Blood myeloid cells are known to be dysregulated in coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2. It is unknown whether the innate myeloid response differs with disease severity and ...whether markers of innate immunity discriminate high-risk patients. Thus, we performed high-dimensional flow cytometry and single-cell RNA sequencing of COVID-19 patient peripheral blood cells and detected disappearance of non-classical CD14LowCD16High monocytes, accumulation of HLA-DRLow classical monocytes (Human Leukocyte Antigen - DR isotype), and release of massive amounts of calprotectin (S100A8/S100A9) in severe cases. Immature CD10LowCD101−CXCR4+/− neutrophils with an immunosuppressive profile accumulated in the blood and lungs, suggesting emergency myelopoiesis. Finally, we show that calprotectin plasma level and a routine flow cytometry assay detecting decreased frequencies of non-classical monocytes could discriminate patients who develop a severe form of COVID-19, suggesting a predictive value that deserves prospective evaluation.
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•Patients with severe COVID-19 accumulate HLA-DRLow monocytes and immature neutrophils in blood/lungs•Calprotectin level positively correlates with neutrophil count and disease severity•Loss of non-classical monocytes could identify high risk of severe COVID-19
An analysis of patients with severe COVID-19 reveals immature neutrophil and non-classical monocyte pools, with levels of the protein calprotectin linked to disease severity.
La loi dite Pleven, adoptée le 1er juillet 1972, a permis de ne pas laisser impunies l’injure, la diffamation et la provocation à la discrimination envers une personne ou un groupe de personnes à ...raison de leur origine ou de leur appartenance ou non-appartenance à une ethnie, une nation, une race ou une religion déterminée, ce qui ne peut qu’être accueilli avec faveur. Cependant, elle a aussi conduit à la multiplication des actions engagées par des associations contre des spectacles, des expo...
Metastasis is the main cause of death for patients with breast cancer. Many studies have characterized the genomic landscape of breast cancer during its early stages. However, there is evidence that ...genomic alterations are acquired during the evolution of cancers from their early to late stages, and that the genomic landscape of early cancers is not representative of that of lethal cancers
. Here we investigated the landscape of somatic alterations in 617 metastatic breast cancers. Nine driver genes (TP53, ESR1, GATA3, KMT2C, NCOR1, AKT1, NF1, RIC8A and RB1) were more frequently mutated in metastatic breast cancers that expressed hormone receptors (oestrogen and/or progesterone receptors; HR
) but did not have high levels of HER2 (HER2
; n = 381), when compared to early breast cancers from The Cancer Genome Atlas. In addition, 18 amplicons were more frequently observed in HR
/HER2
metastatic breast cancers. These cancers showed an increase in mutational signatures S2, S3, S10, S13 and S17. Among the gene alterations that were enriched in HR
/HER2
metastatic breast cancers, mutations in TP53, RB1 and NF1, together with S10, S13 and S17, were associated with poor outcome. Metastatic triple-negative breast cancers showed an increase in the frequency of somatic biallelic loss-of-function mutations in genes related to homologous recombination DNA repair, compared to early triple-negative breast cancers (7% versus 2%). Finally, metastatic breast cancers showed an increase in mutational burden and clonal diversity compared to early breast cancers. Thus, the genomic landscape of metastatic breast cancer is enriched in clinically relevant genomic alterations and is more complex than that of early breast cancer. The identification of genomic alterations associated with poor outcome will allow earlier and better selection of patients who require the use of treatments that are still in clinical trials. The genetic complexity observed in advanced breast cancer suggests that such treatments should be introduced as early as possible in the disease course.
The tumor suppressor p53 exerts its anti-neoplastic activity primarily through the induction of apoptosis. We found that cytosolic localization of endogenous wild-type or trans-activation-deficient ...p53 was necessary and sufficient for apoptosis. p53 directly activated the proapoptotic Bcl-2 protein Bax in the absence of other proteins to permeabilize mitochondria and engage the apoptotic program. p53 also released both proapoptotic multidomain proteins and BH3-only proteins Proapoptotic Bcl-2 family proteins that share only the third Bcl-2 homology domain (BH3) that were sequestered by Bcl-xL. The transcription-independent activation of Bax by p53 occurred with similar kinetics and concentrations to those produced by activated Bid. We propose that when p53 accumulates in the cytosol, it can function analogously to the BH3-only subset of proapoptotic Bcl-2 proteins to activate Bax and trigger apoptosis.
The therapeutic efficacy of anthracyclines relies on antitumor immune responses elicited by dying cancer cells. How chemotherapy-induced cell death leads to efficient antigen presentation to T cells, ...however, remains a conundrum. We found that intratumoral CD11c+CD11b+Ly6Chi cells, which displayed some characteristics of inflammatory dendritic cells and included granulomonocytic precursors, were crucial for anthracycline-induced anticancer immune responses. ATP released by dying cancer cells recruited myeloid cells into tumors and stimulated the local differentiation of CD11c+CD11b+Ly6Chi cells. Such cells efficiently engulfed tumor antigens in situ and presented them to T lymphocytes, thus vaccinating mice, upon adoptive transfer, against a challenge with cancer cells. Manipulations preventing tumor infiltration by CD11c+CD11b+Ly6Chi cells, such as the local overexpression of ectonucleotidases, the blockade of purinergic receptors, or the neutralization of CD11b, abolished the immune system-dependent antitumor activity of anthracyclines. Our results identify a subset of tumor-infiltrating leukocytes as therapy-relevant antigen-presenting cells.
► Anthracyclines induce tumor infiltration by CD11c+CD11b+Ly6Chi DC-like cells ► DC-like cell infiltration requires the release of ATP by dying tumor cells in vivo ► DC-like cells can present tumor antigens to T cells and vaccinate mice against cancer ► DC-like cells contain myeloid precursors and ATP favors their differentiation to DCs
Several prognostic scoring systems have been proposed for chronic myelomonocytic leukemia (CMML), a disease in which some gene mutations-including ASXL1-have been associated with poor prognosis in ...univariable analyses. We developed and validated a prognostic score for overall survival (OS) based on mutational status and standard clinical variables.
We genotyped ASXL1 and up to 18 other genes including epigenetic (TET2, EZH2, IDH1, IDH2, DNMT3A), splicing (SF3B1, SRSF2, ZRSF2, U2AF1), transcription (RUNX1, NPM1, TP53), and signaling (NRAS, KRAS, CBL, JAK2, FLT3) regulators in 312 patients with CMML. Genotypes and clinical variables were included in a multivariable Cox model of OS validated by bootstrapping. A scoring system was developed using regression coefficients from this model.
ASXL1 mutations (P < .0001) and, to a lesser extent, SRSF2 (P = .03), CBL (P = .003), and IDH2 (P = .03) mutations predicted inferior OS in univariable analysis. The retained independent prognostic factors included ASXL1 mutations, age older than 65 years, WBC count greater than 15 ×10(9)/L, platelet count less than 100 ×10(9)/L, and anemia (hemoglobin < 10 g/dL in female patients, < 11g/dL in male patients). The resulting five-parameter prognostic score delineated three groups of patients with median OS not reached, 38.5 months, and 14.4 months, respectively (P < .0001), and was validated in an independent cohort of 165 patients (P < .0001).
A new prognostic score including ASXL1 status, age, hemoglobin, WBC, and platelet counts defines three groups of CMML patients with distinct outcomes. Based on concordance analysis, this score appears more discriminative than those based solely on clinical parameters.
Subtle caspase activation is associated with the differentiation of several myeloid lineages. A tightly orchestrated dance between caspase-3 activation and the chaperone HSP70 that migrates to the ...nucleus to protect the master regulator GATA-1 from cleavage transiently occurs in basophilic erythroblasts and may prepare nucleus and organelle expel that occurs at the terminal phase of erythroid differentiation. A spatially restricted activation of caspase-3 occurs in maturing megakaryocytes to promote proplatelet maturation and platelet shedding in the bloodstream. In a situation of acute platelet need, caspase-3 could be activated in response to IL-1α and promote megakaryocyte rupture. In peripheral blood monocytes, colony-stimulating factor-1 provokes the formation of a molecular platform in which caspase-8 is activated, which downregulates nuclear factor-kappa B (NF-κB) activity and activates downstream caspases whose target fragments such as those generated by nucleophosmin (NPM1) cleavage contribute to the generation of resting macrophages. Human monocytes secrete mature IL-1β in response to lipopolysaccharide through an alternative inflammasome activation that involves caspase-8, a pathway that does not lead to cell death. Finally, active caspase-3 is part of the proteases contained in secretory granules of mast cells. Many questions remain on how these proteases are activated in myeloid cell lineages, which target proteins are cleaved, whereas other are protected from proteolysis, the precise role of cleaved proteins in cell differentiation and functions, and the link between these non-apoptotic functions of caspases and the death of these diverse cell types. Better understanding of these functions may generate therapeutic strategies to control cytopenias or modulate myeloid cell functions in various pathological situations.
Chronic myelomonocytic leukemia (CMML) is a myelodysplastic syndrome/ myeloproliferative neoplasm whose diagnosis is currently based on the elevation of peripheral blood monocytes to >1 × 109/L, ...measured for ≥3 months. Diagnosis can be ambiguous; for example, with prefibrotic myelofibrosis or reactive monocytosis. We set up a multiparameter flow cytometry assay to distinguish CD14+/CD16− classical from CD14+/CD16+ intermediate and CD14low/CD16+ nonclassical monocyte subsets in peripheral blood mononucleated cells and in total blood samples. Compared with healthy donors and patients with reactive monocytosis or another hematologic malignancy, CMML patients demonstrate a characteristic increase in the fraction of CD14+/CD16− cells (cutoff value, 94.0%). The associated specificity and sensitivity values were 95.1% and 90.6% in the learning cohort (175 samples) and 94.1% and 91.9% in the validation cohort (307 samples), respectively. The accumulation of classical monocytes, which demonstrate a distinct gene expression pattern, is independent of the mutational background. Importantly, this increase disappears in patients who respond to hypomethylating agents. We conclude that an increase in the fraction of classical monocytes to >94.0% of total monocytes is a highly sensitive and specific diagnostic marker that rapidly and accurately distinguishes CMML from confounding diagnoses.
•An increase in the classical monocyte subset to >94% of total monocytes discriminates CMML from other monocytoses with high specificity.•This characteristic increase in classical monocytes disappears in CMML patients who respond to hypomethylating agents.
Loss-of-function TET2 mutations (TET2
) are frequent early clonal events in myeloid neoplasms and are thought to confer a fitness advantage to hematopoietic precursors. This large, ...multi-institutional study (n = 1084), investigated the TET2 mutational landscape and prognostic implications of the number, type, and location of TET2
and the epistatic relationship with other somatic events in chronic myelomonocytic leukemia (CMML). Nine hundred and forty-two TET2
were identified in 604 (56%) patients, of which 710 (75%) were predicted to be truncating (involving the catalytic domain). Three hundred and sixteen (29%) patients had ≥1 TET2
, with 28%, 1%, and 0.2% harboring 2, 3, and 5 mutations, respectively. In comparison to TET2
, TET2
patients were older in age, more likely to have dysplastic CMML, a higher number of co-occurring mutations, and lower-risk stratification. Importantly, TET2
were associated with a survival advantage (49 vs. 30 months, p < 0.0001), especially in the context of multiple TET2
(≥2; 57 months, p < 0.001), and truncating TET2
(51 months, p < 0.001). In addition, the adverse prognostic impact of ASXL1
was partially mitigated by concurrent TET2
, with the ASXL1
/TET2
genotype having better outcomes and resulting in further risk stratification of ASXL1 inclusive CMML prognostic models, in comparison to ASXL1
alone.
Mutations in signaling molecules of the cytokine receptor axis play a central role in myeloproliferative neoplasm (MPN) pathogenesis. Polycythemia vera is mainly related to JAK2 mutations, whereas a ...wider mutational spectrum is detected in essential thrombocythemia (ET) with mutations in JAK2, the thrombopoietin (TPO) receptor (MPL), and the calreticulin (CALR) genes. Here, we studied the mutational profile of 17 ET patients negative for JAK2V617F, MPLW515K/L, and CALR mutations, using whole-exome sequencing and next-generation sequencing (NGS) targeted on JAK2 and MPL. We found several signaling mutations including JAK2V617F at very low allele frequency, 1 homozygous SH2B3 mutation, 1 MPLS505N, 1 MPLW515R, and 2 MPLS204P mutations. In the remaining patients, 4 presented a clonal and 7 a polyclonal hematopoiesis, suggesting that certain triple-negative ETs are not MPNs. NGS on 26 additional triple-negative ETs detected only 1 MPLY591N mutation. Functional studies on MPLS204P and MPLY591N revealed that they are weak gain-of-function mutants increasing MPL signaling and conferring either TPO hypersensitivity or independence to expressing cells, but with a low efficiency. Further studies should be performed to precisely determine the frequency of MPLS204 and MPLY591 mutants in a bigger cohort of MPN.
•Enrichment of atypical MPL mutations in essential thrombocythemia.•MPLS204P and MPLY591N mutants are weak gain-of-function mutants.
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