Laboratory workflow for optimizing leukocyte count and differential in synovial fluids on Sysmex XN-1000.

Introduction: Falsely elevated synovial white blood cell (WBC) counts using automated hematology analyzers have been reported particularly in the setting of joint arthroplasty. We evaluated the implementation of a laboratory workflow based on Sysmex XN-1000-automated cell counting and scattergram interpretation.

Methods: WBC and differential were measured for 76 synovial fluid samples (29 native joints and 47 with joint arthroplasties) with Sysmex XN-1000 and manual methods.

Chronic myeloid leukemia (CML) in children and adolescents-Clinicopathological findings.

Background: Barely two per million Belgian children/adolescents are diagnosed with chronic myeloid leukemia (CML) annually. In this retrospective study, we aimed to investigate the diagnostic features, clinical and laboratory characteristics, and treatment outcome of this rare entity.

Methods: Medical records of all pediatric CML patients (age ≤ 17 years) diagnosed at the University Hospitals Leuven between 1986 and 2021 were reviewed.

Shallow whole-genome sequencing of bone marrow aspirates in myelodysplastic neoplasms: A retrospective comparison with cytogenetics.

Copy number alterations (CNA) are powerful prognostic markers in myelodysplastic neoplasms (MDS) and are routinely analyzed by conventional cytogenetic analysis (CCA) on bone marrow (BM). Although CCA is still the gold standard, it requires extensive hands-on time and highly trained staff for the analysis, making it a laborious technique. To reduce turn-around-time per case, shallow whole genome sequencing (sWGS) technologies offer new perspectives for the diagnostic work-up of this disorder.

Homozygous DBF4 mutation as a cause of severe congenital neutropenia.

Background: Severe congenital neutropenia presents with recurrent infections early in life as a result of arrested granulopoiesis. Multiple genetic defects are known to block granulocyte differentiation; however, a genetic cause remains unknown in approximately 40% of cases.

Objective: We aimed to characterize a patient with severe congenital neutropenia and syndromic features without a genetic diagnosis.

t(1;7;22)(p13;q21;q13) is a novel 3-way variant of t(1;22)(p13;q13) neonatal acute megakaryoblastic leukemia: A case report.

Acute megakaryoblastic leukemia (AMKL) is a rare disease, occurring mostly in infants and young children. The chromosomal translocation t(1;22)(p13;q13), resulting in the RBM15-MKL1 fusion gene, is a recurrent and diagnostic translocation in infants with AMKL. The present case report describes a case of a newborn girl, without Down's syndrome, with congenital AMKL.

Antiviral treatment with fluoxetine for rituximab-associated chronic echovirus 13 meningoencephalitis and myofasciitis.

Background And Purpose: Enterovirus infections pose a serious threat for patients with humoral deficiencies and may be lethal, whilst the efficacy of proposed treatment options such as corticosteroids, intravenous immunoglobulins and fluoxetine remains debated.

Methods: Viral clearance was investigated in a patient with rituximab-induced B-cell depletion and chronic echovirus 13 (E13) meningoencephalitis/myofasciitis in response to intravenous immunoglobulins and fluoxetine using sequential semi-quantitative E13 viral load measurements by real-time reverse transcription polymerase chain reaction. Fluoxetine concentrations in plasma and cerebrospinal fluid were determined by liquid chromatography mass spectrometry.

Monitoring of Leukemia Clones in B-cell Acute Lymphoblastic Leukemia at Diagnosis and During Treatment by Single-cell DNA Amplicon Sequencing.

Acute lymphoblastic leukemia (ALL) is characterized by the presence of chromosomal changes, including numerical changes, translocations, and deletions, which are often associated with additional single-nucleotide mutations. In this study, we used single cell-targeted DNA sequencing to evaluate the clonal heterogeneity of B-ALL at diagnosis and during chemotherapy treatment. We designed a custom DNA amplicon library targeting mutational hotspot regions (in 110 genes) present in ALL, and we measured the presence of mutations and small insertions/deletions (indels) in bone marrow or blood samples from 12 B-ALL patients, with a median of 7973 cells per sample.

The role of microscopic bone marrow examination and [I]MIBG scintigraphy in detection of bone marrow involvement in patients with neuroblastoma.

Objectives: For the detection of bone marrow (BM) metastases in patients with neuroblastoma, microscopic BM examination and [I]MIBG scintigraphy are advised. The aims of this study were to assess the concordance of [I]MIBG and microscopic BM examination (aspirate and biopsy) in detecting BM involvement and to compare invasive disease in BM biopsies and aspirates, both at diagnosis and before autologous stem cell collection (ASCC).

Methods: Fifty-five patients with stage 4 or stage 4S disease were included, and 37 of them received an autologous hematopoietic stem cell transplantation (AHSCT).

Oncogenic cooperation between TCF7-SPI1 and NRAS(G12D) requires β-catenin activity to drive T-cell acute lymphoblastic leukemia.

Spi-1 Proto-Oncogene (SPI1) fusion genes are recurrently found in T-cell acute lymphoblastic leukemia (T-ALL) cases but are insufficient to drive leukemogenesis. Here we show that SPI1 fusions in combination with activating NRAS mutations drive an immature T-ALL in vivo using a conditional bone marrow transplant mouse model. Addition of the oncogenic fusion to the NRAS mutation also results in a higher leukemic stem cell frequency.

Next generation sequencing in therapy-related myeloid neoplasms compared to myeloid neoplasms.

Introduction: Therapy-related myeloid neoplasms (t-MN) are frequently categorized according to previous therapy or pattern of cytogenetic abnormalities. Our objective was to evaluate and compare the mutational profile of and t-MN by next generation sequencing.

Methods: Sixty-four samples from patients with t-MN, previously treated for a solid tumor (mainly breast), or AML, MDS, MDS/MPN were selected for our study.

PSEN1-selective gamma-secretase inhibition in combination with kinase or XPO-1 inhibitors effectively targets T cell acute lymphoblastic leukemia.

Background: T cell acute lymphoblastic leukemia (T-ALL) is a high-risk subtype that comprises 10-15% of childhood and 20-25% of adult ALL cases. Over 70% of T-ALL patients harbor activating mutations in the NOTCH1 signaling pathway and are predicted to be sensitive to gamma-secretase inhibitors. We have recently demonstrated that selective inhibition of PSEN1-containing gamma-secretase complexes can overcome the dose-limiting toxicity associated with broad gamma-secretase inhibitors.

Assessment of droplet digital polymerase chain reaction for measuring BCR-ABL1 in chronic myeloid leukaemia in an international interlaboratory study.

Measurement of BCR activator of RhoGEF and GTPase -ABL proto-oncogene 1, non-receptor tyrosine kinase (BCR-ABL1) mRNA levels by reverse transcription quantitative polymerase chain reaction (RTqPCR) has been critical to treatment protocols and clinical trials in chronic myeloid leukaemia; however, interlaboratory variation remains a significant issue. Reverse transcriptase droplet digital PCR (RTddPCR) has shown potential to improve testing but a large-scale interlaboratory study is required to definitively establish this. In the present study, 10 BCR-ABL1-positive samples with levels ranging from molecular response (MR) -MR were tested by 23 laboratories using RTddPCR with the QXDX BCR-ABL %IS kit.

Case Report: VEXAS Syndrome: From Mild Symptoms to Life-Threatening Macrophage Activation Syndrome.

Recently, a novel disorder coined VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome was identified in patients with adult-onset inflammatory syndromes, often accompanied by myelodysplastic syndrome1. All patients had myeloid lineage-restricted somatic mutations in UBA1 affecting the Met41 residue of the protein and resulting in decreased cellular ubiquitylation activity and hyperinflammation. We here describe the clinical disease course of two VEXAS syndrome patients with somatic UBA1 mutations of which one with a mild phenotype characterized by recurrent rash and symmetric polyarthritis, and another who was initially diagnosed with idiopathic multicentric Castleman disease and developed macrophage activation syndrome as a complication of the VEXAS syndrome.

Ultra-low coverage whole genome sequencing of ccfDNA in multiple myeloma: A tool for laboratory routine?

Unlabelled: Multiple myeloma (MM), is a heterogeneous disease in which chromosomal abnormalities are important for prognostic risk stratification. Cytogenetic profiling with FISH on plasma cells from bone marrow samples (BM-PCs) is the current gold standard, but variable infiltration of plasma cells or failed aspiration can hamper this process. Ultra-low coverage sequencing (ULCS) of circulating cell-free DNA (ccfDNA) may offer a minimally invasive alternative for the work-up of these cases.

Malignant invasion of the cerebrospinal fluid in adult and paediatric patients with haematological and solid malignancies: a monocentric retrospective study.

Objectives: In this study, we describe the clinical presentation, the cerebrospinal fluid (CSF) characteristics and outcome of children and adults with leptomeningeal invasion due to haematological and solid malignancies.

Methods: Routine CSF samples analyzed from 2008 to 2018 at our institution were retrospectively reviewed for the presence of malignant cells based on cytomorphological analysis.

Results: Leptomeningeal invasion was identified in 212 patients: 45 children versus 167 adults, and 92 haematological versus 120 solid malignancies.

The integration of Sysmex XN-9100' WPC channel reflex testing in the detection of reactive versus malignant blood samples.

Introduction: Sysmex XN-9100 (Sysmex, Kobe, Japan) system has an optional White Progenitor Cell (WPC) channel. While the White Differentiation (WDF) channel reports a combined flag for blasts/abnormal lymphocytes, WPC channel specifies flagging into a separate flag for each cell type or removes the flag entirely. Aim of this study was to evaluate the added value of this WPC channel in the detection of malignant samples.

The XPO1 Inhibitor KPT-8602 Synergizes with Dexamethasone in Acute Lymphoblastic Leukemia.

Purpose: KPT-8602 (Eltanexor) is a second-generation exportin-1 (XPO1) inhibitor with potent activity against acute lymphoblastic leukemia (ALL) in preclinical models and with minimal effects on normal cells. In this study, we evaluated whether KPT-8602 would synergize with dexamethasone, vincristine, or doxorubicin, three drugs currently used for the treatment of ALL.

Experimental Design: First, we searched for the most synergistic combination of KPT-8602 with dexamethasone, vincristine, or doxorubicin in both B-ALL and T-ALL cell lines using proliferation and apoptosis as a readout.

Single-cell DNA amplicon sequencing reveals clonal heterogeneity and evolution in T-cell acute lymphoblastic leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive leukemia that is most frequent in children and is characterized by the presence of few chromosomal rearrangements and 10 to 20 somatic mutations in protein-coding regions at diagnosis. The majority of T-ALL cases harbor activating mutations in NOTCH1 together with mutations in genes implicated in kinase signaling, transcriptional regulation, or protein translation. To obtain more insight in the level of clonal heterogeneity at diagnosis and during treatment, we used single-cell targeted DNA sequencing with the Tapestri platform.

Defective Sec61α1 underlies a novel cause of autosomal dominant severe congenital neutropenia.

Background: The molecular cause of severe congenital neutropenia (SCN) is unknown in 30% to 50% of patients. SEC61A1 encodes the α-subunit of the Sec61 complex, which governs endoplasmic reticulum protein transport and passive calcium leakage. Recently, mutations in SEC61A1 were reported to be pathogenic in common variable immunodeficiency and glomerulocystic kidney disease.

Ultra-low depth sequencing of plasma cell DNA for the detection of copy number aberrations in multiple myeloma.

Cytogenetic abnormalities are powerful prognostic factors in multiple myeloma (MM) and are routinely analyzed by FISH on bone marrow (BM) plasma cells (PC). Although considered the gold standard, FISH experiments can be laborious and expensive. Therefore, array-CGH (aCGH) has been introduced as an alternative approach for detecting copy number aberrations (CNA), reducing the number of FISH experiments per case and yielding genome-wide information.