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.

Abstract Background Evidence suggests that monoclonal B-cell lymphocytosis precedes all chronic lymphocytic leukemia cases, although the molecular mechanisms responsible for disease progression are not understood. Aberrant miRNA expression may contribute to the pathogenesis of chronic lymphocytic leukemia. The objective of this study was to compare miRNA expression profiles of patients with Binet A chronic lymphocytic leukemia with those of subjects with high-count monoclonal B-cell lymphocytosis and healthy volunteers (controls). Methods Twenty-one chronic lymphocytic leukemia patients, 12 subjects with monoclonal B-cell lymphocytosis and ten healthy volunteers were enrolled in this study. Flow cytometry CD19+CD5+-based cell sorting was performed for the chronic lymphocytic leukemia and monoclonal B-cell lymphocytosis groups and CD19+ cells were sorted to analyze the control group. The expressions of miRNAs (miR-15a, miR-16-1, miR-29b, miR-34a, miR-181a, miR-181b and miR-155) were determined by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Results Significant differences between the expressions in the chronic lymphocytic leukemia and monoclonal B-cell lymphocytosis groups were restricted to the expression of miR-155, which was higher in the former group. A comparison between healthy controls and monoclonal B-cell lymphocytosis/chronic lymphocytic leukemia patients revealed higher miR-155 and miR-34a levels and lower miR-15a, miR-16-1, miR-181a and miR-181b in the latter group. Conclusions Our results show a progressive increase of miR-155 expression from controls to monoclonal B-cell lymphocytosis to chronic lymphocytic leukemia. The role of miR-155 in the development of overt chronic lymphocytic leukemia in individuals with monoclonal B-cell lymphocytosis must be further analyzed.

Abstract Objective: To evaluate factors predictive for relapse in a cohort of adult patients with acute promyelocytic leukemia monitored by molecular methods during consolidation and during at least one month of maintenance therapy. Methods: The charts and laboratory data of 65 adult patients with acute promyelocytic leukemia treated according to the International Consortium on Acute Promyelocytic Leukemia 2006 protocol were reviewed. The identification of the promyelocytic leukemia-retinoic acid receptor-alpha gene rearrangement at diagnosis, post-induction, post-consolidation and during maintenance treatment was performed by qualitative and quantitative reverse transcription polymerase chain reaction. Results: Eighty-nine patients were diagnosed with acute promyelocytic leukemia over a seven-year period and of these 65 were eligible for treatment with the protocol. Among the 45 patients who received consolidation and maintenance treatment, six (13%) relapsed, three of whom presented hematologic and three presented molecular relapse. The first relapses occurred at a median of 39 months. Relapsed patients were from all risk groups (low, intermediate and high) and both morphological types (M3 and M3variant) were found. Three of these patients are alive and in molecular remission after salvage treatment. There were no statistically significant differences regarding gender, age, risk group, morphology, promyelocytic leukemia breakpoint cluster region, use of all-trans retinoic acid, development of differentiation syndrome and number of days to complete remission between the patients who relapsed and those who did not. Conclusion: Our results reinforce the importance of prolonged monitoring of acute promyelocytic leukemia patients using molecular methods to detect relapse early.

Acute promyelocytic leukemia is characterized by gene rearrangements that always involve the retinoic acid receptor alpha on chromosome 15. In the majority of patients t(15;17) is detected, which generates the promyelocytic leukemia gene/retinoic acid receptor alpha rearrangement. This rearrangement interacts with several proteins, including the native promyelocytic leukemia gene, thus causing its delocalization from the nuclear bodies, impairing its function. The immunofluorescence staining technique using the anti-PML antibody may be used to provide a rapid diagnosis and to immediately start therapy using all-trans retinoic acid. The experience of the International Consortium on Acute Promyelocytic Leukemia has demonstrated that early mortality was significantly reduced by adopting the immunofluorescence technique. All-trans retinoic acid combined with chemotherapy is the standard therapy; this promotes complete remission rates greater than 90% and cure rates of nearly 80%. However, early mortality is still an important limitation and hematologists must be aware of the importance of treating newly diagnosed acute promyelocytic leukemia as a medical emergency.

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.