent showed negativity. The weak focal pattern as well as the negative staining pattern of PAX-5 in HL may be an important key in the differential diagnosis as it is very different from DLBCL. Hence, we suggest that the PAX-5 antibody is a good immunomarker and may be used with other markers in the laboratory routine. It is also very useful when associated to clinical features of patients to reach a differential diagnosis between DLBCL and HL mediastinal lymphoma.

Avaliação dos índices hematimétricos emitidos pelos contadores hematológicos Pentra 120 Range e Sysmex XT-2000i / Evaluation of the hematimetric index emitted by hematological accountants Pentra 120 Screeches and Sysmex XT-2000i

O avanço tecnológico permitiu o desenvolvimento de modernos contadores automatizados de células sanguíneas, os quais combinam diferentes métodos de avaliação de índices hematológicos. Considerando a importância destes índices no diagnóstico diferencial de anemias e a variabilidade dos resultados emitidos pelos contadores Sysmex XT-2000i e Pentra 120 Range através da comparação dos valores dos parâmetros hematimétricos obtidos pelos contadores e a análise morfológica da distensão do sangue periférico. Foram analisados aleatoriamente 444 hemogramas de pacientes atendidos no Laboratório de Análises Clínicas do HU-UFSC, Processados pelos contadores Pentra 120 Range e Sysmex XT-2000i e comparados com a análise morfológica das células. Além disso, a comparação dos valores de HCM e CHCM com a avaliação morfológica mostrou que os critérios utilizados pelos contadores Sysmex XT-2000i e Pentra 120 Range na análise do HCM são os mais compatíveis com a microscopia. Entretanto, em relação ao CHCM, apenas os resultados do Pentra 120 Range foram compatíveis estatisticamente. Assim, concluímos que o uso dos parâmetros hematimétricos devem ser criteriosos, e, que dependem do contador de células usado pelo laboratório. Por isso, o controle de qualidade é imprescindível, e, além disso, amostras com valores fora daqueles de referência requerem avaliação morfológica por microscopia óptica.

Triagem neonatal como um problema de saúde pública / The importance of the hemoglobinopathy detection in National Neonatal Screening Programs

Estudos realizados na população brasileira revelam que, no Brasil, existem aproximadamente 10 milhões de indivíduos heterozigotos para os genes da Hb S, da Hb C e da talassemia beta. Embora mais de 700 hemoglobinas variantes tenham sido descritas, apenas a forma homozigótica para HbS apresenta expressão clínica mais evidente; no entanto, as formas heterozigóticas HbAS e HbSC também representam um problema de saúde pública. Em geral, os indivíduos heterozigóticos desconhecem o fato de serem portadores assintomáticos (AS, AC) e, por isso, facilitam a propagação desses genes anômalos e sua interação com outras hemoglobinas variantes, talassemias, enzimopatias e esferocitoses. Como medida de prevenção e controle das hemoglobinopatias no Brasil, o Ministério da Saúde instituiu a portaria 822/01, que inclui a triagem de hemoglobinopatias no programa nacional de triagem neonatal (PNTN). O objetivo deste trabalho foi analisar a prevalência das hemoglobinopatias em crianças nascidas no período de janeiro a junho de 2003 no estado de Santa Catarina. Do total de 40.028 amostras analisadas, 399 (1 por cento) apresentaram hemoglobinopatias, e, dessas, 88,47 por cento apresentaramm o fenótipo AS; 7,76 por cento AC; 2,25 por cento AD; 0,75 por cento SS e 0,5 por cento SC. A triagem de hemoglobinopatias é uma análise importante para a prevenção das hemoglobinopatias, as quais representam um problema de saúde pública.