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In patients with autoimmune pulmonary alveolar proteinosis, the use of inhaled recombinant granulocyte–macrophage colony-stimulating factor resulted in a significantly better alveolar–arterial oxygen gradient at 25 weeks than the use of placebo. The beneficial effect was not observed in smokers.

Oncolytic viruses are under development for tumor treatment. David Kirn and colleagues now report their results of a randomized phase 2 dose-finding trial of JX-594, an oncolytic immunotherapeutic vaccinia virus, in patients with advanced hepatocellular carcinoma. The study shows that high-dose JX-594 was associated with significantly improved overall survival and induced radiographic responses and antitumor immunity. Oncolytic viruses and active immunotherapeutics have complementary mechanisms of action (MOA) that are both self amplifying in tumors, yet the impact of dose on subject outcome is unclear. JX-594 (Pexa-Vec) is an oncolytic and immunotherapeutic vaccinia virus. To determine the optimal JX-594 dose in subjects with advanced hepatocellular carcinoma (HCC), we conducted a randomized phase 2 dose-finding trial ( n = 30). Radiologists infused low- or high-dose JX-594 into liver tumors (days 1, 15 and 29); infusions resulted in acute detectable intravascular JX-594 genomes. Objective intrahepatic Modified Response Evaluation Criteria in Solid Tumors (mRECIST) (15%) and Choi (62%) response rates and intrahepatic disease control (50%) were equivalent in injected and distant noninjected tumors at both doses. JX-594 replication and granulocyte-macrophage colony-stimulating factor (GM-CSF) expression preceded the induction of anticancer immunity. In contrast to tumor response rate and immune endpoints, subject survival duration was significantly related to dose (median survival of 14.1 months compared to 6.7 months on the high and low dose, respectively; hazard ratio 0.39; P = 0.020). JX-594 demonstrated oncolytic and immunotherapy MOA, tumor responses and dose-related survival in individuals with HCC.

Priming of the organ-specific premetastatic sites is thought to be an important yet incompletely understood step during metastasis. In this study, we show that the metastatic tumors we examined overexpress granulocyte-colony stimulating factor (G-CSF), which expands and mobilizes Ly6G+Ly6C+ granulocytes and facilitates their subsequent homing at distant organs even before the arrival of tumor cells. Moreover, G-CSF—mobilized Ly6G+Ly6C+ cells produce the Bv8 protein, which has been implicated in angiogenesis and mobilization of myeloid cells. Anti—G-CSF or anti-Bv8 antibodies significantly reduced lung metastasis. Transplantation of Bv8 null fetal liver cells into lethally irradiated hosts also reduced metastasis. We identified an unexpected role for Bv8: the ability to stimulate tumor cell migration through activation of one of the Bv8 receptors, prokineticin receptor (PKR)-1. Finally, we show that administration of recombinant G-CSF is sufficient to increase the numbers of Ly6G+Ly6C+ cells in organ-specific metastatic sites and results in enhanced metastatic ability of several tumors.

Myeloid-derived suppressor cells (MDSC) are induced under diverse pathologic conditions, including neoplasia, and suppress innate and adaptive immunity. While the mechanisms by which MDSC mediate immunosuppression are well-characterized, details on how they develop remain less understood. This is complicated further by the fact that MDSC comprise multiple myeloid cell types, namely monocytes and granulocytes, reflecting diverse stages of differentiation and the proportion of these subpopulations vary among different neoplastic models. Thus, it is thought that the type and quantities of inflammatory mediators generated during neoplasia dictate the composition of the resultant MDSC response. Although much interest has been devoted to monocytic MDSC biology, a fundamental gap remains in our understanding of the derivation of granulocytic MDSC. In settings of heightened granulocytic MDSC responses, we hypothesized that inappropriate production of G-CSF is a key initiator of granulocytic MDSC accumulation. We observed abundant amounts of G-CSF in vivo, which correlated with robust granulocytic MDSC responses in multiple tumor models. Using G-CSF loss- and gain-of-function approaches, we demonstrated for the first time that: 1) abrogating G-CSF production significantly diminished granulocytic MDSC accumulation and tumor growth; 2) ectopically over-expressing G-CSF in G-CSF-negative tumors significantly augmented granulocytic MDSC accumulation and tumor growth; and 3) treatment of naïve healthy mice with recombinant G-CSF protein elicited granulocytic-like MDSC remarkably similar to those induced under tumor-bearing conditions. Collectively, we demonstrated that tumor-derived G-CSF enhances tumor growth through granulocytic MDSC-dependent mechanisms. These findings provide us with novel insights into MDSC subset development and potentially new biomarkers or targets for cancer therapy.

An atypical monocyte with partial granulocyte characteristics is identified and shown to be critical for the development of fibrosis. An immunological cell type inducing liver fibrosis In this study, Shizuo Akira and colleagues identify a previously unknown monocyte–granulocyte hybrid cell type as being critical to the development of bleomycin-induced pulmonary fibrosis in mice, the most commonly used experimental study model of human lung fibrosis. The cells, termed segregated-nucleus-containing atypical monocytes (SatMs), are differentiated from committed progenitor cells under the control of the transcription factor C/EBPβ. The authors speculate that SatMs, and other reported 'disorder-specific monocyte/macrophage subtypes' corresponding to certain diseases, might be investigated as highly specific therapeutic targets. Monocytes and macrophages comprise a variety of subsets with diverse functions 1 , 2 , 3 , 4 , 5 . It is thought that these cells play a crucial role in homeostasis of peripheral organs, key immunological processes and development of various diseases. Among these diseases, fibrosis is a life-threatening disease of unknown aetiology. Its pathogenesis is poorly understood, and there are few effective therapies. The development of fibrosis is associated with activation of monocytes and macrophages 6 , 7 , 8 . However, the specific subtypes of monocytes and macrophages that are involved in fibrosis have not yet been identified. Here we show that Ceacam1 + Msr1 + Ly6C − F4/80 − Mac1 + monocytes, which we term segregated-nucleus-containing atypical monocytes (SatM), share granulocyte characteristics, are regulated by CCAAT/enhancer binding protein β (C/EBPβ), and are critical for fibrosis. Cebpb deficiency results in a complete lack of SatM. Furthermore, the development of bleomycin-induced fibrosis, but not inflammation, was prevented in chimaeric mice with Cebpb −/− haematopoietic cells. Adoptive transfer of SatM into Cebpb −/− mice resulted in fibrosis. Notably, SatM are derived from Ly6C − FcεRI + granulocyte/macrophage progenitors, and a newly identified SatM progenitor downstream of Ly6C − FcεRI + granulocyte/macrophage progenitors, but not from macrophage/dendritic-cell progenitors. Our results show that SatM are critical for fibrosis and that C/EBPβ licenses differentiation of SatM from their committed progenitor.

Sustained sepsis-associated immunosuppression is associated with uncontrolled infection, multiple organ dysfunction, and death. In the first controlled biomarker-guided immunostimulatory trial in sepsis, we tested whether granulocyte-macrophage colony-stimulating factor (GM-CSF) reverses monocyte deactivation, a hallmark of sepsis-associated immunosuppression (primary endpoint), and improves the immunological and clinical course of patients with sepsis. In a prospective, randomized, double-blind, placebo-controlled, multicenter trial, 38 patients (19/group) with severe sepsis or septic shock and sepsis-associated immunosuppression (monocytic HLA-DR [mHLA-DR] <8,000 monoclonal antibodies (mAb) per cell for 2 d) were treated with GM-CSF (4 microg/kg/d) or placebo for 8 days. The patients' clinical and immunological course was followed up for 28 days. Both groups showed comparable baseline mHLA-DR levels (5,609 +/- 3,628 vs. 5,659 +/- 3,332 mAb per cell), which significantly increased within 24 hours in the GM-CSF group. After GM-CSF treatment, mHLA-DR was normalized in 19/19 treated patients, whereas this occurred in 3/19 control subjects only (P < 0.001). GM-CSF also restored ex-vivo Toll-like receptor 2/4-induced proinflammatory monocytic cytokine production. In patients receiving GM-CSF, a shorter time of mechanical ventilation (148 +/- 103 vs. 207 +/- 58 h, P = 0.04), an improved Acute Physiology and Chronic Health Evaluation-II score (P = 0.02), and a shorter length of both intrahospital and intensive care unit stay was observed (59 +/- 33 vs. 69 +/- 46 and 41 +/- 26 vs. 52 +/- 39 d, respectively, both not significant). Side effects related to the intervention were not noted. Biomarker-guided GM-CSF therapy in sepsis is safe and effective for restoring monocytic immunocompetence. Use of GM-CSF may shorten the time of mechanical ventilation and hospital/intensive care unit stay. A multicenter trial powered for the improvement of clinical parameters and mortality as primary endpoints seems indicated. Clinical trial registered with www.clinicaltrials.gov (NCT00252915).

Although many aspects of blood production are well understood, the spatial organization of myeloid differentiation in the bone marrow remains unknown. Here we use imaging to track granulocyte/macrophage progenitor (GMP) behaviour in mice during emergency and leukaemic myelopoiesis. In the steady state, we find individual GMPs scattered throughout the bone marrow. During regeneration, we observe expanding GMP patches forming defined GMP clusters, which, in turn, locally differentiate into granulocytes. The timed release of important bone marrow niche signals (SCF, IL-1β, G-CSF, TGFβ and CXCL4) and activation of an inducible Irf8 and β-catenin progenitor self-renewal network control the transient formation of regenerating GMP clusters. In leukaemia, we show that GMP clusters are constantly produced owing to persistent activation of the self-renewal network and a lack of termination cytokines that normally restore haematopoietic stem-cell quiescence. Our results uncover a previously unrecognized dynamic behaviour of GMPs in situ , which tunes emergency myelopoiesis and is hijacked in leukaemia. During emergency myelopoiesis in mice, clusters of self-renewing granulocyte/macrophage progenitors (GMP) are transiently formed in the bone marrow cavity to produce a burst of myeloid cells; in leukaemia, GMP clusters persist and constantly generate myeloid leukaemia cells. Bone marrow's emergency blood bank During haematogenesis in the bone marrow, granulocyte/macrophage progenitors (GMPs) give rise to more differentiated granulocytes. Aurélie Hérault et al . now find that, during emergency blood generation, GMP clusters of self-renewing cells are formed, which give rise to more differentiated cells, timed through secretion of cytokines. However, during leukaemogenesis, these clusters persist and supply a constant generation of leukaemia cells. These findings provide new insights into the dynamic behaviour of GMPs.

To study the efficacy and safety of Polyethylene glycolated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) in the prevention of neutropenia during concurrent chemoradiotherapy for nasopharyngeal carcinoma (NPC). This is a single-center, prospective, randomized controlled study conducted from June 1, 2021, to October 31, 2022 on patients diagnosed with locally advanced NPC. Participants were divided into an experimental group and a control group. The experimental group received PEG-rhG-CSF injections post-chemotherapy cycles, whereas the control group received standard care without additional intervention. Outcomes assessed included grade 3/4 neutropenia incidence, blood cell count changes, febrile neutropenia rates, delays or interruptions in chemotherapy/radiotherapy due to hematological toxicity, oral mucositis incidents, and bone pain occurrences, comparing these between both groups. 1. 88 patients with locally advanced NPC were included, the incidence of grade 3 neutropenia in the experimental group was lower than that in the control group (P = 0.026); 2. The white blood cell count and neutrophil count in D7, D10, D14, and D21 in the experimental group were higher than those in the control group (P<0.01); 3. The rate of delayed chemotherapy in the experimental group was lower than that in the control group (2.3% vs. 29.5%), P = 0.001; the rate of interruption of radiotherapy in the experimental group was lower than that in the control group (2.3% vs.27.3%), P = 0.003; 4. The incidence of bone pain in the experimental group was 34.1%, of which most were mild bone pain, and no severe bone pain occurred. The leukocyte and neutrophil counts of the patients in the bone pain group were significantly higher than those of the patients in the no bone pain group, P(WBC) = 0.001, P(ANC) = 0.002. The preventive use of PEG-rhG-CSF decreases the incidence of neutropenia in patients undergoing concurrent chemoradiotherapy for NPC, thereby reducing rates of chemotherapy delays and radiotherapy interruptions, with mild adverse reactions that are tolerable by patients.

Arthritogenic alphaviruses, including chikungunya (CHIKV) and Mayaro virus (MAYV), cause disease characterized by fever, rash, and incapacitating joint pain. Alphavirus arthritis is associated with infiltration of myeloid cells and increases in several cytokines systemically, including granulocyte colony-stimulating factor (G-CSF). G-CSF is secreted by endothelial cells, fibroblasts, macrophages, and monocytes and binds to colony-stimulating factor 3 receptor (CSF3R, also known as G-CSFR) on the surface of myeloid cells. G-CSFR signaling initiates the proliferation, differentiation, and maturation of myeloid cells, especially neutrophils. Importantly, G-CSF has been found at high levels in both the acute and chronic phases of chikungunya disease; however, the role of G-CSF in arthritogenic alphavirus disease remains unexplored. Here, we sought to test the effect of G-CSF on CHIKV and MAYV infection using G-CSFR-deficient mice (G-CSFR ). Compared to wild-type mice, we observed sustained weight loss in G-CSFR mice following CHIKV and MAYV infection. Furthermore, G-CSFR mice had a significantly higher percentage of inflammatory monocytes and a reduction in neutrophils throughout infection. The difference in weight loss in G-CSFR mice induced by alphavirus infection was corrected by blocking type I IFN signaling. In summary, these studies suggest that type I IFN signaling contributes to G-CSFR-mediated control of arthritogenic alphavirus disease. Therefore, G-CSF or G-CSFR may be therapeutic targets to modulate host immune responses against arthritogenic alphavirus disease.

Background Myeloid-derived suppressor cells (MDSCs) participate in tumor-elicited immunosuppression by dramatically blocking T-cell-induced antitumor responses, thereby influencing the effectiveness of cancer immunotherapies. Treatments that alter the differentiation and function of MDSCs can partially restore antitumor immune responses. The long noncoding RNA plasmacytoma variant translocation 1 (lncRNA Pvt1) is a potential oncogene in a variety of cancer types. However, whether lncRNA Pvt1 is involved in the regulation of MDSCs has not been thoroughly elucidated to date. Methods MDSCs or granulocytic MDSCs (G-MDSCs) were isolated by microbeads and flow cytometry. Bone marrow derived G-MDSCs were induced by IL-6 and GM-CSF. The expression of lncRNA Pvt1 was measured by qRT-PCR. Specific siRNA was used to knockdown the expression of lncRNA Pvt1 in G-MDSCs. Results In this study, we found that knockdown of lncRNA Pvt1 significantly inhibited the immunosuppressive function of G-MDSCs in vitro. Additionally, lncRNA Pvt1 knockdown reduced the ability of G-MDSCs to delay tumor progression in tumor-bearing mice in vivo. Notably, lncRNA Pvt1 was upregulated by HIF-1α under hypoxia in G-MDSCs. Conclusions Taken together, our results demonstrate a critical role for lncRNA Pvt1 in regulating the immunosuppression activity of G-MDSCs, and lncRNA Pvt1 might thus be a potential antitumor immunotherapy target.