A comparative study of blood cell count in four automated hematology analyzers: An evaluation of the impact of preanalytical factors.

Differential white blood cell counts are frequently used in diagnosis, patient stratification, and treatment selection to optimize therapy responses. Referral laboratories are often used but challenged with use of different hematology platforms, variable blood shipping times and storage conditions, and the different sensitivities of specific cell types. To extend the scientific literature and knowledge on the temporal commutability of blood samples between hematology analyzers, we performed a comparative ex-vivo study using four of the most utilized commercial platforms, focusing on the assessment of eosinophils given its importance in asthma management. Whole blood from healthy volunteers with and without atopy (n = 6+6) and participants with eosinophilic asthma (n = 6) were stored under different conditions (at 4, 20, 30, and 37°C, with or without agitation) and analyzed at different time points (3, 6, 24, 48 and 72h post-sampling) in parallel on the Abbott CELL-DYN Sapphire, Beckman Coulter DxH900, Siemens ADVIA 2120i and Sysmex XN-1000V. In the same blood samples, eosinophil-derived neurotoxin (EDN), eosinophil activation and death markers were analyzed. All platforms gave comparable measurements of cell differentials on fresh blood within the same day of sampling. However, by 24 hours, significant temporal and temperature-dependent differences were observed, most markedly for eosinophils. None of the platforms performed perfectly across all temperatures tested during the 72 hours, showing that handling conditions should be optimized depending on the cell type of interest and the hematology analyzer. Neither disease status (healthy vs. asthma) nor agitation of the sample affected the cell quantification result or EDN release. The eosinophil activation markers measured by flow cytometry increased with time, were influenced by temperature, and were higher in those with asthma versus healthy participants. In conclusion, hematology analyzer, time window from sampling until analysis, and temperature conditions must be considered when analyzing blood cell differentials, particularly for eosinophils, via central labs to obtain counts comparable to the values obtained in freshly sampled blood.

Multi-omics links IL-6 trans-signalling with neutrophil extracellular trap formation and Haemophilus infection in COPD.

BACKGROUND: Interleukin (IL)-6 trans-signalling (IL-6TS) is emerging as a pathogenic mechanism in chronic respiratory diseases; however, the drivers of IL-6TS in the airways and the phenotypic characteristic of patients with increased IL-6TS pathway activation remain poorly understood. OBJECTIVE: Our aim was to identify and characterise COPD patients with increased airway IL-6TS and to elucidate the biological drivers of IL-6TS pathway activation. METHODS: We used an IL-6TS-specific sputum biomarker profile (soluble IL-6 receptor (sIL-6R), IL-6, IL-1ß, IL-8, macrophage inflammatory protein-1ß) to stratify sputum data from patients with COPD (n=74; Biomarkers to Target Antibiotic and Systemic Corticosteroid Therapy in COPD Exacerbation (BEAT-COPD)) by hierarchical clustering. The IL-6TS signature was related to clinical characteristics and sputum microbiome profiles. The induction of neutrophil extracellular trap formation (NETosis) and IL-6TS by Haemophilus influenzae were studied in human neutrophils. RESULTS: Hierarchical clustering revealed an IL-6TS-high subset (n=24) of COPD patients, who shared phenotypic traits with an IL-6TS-high subset previously identified in asthma. The subset was characterised by increased sputum cell counts (p=0.0001), persistent sputum neutrophilia (p=0.0004), reduced quality of life (Chronic Respiratory Questionnaire total score; p=0.008), and increased levels of pro-inflammatory mediators and matrix metalloproteinases in sputum. IL-6TS-high COPD patients showed an increase in Proteobacteria, with Haemophilus as the dominating genus. NETosis induced by H. influenzae was identified as a potential mechanism for increased sIL-6R levels. This was supported by a significant positive correlation between sIL-6R and NETosis markers in bronchoalveolar lavage fluid from COPD patients. CONCLUSION: IL-6TS pathway activation due to chronic colonisation with Haemophilus may be an important disease driver in a subset of COPD patients.

A MALT1 inhibitor suppresses human myeloid DC, effector T-cell and B-cell responses and retains Th1/regulatory T-cell homeostasis.

The paracaspase mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1) regulates nuclear-factor-kappa-B (NF-κB) activation downstream of surface receptors with immunoreceptor tyrosine-based activation motifs (ITAMs), such as the B-cell or T-cell receptor and has thus emerged as a therapeutic target for autoimmune diseases. However, recent reports demonstrate the development of lethal autoimmune inflammation due to the excessive production of interferon gamma (IFN-É£) and defective differentiation of regulatory T-cells in genetically modified mice deficient in MALT1 paracaspase activity. To address this issue, we explored the effects of pharmacological MALT1 inhibition on the balance between T-effector and regulatory T-cells. Here we demonstrate that allosteric inhibition of MALT1 suppressed Th1, Th17 and Th1/Th17 effector responses, and inhibited T-cell dependent B-cell proliferation and antibody production. Allosteric MALT1 inhibition did not interfere with the suppressive function of human T-regulatory cells, although it impaired de novo differentiation of regulatory T-cells from naïve T-cells. Treatment with an allosteric MALT1 inhibitor alleviated the cytokine storm, including IFN-É£, in a mouse model of acute T-cell activation, and long-term treatment did not lead to an increase in IFN-É£ producing CD4 cells or tissue inflammation. Together, our data demonstrate that the effects of allosteric inhibition of MALT1 differ from those seen in mice with proteolytically inactive MALT1, and thus we believe that MALT1 is a viable target for B and T-cell driven autoimmune diseases.

Genetic variations in A20 DUB domain provide a genetic link to citrullination and neutrophil extracellular traps in systemic lupus erythematosus.

OBJECTIVES: Genetic variations in TNFAIP3 (A20) de-ubiquitinase (DUB) domain increase the risk of systemic lupus erythematosus (SLE) and rheumatoid arthritis. A20 is a negative regulator of NF-κB but the role of its DUB domain and related genetic variants remain unclear. We aimed to study the functional effects of A20 DUB-domain alterations in immune cells and understand its link to SLE pathogenesis. METHODS: CRISPR/Cas9 was used to generate human U937 monocytes with A20 DUB-inactivating C103A knock-in (KI) mutation. Whole genome RNA-sequencing was used to identify differentially expressed genes between WT and C103A KI cells. Functional studies were performed in A20 C103A U937 cells and in immune cells from A20 C103A mice and genotyped healthy individuals with A20 DUB polymorphism rs2230926. Neutrophil extracellular trap (NET) formation was addressed ex vivo in neutrophils from A20 C103A mice and SLE-patients with rs2230926. RESULTS: Genetic disruption of A20 DUB domain in human and murine myeloid cells did not give rise to enhanced NF-κB signalling. Instead, cells with C103A mutation or rs2230926 polymorphism presented an upregulated expression of PADI4, an enzyme regulating protein citrullination and NET formation, two key mechanisms in autoimmune pathology. A20 C103A cells exhibited enhanced protein citrullination and extracellular trap formation, which could be suppressed by selective PAD4 inhibition. Moreover, SLE-patients with rs2230926 showed increased NETs and increased frequency of autoantibodies to citrullinated epitopes. CONCLUSIONS: We propose that genetic alterations disrupting the A20 DUB domain mediate increased susceptibility to SLE through the upregulation of PADI4 with resultant protein citrullination and extracellular trap formation.

Bleomycin hydrolase regulates the release of chemokines important for inflammation and wound healing by keratinocytes.

Bleomycin hydrolase (BLMH) is a well-conserved cysteine protease widely expressed in several mammalian tissues. In skin, which contains high levels of BLMH, this protease is involved in the degradation of citrullinated filaggrin monomers into free amino acids important for skin hydration. Interestingly, the expression and activity of BLMH is reduced in patients with atopic dermatitis (AD) and psoriasis, and BLMH knockout mice acquire tail dermatitis. Apart from its already known function, we have discovered a novel role of BLMH in the regulation of inflammatory chemokines and wound healing. We show that lowered BLMH levels in keratinocytes result in increased release of the pro-inflammatory chemokines CXCL8 and GROα, which are upregulated in skin from AD patients compared to healthy individuals. Conditioned media from keratinocytes expressing low levels of BLMH increased chemotaxis by neutrophils and caused a delayed wound healing in the presence of low-level TNFα. This defective wound healing was improved by blocking the shared receptor of CXCL8 and GROα, namely CXCR2, using a specific receptor antagonist. Collectively, our results present a novel function of BLMH in regulating the secretion of chemokines involved in inflammation and wound healing in human keratinocytes.

PIM kinases as potential therapeutic targets in a subset of peripheral T cell lymphoma cases.

Currently, there is no efficient therapy for patients with peripheral T cell lymphoma (PTCL). The Proviral Integration site of Moloney murine leukemia virus (PIM) kinases are important mediators of cell survival. We aimed to determine the therapeutic value of PIM kinases because they are overexpressed in PTCL patients, T cell lines and primary tumoral T cells. PIM kinases were inhibited genetically (using small interfering and short hairpin RNAs) and pharmacologically (mainly with the pan-PIM inhibitor (PIMi) ETP-39010) in a panel of 8 PTCL cell lines. Effects on cell viability, apoptosis, cell cycle, key proteins and gene expression were evaluated. Individual inhibition of each of the PIM genes did not affect PTCL cell survival, partially because of a compensatory mechanism among the three PIM genes. In contrast, pharmacological inhibition of all PIM kinases strongly induced apoptosis in all PTCL cell lines, without cell cycle arrest, in part through the induction of DNA damage. Therefore, pan-PIMi synergized with Cisplatin. Importantly, pharmacological inhibition of PIM reduced primary tumoral T cell viability without affecting normal T cells ex vivo. Since anaplastic large cell lymphoma (ALK+ ALCL) cell lines were the most sensitive to the pan-PIMi, we tested the simultaneous inhibition of ALK and PIM kinases and found a strong synergistic effect in ALK+ ALCL cell lines. Our findings suggest that PIM kinase inhibition could be of therapeutic value in a subset of PTCL, especially when combined with ALK inhibitors, and might be clinically beneficial in ALK+ ALCL.

NFκB expression is a feature of both activated B-cell-like and germinal center B-cell-like subtypes of diffuse large B-cell lymphoma.

The activation of nuclear factor kappa B (NFκB) transcription factor family is considered to have a key role in diffuse large B-cell lymphoma (DLBCL) pathogenesis and is associated with a specific molecular subtype, the activated B-cell-like (ABC) subtype. We evaluated the expression of NFκB by immunohistochemistry in a large series of DLBCL cases. The five different NFκB family members (NFκB1, NFκB2, RELA, RELB, and REL) showed a heterogeneous expression pattern with the vast majority of cases being positive for at least one factor. Two independent series of tumor samples were classified into germinal center B-cell-like (GCB) or ABC subtypes using different approaches, immunohistochemistry, or gene expression profiling, and the expression of NFκB family members was assessed. Notably, no significant differences regarding the expression of the different NFκB members were detected between the two subtypes, suggesting that NFκB signaling is a prominent feature not only in the ABC subtype, but also in the GCB tumors. Of the five transcription factors, only REL expression had a significant clinical impact on R-CHOP-treated diffuse large B-cell lymphoma, identifying a subgroup of patients with superior clinical outcome.

NIK controls classical and alternative NF-κB activation and is necessary for the survival of human T-cell lymphoma cells.

PURPOSE: Peripheral T-cell lymphomas (PTCL) are a heterogeneous entity of neoplasms with poor prognosis, a lack of effective therapies, and a largely unknown molecular pathology. Deregulated NF-κB activity has been associated with several lymphoproliferative diseases, but its importance in T-cell lymphomagenesis is poorly understood. We investigated the function of the NF-κB-inducing kinase (NIK), in this pathway and its role as a potential molecular target in T-cell lymphomas. EXPERIMENTAL DESIGN: We used immunohistochemistry to analyze the expression of different NF-κB members in primary human PTCL samples and to study its clinical impact. With the aim of inhibiting the pathway, we used genetic silencing of NIK in several T-cell lymphoma cell lines and observed its effect on downstream targets and cell viability. RESULTS: We showed that the NF-κB pathway was activated in a subset of PTCLs associated with poor overall survival. NIK was overexpressed in a number of PTCL cell lines and primary samples, and a pivotal role for NIK in the survival of these tumor cells was unveiled. NIK depletion led to a dramatic induction of apoptosis in NIK-overexpressing cell lines and also showed a more pronounced effect on cell survival than inhibitor of kappa B kinase (IKK) knockdown. NIK silencing induced a blockage of both classical and alternative NF-κB activation and reduced expression of several prosurvival and antiapoptotic factors. CONCLUSIONS: The results of the present study indicate that NIK could be a promising therapeutic target in these aggressive malignancies.

Simultaneous inhibition of pan-phosphatidylinositol-3-kinases and MEK as a potential therapeutic strategy in peripheral T-cell lymphomas.

Peripheral T-cell lymphomas are very aggressive hematologic malignancies for which there is no targeted therapy. New, rational approaches are necessary to improve the very poor outcome in these patients. Phosphatidylinositol-3-kinase is one of the most important pathways in cell survival and proliferation. We hypothesized that phosphatidylinositol-3-kinase inhibitors could be rationally selected drugs for treating peripheral T-cell lymphomas. Several phosphatidylinositol-3-kinase isoforms were inhibited genetically (using small interfering RNA) and pharmacologically (with CAL-101 and GDC-0941 compounds) in a panel of six peripheral and cutaneous T-cell lymphoma cell lines. Cell viability was measured by intracellular ATP content; apoptosis and cell cycle changes were checked by flow cytometry. Pharmacodynamic biomarkers were assessed by western blot. The PIK3CD gene, which encodes the δ isoform of phosphatidylinositol-3-kinase, was overexpressed in cell lines and primary samples, and correlated with survival pathways. However, neither genetic nor specific pharmacological inhibition of phosphatidylinositol-3-kinase δ affected cell survival. In contrast, the pan-phosphatidylinositol-3-kinase inhibitor GDC-0941 arrested all T-cell lymphoma cell lines in the G1 phase and induced apoptosis in a subset of them. We identified phospho-GSK3ß and phospho-p70S6K as potential biomarkers of phosphatidylinositol-3-kinase inhibitors. Interestingly, an increase in ERK phosphorylation was observed in some GDC -0941-treated T-cell lymphoma cell lines, suggesting the presence of a combination of phosphatidylinositol-3-kinase and MEK inhibitors. A highly synergistic effect was found between the two inhibitors, with the combination enhancing cell cycle arrest at G0/G1 in all T-cell lymphoma cell lines, and reducing cell viability in primary tumor T cells ex vivo. These results suggest that the combined treatment of pan-phosphatidylinositol-3-kinase + MEK inhibitors could be more effective than single phosphatidylinositol-3-kinase inhibitor treatment, and therefore, that this combination could be of therapeutic value for treating peripheral and cutaneous T-cell lymphomas.

EBV-positive diffuse large B-cell lymphoma of the elderly is an aggressive post-germinal center B-cell neoplasm characterized by prominent nuclear factor-kB activation.

Here, we report a retrospective series of 47 EBV-positive diffuse large B-cell lymphoma associated with advanced age. Histopathology allowed to the identification of different histological patterns: cases with polymorphic diffuse large B-cell lymphoma (29 cases), Hodgkin-like (8 cases) and polymorphic lymphoproliferative disorder-like (9 cases) patterns. One case was purely monomorphic diffuse large B-cell lymphoma. We show that this lymphoma type is a neoplasm with prominent classical and alternative nuclear factor-kB pathway activation in neoplastic cells (79% of the cases showed nuclear staining for p105/p50, 74% for p100/p52 and 63% for both proteins), with higher frequency than that observed in a control series of EBV-negative diffuse large B-cell lymphoma (χ(2) <0.001). Most cases showed an activated phenotype (95% non-germinal center (Hans algorithm); 78% activated B cell (Choi algorithm)). Clonality testing demonstrated IgH and/or K/Kde/L monoclonal rearrangements in 64% of cases and clonal T-cell populations in 24% of cases. C-MYC (1 case), BCL6 (2 cases) or IgH (3 cases) translocations were detected by FISH in 18% cases. These tumors had a poor overall survival and progression-free survival (the estimated 2-year overall survival was 40 ± 10% and the estimated 2-year progression-free survival was 36 ± 9%). Thus, alternative therapies, based on the tumor biology, need to be tested in patients with EBV-positive diffuse large B-cell lymphoma of the elderly.

Nanog regulates proliferation during early fish development.

Nanog is involved in controlling pluripotency and differentiation of stem cells in vitro. However, its function in vivo has been studied only in mouse embryos and various reports suggest that Nanog may not be required for the regulation of differentiation. To better understand endogenous Nanog function, more animal models should be introduced to complement the murine model. Here, we have identified the homolog of the mammalian Nanog gene in teleost fish and describe the endogenous expression of Ol-Nanog mRNA and protein during medaka (Oryzias latipes) embryonic development and in the adult gonads. Using medaka fish as a vertebrate model to study Nanog function, we demonstrate that Ol-Nanog is necessary for S-phase transition and proliferation in the developing embryo. Moreover, inhibition or overexpression of Ol-Nanog does not affect gene expression of various pluripotency and differentiation markers, suggesting that this transcription factor may not play a direct role in embryonic germ layer differentiation. STEM CELLS 2009;27:2081-2091.