miR-15a-5p and miR-21-5p contribute to chemoresistance in cytogenetically normal acute myeloid leukaemia by targeting PDCD4, ARL2 and BTG2

Cytarabine and daunorubicin are old drugs commonly used in the treatment of acute myeloid leukaemia (AML). Refractory or relapsed disease because of chemotherapy resistance is a major issue. microRNAs (miRNAs) were incriminated in resistance. This study aimed to identify miRNAs involved in chemoresistance in AML patients and to define their target genes. We focused on cytogenetically normal AML patients with wild-type NPM1 without FLT3-ITD as the treatment of this subset of patients with intermediate-risk cytogenetics is not well established. We analysed baseline AML samples by small RNA sequencing and compared the profile of chemoresistant to chemosensitive AML patients. Among the miRNAs significantly overexpressed in chemoresistant patients, we revealed miR-15a-5p and miR-21-5p as miRNAs with a major role in chemoresistance in AML. We showed that miR-15a-5p and miR-21-5p overexpression decreased apoptosis induced by cytarabine and/or daunorubicin. PDCD4, ARL2 and BTG2 genes were found to be targeted by miR-15a-5p, as well as PDCD4 and BTG2 by miR-21-5p. Inhibition experiments of the three target genes reproduced the functional effect of both miRNAs on chemosensitivity. Our study demonstrates that miR-15a-5p and miR-21-5p are overexpressed in a subgroup of chemoresistant AML patients. Both miRNAs induce chemoresistance by targeting three pro-apoptotic genes PDCD4, ARL2 and BTG2

Positive direct antiglobulin test in COVID-19 patients: Decision-making process.

In this unprecedented crisis of severe acute respiratory syndrome coronavirus 2 and its associated coronavirus disease 2019 (COVID-19), polymerase chain reaction and then serological testing platforms have been massively developed to face the important screening demand. Polymerase chain reaction and serological testing platforms are not the only actors impacted by the crisis, transfusion services are facing important difficulties. A positive direct antiglobulin test is frequently observed for patients encountering COVID-19. Patients with severe symptoms may develop anaemia and become good candidates for blood transfusions. The interpretation of a positive direct antiglobulin test for patients recently transfused and suffering from COVID-19 is complex. The differentiation between COVID-19 induced antibodies and possible associated transfusion alloantibodies is therefore crucial. In this context, the elution technique incorporated in an appropriate decision-making process plays its full role. This intricate topic is presented through a case report followed by literature review and finally decision-making process for COVID-19 patients necessitating red blood cells administration

Gene expression profiling reveals differences in microenvironment interaction between patients with chronic lymphocytic leukemia expressing high versus low ZAP70 mRNA

BACKGROUND: Zeta-associated protein 70 (ZAP70) is a widely recognized prognostic factor in chronic lymphocytic leukemia, but mechanisms by which its higher expression leads to a poor outcome must still be fully explained. DESIGN AND METHODS: In an attempt to unveil unfavorable cellular properties linked to high ZAP70 expression, we used gene expression profiling to identify genes associated with disparities in B cells from chronic lymphocytic leukemia patients expressing high versus low ZAP70 mRNA, measured by quantitative real-time PCR. Two groups of 7 patients were compared, selected on the basis of either high or low ZAP70 mRNA expression. RESULTS: Twenty-seven genes were differentially expressed with an FDR<10%, and several genes were significant predictors of treatment-free survival (TFS) and/or overall survival; PDE8A and FCRL family genes (down-regulated in ZAP70(+) patients) could predict TFS and overall survival; ITGA4 mRNA (up-regulated in ZAP70(+) patients) could significantly predict overall survival. Importantly, gene set enrichment analysis revealed overrepresentation of adhesion/migration genes. We therefore investigated in vitro adhesion/migration capacity of chronic lymphocytic leukemia cells into a stromal microenvironment or in response to conditioned medium. We showed that ZAP70(+) cells had better adhesion/migration capacities and only ZAP70(+) patient cells responded to microenvironment contact by CXCR4 downregulation. CONCLUSIONS: We concluded that several prognostic factors are the reflection of microenvironment interactions and that the increased adhesion/migratory capacity of ZAP70(+) cells in their microenvironment can explain their better survival and thus the aggressiveness of the disease.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Guidelines for an integrated diagnostic approach of chronic lymphoproliferative disorders in the routine laboratory of haematology in Belgium.

This paper summarizes the minimal workout of chronic lymphoproliferative disorders in a routine laboratory of haematology as recommended by a team of experienced laboratory supervisors in Belgium, taking into account the specific organisation of healthcare in Belgium, the innovations in the field of molecular analyses and related reimbursement. The starting point was essentially based upon clinical and/or haematological indications and it is emphasized that conclusions should be drawn in close dialogue with the clinician and experts in cytogenetics and histopathology. Reports made in the laboratory should be based upon an integration of cytomorphological, immunophenotypical and molecular data. These guidelines are not intended to be used as universal 'diagnostic pathways', but should be useful in developing local diagnostic pathways. It is well understood that this consensus, being valid anno 2009, may rapidly change with new technologies being introduced and new targets discovered

A novel approach for BCR-ABL1 standardization to improve International Scale estimation

Standardization of BCR-ABL1 messenger RNA quantification by real-time PCR on the International Scale (IS) is critical for monitoring therapy response in chronic myelogenous leukaemia. Since 2006, BCR-ABL1 IS standardization is propagated along reference laboratories by calculating a laboratory-specific conversion factor (CF), co-ordinated in Europe through the European Treatment and Outcome Study project. Although this process has proven successful to some extent, it has not been achievable for all laboratories due to the complexity of the process and the stringent requirements in terms of numbers of samples to be exchanged. In addition, several BCR-ABL1 IS quantification methods and secondary reference materials became commercially available. However, it was observed that different IS methods generate consistently different results.status: publishe

Diagnostic testing in myeloid malignancies by next-generation sequencing: recommendations from the commission personalised medicine

Molecular diagnostics have an increasing impact on diagnosis, risk stratification and targeted treatment in haemato-oncology. In the framework of a pilot study for the implementation of next-generation sequencing in the Belgian healthcare system, the Commission of Personalised Medicine was founded to give professional and evidence-based advice on the molecular analysis in haemato-oncology. This paper describes its recommendations for NGS analysis in myeloid malignancies. In addition, the minimally required set of genes that must be analysed is defined and algorithms for molecular workflow in myeloid malignancies are&nbsp;proposed.</p