ABSTRACT Currently, there are four CAR-T products commercially available on the market. CAR-T cells have shown high remission rates and they represent an effective treatment option for patients with resistant or refractory B cell malignancies. Approval of these cell therapy products came after an extended period of preclinical evaluation that demonstrated unprecedented efficacy in this difficult-to-treat patient population. This review article outlines the main preclinical evaluations needed for CAR T cell product development.

OBJECTIVES: The outcomes of refractory and relapsed acute myeloid leukemia (AML) patients in developing countries are underreported, even though the similar classic regimens are widely used. METHODS: We conducted a retrospective comparison of “MEC” (mitoxantrone, etoposide, and cytarabine) and “FLAG-IDA” (fludarabine, cytarabine, idarubicin, and filgrastim) in adults with first relapse or refractory AML. RESULTS: In total, 60 patients were included, of which 28 patients received MEC and 32 received FLAG-IDA. A complete response (CR) rate of 48.3% was observed. Of the included patients, 16 (27%) died before undergoing bone marrow assessment. No statiscally significant difference in CR rate was found between the two protocols (p=0.447). The median survival in the total cohort was 4 months, with a 3-year overall survival (OS) rate of 9.7%. In a multivariable model including age, fms-like tyrosine kinase 3 (FLT3) status, and stem-cell transplantation (SCT), only the last two indicators remained significant: FLT3-ITD mutation (hazard ratio [HR]=4.6, p<0.001) and SCT (HR=0.43, p=0.01). CONCLUSION: In our analysis, there were no significant differences between the chosen regimens. High rates of early toxicity were found, emphasizing the role of supportive care and judicious selection of patients who are eligible for intensive salvage therapy in this setting. The FLT3-ITD mutation and SCT remained significant factors for survival in our study, in line with the results of previous studies.

A leucemia promielocítica aguda (LPA) é geralmente acompanhada por anormalidades da coagulação usualmente descritas como coagulação intravascular disseminada e que são a principal causa de mortalidade precoce. A ativação anormal da cascata de coagulação e a hiperfibrinólise desempenham importante papel na patogênese da diátese hemorrágica, mas a contribuição de cada fator varia de caso a caso. Apresentamos aqui uma revisão dos principais achados laboratoriais e da recomendação para o manejo clínico da coagulopatia associada a LPA.

Acute promyelocytic leukemia is frequently accompanied by coagulation abnormalities usually described as laboratorial disseminated intravascular coagulation, which is the main cause of morbidity and early mortality. Aberrant activation of the coagulation cascade and hyperfibrinolysis play an important role in the pathogenesis of bleeding diathesis, but their contribution varies from case to case. Here we review the main laboratorial findings and the recommended clinical management of coagulopathy associated with acute promyelocytic leukemia.

A imunofenotipagem por citometria de fluxo (CMF) é atualmente uma ferramenta indispensável para o diagnóstico hematopatológico. Nos últimos anos muitos progressos foram alcançados em instrumentação, novos anticorpos e fluorocromos e programas de análise. Consequentemente, houve um grande avanço no conhecimento da patogênese das neoplasias hematológicas e novos marcadores diagnósticos e prognósticos foram descritos. Revisamos aqui a contribuição destas novas técnicas no diagnóstico diferencial de pacientes com bi- ou pancitopenia e linfocitose. São apresentados os achados mais frequentes e as dificuldades na interpretação dos resultados. Além disto, a importância do uso concomitante de um conjunto de outras técnicas diagnósticas é demonstrada.

The use of flow cytometry for immunophenotyping is currently an essential tool in the diagnosis of hematological abnormalities. In recent years, new equipment, antibodies, fluorochromes and computer programs have become available. As a result, a better understanding of the pathogeneses of hematological malignancies has emerged and new markers with diagnostic and prognostic relevance have been described. Here we review how this new technology may contribute to the differential diagnosis of patients with bi- or pancytopenia and of lymphocytosis. The common findings as well as the difficulties in interpreting the results obtained by flow cytometry will be discussed. The importance of the concomitant analyses by different methods is also demonstrated.

As sombras nucleares têm sido classicamente associadasà leucemia linfocítica crônica (LLC), embora possam ser encontradas nos esfregaços do sangue periférico de outras doenças linfoproliferativas B crônicas (DLBC). Nesse estudo, nós investigamos se a porcentagem de sombras nucleares nos esfregaços do sangue periférico pode ser utilizada na prática clínica da hematologia para diferenciar a LLC das outras DLBC. Foram analisados os esfregaços do sangue periférico de 63 pacientes com o diagnóstico de LLC e 62 com outras DLPC. Trezentas células, entre células linfoides e sombras nucleares, foram contadas em cada esfregaço. A comparação da porcentagem de sombras nucleares entre os dois grupos foi realizada e, subsequentemente, foram fixados 5 cut-offs de mais de 10%, 20%, 30%, 40% e 50% de sombras nucleares com o propósito de definir um caso como "positivo para sombras nucleares" e verificar se havia diferenças entre a LLC e as outras DLBC. A porcentagem das sombras nucleares em pacientes com LLC (mediana 26%, 4%-86%) foi maior do que em pacientes com DLBC (mediana 14%, 1%-64%). Entretanto, nenhum dos cut-offs testados apresentou valores apropriados de sensibilidade, especificidade e valor preditivo positivo para distinguir os dois grupos. Desde queé necessário se dispor de um único valor de cut-off com alta sensibilidade, especificidade e valor preditivo positivo para inferir o diagnóstico de CLL na prática clínica, conclui-se que as sombras nucleares não são úteis para diferenciar a LLC das outras DLBC.

Smudge cells has been classically associated with chronic lymphocytic leukemia (CLL), but they are found in peripheral blood tests for other chronic B-cell lymphoproliferative diseases (CLD). We investigated whether the percentage of smudge cells in peripheral blood smears can be used in the clinical practice to differentiate CLL from other B-cell CLD. The peripheral blood smears of 63 patients with the diagnosis of CLL and 62 with other B-cell CLD were analyzed. Three hundred cells (both lymphoid cells and smudge cells) were counted for each peripheral blood smear. A comparison of the percentage of smudge cells between the two groups was performed and, subsequently, 5 cut-off values were fixed (10%, 20%, 30%, 40% and 50% of smudge cells) with the aim of defining cases as "positive" or "negative" for smudge cells and verifying whether there are any differences between CLL and the other B-cell CLD. The percentage of smudge cells in patients with CLL (median 26%, 4%-86%) was higher than in patients with B-cell CLD (median 14%, 1%-64%). However, none of the cut-off values tested presented suitable values of sensitivity, specificity and positive predictive value to separate the two groups. As it is necessary to have a single cut-off value with high sensitivity, specificity and positive predictive value to infer the diagnosis of CLL in the clinical practice, we concluded that smudge cells are not fitting to differentiate CLL from other B-cell CLD.

A síndrome da diferenciação (DS) é um efeito colateral que pode ocorrer em pacientes com leucemia promielocítica aguda (APL) tratados com ácido all-trans-retinóico (ATRA) ou trióxido de arsênico (ATO), sendo caracterizada pelo aumento da transmigração de leucócitos. Vários mecanismos celulares e moleculares participam no desenvolvimento da DS. Esta revisão discute as mudanças na expressão de moléculas de adesão induzidas durante o tratamento com ATRA e ATO e possíveis implicações na patogênese desta complicação potencialmente fatal.

Differentiation syndrome is a treatment complication which can occur in acute promyelocytic leukemia (APL) patients treated with all-trans retinoic acid (ATRA) or arsenic trioxide (ATO), which is characterized by enhanced leukocyte transmigration. Several cellular and molecular mechanisms participate in differentiation syndrome development. This review discusses the changes in expression of adhesion molecules induced during ATRA and ATO treatments and their possible implications in the pathogenesis of this potentially fatal complication.

O esquema de Durie / Salmon continua a ser utilizado para estadiar os pacientes com mieloma múltiplo. Recentemente, um novo sistema mais simples e eficaz foi proposto. O "International Myeloma Working Group" realizou um estudo retrospectivo com 11.179 pacientes e a partir destes dados propôs a criação de um "International Staging System (ISS)" utilizando os níveis séricos de ß2 microglobulina e de albumina ao diagnóstico. Além do ISS a pesquisa está voltada para identificar alterações citogenéticas e moleculares que se correlacionem com o prognóstico no mieloma múltiplo. Estes fatores prognósticos têm sido utilizados para estratificar pacientes em ensaios clínicos com resultados promissores.

The Durie/Salmon staging system continues to be used worldwide in patients with multiple myeloma. However, in recent years, new systems have been proposed. The International Myeloma Working Group performed a retrospective study with 11,179 patients and proposed an "International Staging System" utilizing serum levels of â2 microglobulin and albumin. In addition, current research has focused on the usefulness of cytogenetic and molecular data as prognostic factors. These data suggest that these parameters are powerful discriminators of a poor prognostic group of myeloma patients. Indeed, these prognostic indexes have been utilized in clinical trials, with interesting and encouraging results.

A leucemia mielóide aguda (LMA) está freqüentemente associada a translocações cromossômicas recorrentes. Em muitos casos, os genes presentes nos pontos de quebra cromossômica são conhecidos e, quase todos codificam para fatores de transcrição. O gene híbrido, resultante da justaposição de exons de genes distintos, codifica para proteínas de fusão. Como estas retêm a maior parte dos domínios funcionais das proteínas selvagens, elas interferem direta ou indiretamente com regulação da transcrição gênica, conferindo vantagem à sobrevivência das células leucêmicas. A maioria dos fatores de transcrição afetados pelas translocações cromossômicas associadas a LMA pode ser agrupada numa das seguintes famílias: dos core binding factors (CBF), do receptor a do ácido retinóico (RARalfa), do homeobox (HOX), ou do mixed lineage leukemia (MLL). Estudos in vivo, empregando modelos transgênicos, revelaram um mecanismo molecular comum a estas proteínas de fusão: a desregulação da transcrição gênica via recrutamento de fatores co-ativadores ou co-repressores. Embora necessária, a expressão das proteínas de fusão não é suficiente para o desenvolvimento da leucemia. A existência de uma longa fase pré leucêmica observada nos modelos transgênicos sugere que outros eventos mutagênicos devam ocorrer para o desenvolvimento das leucemias.

Acute Myelogenous Leukemia (AML) is frequently associated with recurring chromosomal translocations, which lead to the fusion of two genes encoding transcription factors. As the moieties of these fusion proteins retain part of the functional domains of the wild-type proteins, they may interfere directly or indirectly with the transcriptional regulation of the leukemic cell, conferring survival advantage. The majority of the transcription factors commonly involved in recurring chromosomal translocations may be grouped in one of the following families: core binding factor (CBF), retinoic acid receptor alpha (RARalpha), homeobox (HOX) family, and mixed lineage leukemia (MLL). In vivo analysis of the molecular basis of leukemogenesis through the generation of transgenic mouse models revealed that a common theme is the recruitment of transcriptional co-activators and co-repressors by these fusion proteins. However, the expression of the fusion protein is not sufficient to induce full blown leukemia, as evidenced in part by the long latencies required for disease development in the transgenic models of leukemia, and therefore, second mutagenic events may contribute to AML pathogenesis.