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RATIONALE: Research studies typically quantify acute respiratory exacerbation episodes (AECOPD) among people with chronic obstructive pulmonary disease (COPD) based on self-report elicited by survey questionnaire. However, AECOPD quantification by self-report could be inaccurate, potentially rendering it an imprecise tool for identification of those with exacerbation tendency. OBJECTIVE: Determine the agreement between self-reported and health records-documented quantification of AECOPD and their association with airway inflammation. METHODS: We administered a questionnaire to elicit the incidence and severity of respiratory exacerbations in the three years preceding the survey among current or former heavy smokers with or without diagnosis of COPD. We then examined electronic health records (EHR) of those with COPD and those without (tobacco-exposed persons with preserved spirometry or TEPS) to determine whether the documentation of the three-year incidence of moderate to very severe respiratory exacerbations was consistent with self-report using Kappa Interrater statistic. A subgroup of participants also underwent bronchoalveolar lavage (BAL) to quantify their airway inflammatory cells. We further used multivariable regressions analysis to estimate the association between respiratory exacerbations and BAL inflammatory cell composition with adjustment for covariates including age, sex, height, weight, smoking status (current versus former) and burden (pack-years). RESULTS: Overall, a total of 511 participants completed the questionnaire, from whom 487 had EHR available for review. Among the 222 participants with COPD (70 ± 7 years-old; 96% male; 70 ± 38 pack-years smoking; 42% current smoking), 57 (26%) reported having any moderate to very severe AECOPD (m/s-AECOPD) while 66 (30%) had EHR documentation of m/s-AECOPD. However, 42% of those with EHR-identified m/s-AECOPD had none by self-report, and 33% of those who reported m/s-AECOPD had none by EHR, suggesting only moderate agreement (Cohens Kappa = 0.47 ± 0.07; P

BACKGROUND: Endometriosis is considered as a systemic disease with the presence of proinflammatory cytokines in the circulation, which drives hypercoagulable state of endometriosis. Currently, endometriosis is classified into four stages: I (minimal), II (mild), III (moderate) and IV (severe). The aim of this study is to investigate the correlations between inflammatory markers and coagulation factors in patients diagnosed of endometriosis with stage IV. METHODS: This retrospective case-control study included 171 endometriosis patients with stage IV and 184 controls. Continuous data were expressed by mean ± standard deviation. Mann-Whitney U and χ2 tests were used to compare the medians and frequencies among the groups. Spearman analysis was conducted to determine the correlation among the measured parameters. The diagnostic values of the parameters differentiating endometriomas were tested by receiver operating characteristic (ROC) curve. RESULTS: The time of activated partial thromboplastin time (APTT) was decreased and the concentration of fibrinogen (FIB) and neutrophil-to-lymphocyte ratio (NLR) were increased in women of endometriosis with stage IV. The APTT were negatively correlated with NLR while the concentrations of FIB were positively correlated with NLR. The ROC analysis showed that the Area under the curve (AUC) of FIB was 0.766 (95% confidence interval:0.717-0.814) with sensitivity and specificity reaching 86.5 and 60.9%, respectively. The AUC of CA125 and CA199 was 0.638 (95% confidence interval: 0.578-0.697), 0.71 (95% confidence interval: 0.656-0.763) with sensitivity and specificity reaching 40.9 and 91.8%, 80.7 and 56.5% respectively. The combination of these factors showed the highest AUC of 0.895 (0.862-0.927) with sensitivity of 88.9% and specificity of 77.7%. CONCLUSION: In the present study, we found that inflammatory factors showed significant correlation with APTT or FIB in endometriosis with stage IV. Moreover, the coagulation factors combined with CA125 and CA199 were more reliable for identifying the endometriosis with stage IV.

Professional phagocytes like neutrophils and macrophages tightly control what they consume, how much they consume, and when they move after cargo uptake. We show that plasma membrane abundance is a key arbiter of these cellular behaviors. Neutrophils and macrophages lacking the G protein subunit Gβ4 exhibited profound plasma membrane expansion, accompanied by marked reduction in plasma membrane tension. These biophysical changes promoted the phagocytosis of bacteria, fungus, apoptotic corpses, and cancer cells. We also found that Gβ4-deficient neutrophils are defective in the normal inhibition of migration following cargo uptake. Sphingolipid synthesis played a central role in these phenotypes by driving plasma membrane accumulation in cells lacking Gβ4. In Gβ4 knockout mice, neutrophils not only exhibited enhanced phagocytosis of inhaled fungal conidia in the lung but also increased trafficking of engulfed pathogens to other organs. Together, these results reveal an unexpected, biophysical control mechanism central to myeloid functional decision-making.

Neutrophils are the first line of defense of the innate immune system. In response to methicillin-resistant Staphylococcus aureus infection in the skin, hematopoietic stem, and progenitor cells (HSPCs) traffic to wounds and undergo extramedullary granulopoiesis, producing neutrophils necessary to resolve the infection. This prompted the engineering of a gelatin methacrylate (GelMA) hydrogel that encapsulates HSPCs within a matrix amenable to subcutaneous delivery. The authors study the influence of hydrogel mechanical properties to produce an artificial niche for granulocyte-monocyte progenitors (GMPs) to efficiently expand into functional neutrophils that can populate infected tissue. Lin-cKIT+ HSPCs, harvested from fluorescent neutrophil reporter mice, are encapsulated in GelMA hydrogels of varying polymer concentration and UV-crosslinked to produce HSPC-laden gels of specific stiffness and mesh sizes. Softer 5% GelMA gels yield the most viable progenitors and effective cell-matrix interactions. Compared to suspension culture, 5% GelMA results in a twofold expansion of mature neutrophils that retain antimicrobial functions including degranulation, phagocytosis, and ROS production. When implanted dermally in C57BL/6J mice, luciferase-expressing neutrophils expanded in GelMA hydrogels are visualized at the site of implantation for over 5 days. They demonstrate the potential of GelMA hydrogels for delivering HSPCs directly to the site of skin infection to promote local granulopoiesis.

UNLABELLED: Gonorrhea, caused by the bacterium Neisseria gonorrhoeae (Gc), is characterized by neutrophilic influx to infection sites. Gc has developed mechanisms to resist killing by neutrophils that include modifications to its surface lipooligosaccharide (LOS). One such LOS modification is sialylation: Gc sialylates its terminal LOS sugars with cytidine-5-monophosphate-N-acetylneuraminic acid, which is scavenged from the host using LOS sialyltransferase (Lst) since Gc cannot make its sialic acid. Sialylation enables sensitive strains of Gc to resist complement-mediated killing in a serum-dependent manner. However, little is known about the contribution of sialylation to complement-independent, direct Gc-neutrophil interactions. In the absence of complement, we found sialylated Gc expressing opacity-associated (Opa) proteins decreased the oxidative burst and granule exocytosis from primary human neutrophils. In addition, sialylated Opa+ Gc survived better than vehicle treated or Δlst Gc when challenged with neutrophils. However, Gc sialylation did not significantly affect Opa-dependent association with or internalization of Gc by neutrophils. Previous studies have implicated sialic acid-binding immunoglobulin-type lectins (Siglecs) in modulating neutrophil interactions with sialylated Gc. Blocking neutrophil Siglecs with antibodies that bind to their extracellular domains eliminated the ability of sialylated Opa+ Gc to suppress the oxidative burst and resist neutrophil killing. These findings highlight a new role for sialylation in Gc evasion of human innate immunity, with implications for the development of vaccines and therapeutics for gonorrhea. IMPORTANCE: Neisseria gonorrhoeae, the bacterium that causes gonorrhea, is an urgent global health concern due to increasing infection rates, widespread antibiotic resistance, and its ability to thwart protective immune responses. The mechanisms by which Gc subverts protective immune responses remain poorly characterized. One way N. gonorrhoeae evades human immunity is by adding sialic acid that is scavenged from the host onto its lipooligosaccharide, using the sialyltransferase Lst. Here, we found that sialylation enhances N. gonorrhoeae survival from neutrophil assault and inhibits neutrophil activation, independently of the complement system. Our results implicate bacterial binding of sialic acid-binding lectins (Siglecs) on the neutrophil surface, which dampens neutrophil antimicrobial responses. This work identifies a new role for sialylation in protecting N. gonorrhoeae from cellular innate immunity, which can be targeted to enhance the human immune response in gonorrhea.

It is well established that neutrophils adopt malleable polymorphonuclear shapes to migrate through narrow interstitial tissue spaces1-3. However, how polymorphonuclear structures are assembled remains unknown4. Here we show that in neutrophil progenitors, halting loop extrusion-a motor-powered process that generates DNA loops by pulling in chromatin5-leads to the assembly of polymorphonuclear genomes. Specifically, we found that in mononuclear neutrophil progenitors, acute depletion of the loop-extrusion loading factor nipped-B-like protein (NIPBL) induced the assembly of horseshoe, banded, ringed and hypersegmented nuclear structures and led to a reduction in nuclear volume, mirroring what is observed during the differentiation of neutrophils. Depletion of NIPBL also induced cell-cycle arrest, activated a neutrophil-specific gene program and conditioned a loss of interactions across topologically associating domains to generate a chromatin architecture that resembled that of differentiated neutrophils. Removing NIPBL resulted in enrichment for mega-loops and interchromosomal hubs that contain genes associated with neutrophil-specific enhancer repertoires and an inflammatory gene program. On the basis of these observations, we propose that in neutrophil progenitors, loop-extrusion programs produce lineage-specific chromatin architectures that permit the packing of chromosomes into geometrically confined lobular structures. Our data also provide a blueprint for the assembly of polymorphonuclear structures, and point to the possibility of engineering de novo nuclear shapes to facilitate the migration of effector cells in densely populated tumorigenic environments.

In sub-Saharan Africa, multidrug-resistant non-typhoidal Salmonella serovars are a common cause of fatal bloodstream infection. Malnutrition is a predisposing factor, but the underlying mechanisms are unknown. Here we show that vitamin A deficiency, one of the most prevalent micronutrient deficits afflicting African children, increases susceptibility to disseminated non-typhoidal Salmonella disease in mice and impairs terminal neutrophil maturation. Immature neutrophils had reduced expression of Slc11a1, a gene that encodes a metal ion transporter generally thought to restrict pathogen growth in macrophages. Adoptive transfer of SLC11A1-proficient neutrophils, but not SLC11A1-deficient neutrophils, reduced systemic Salmonella burden in Slc11a1-/- mice or mice with vitamin A deficiency. Loss of terminal granulopoiesis regulator CCAAT/enhancer-binding protein ϵ (C/EBPϵ) also decreased neutrophil-mediated control of Salmonella, but not that mediated by peritoneal macrophages. Susceptibility to infection increased in Cebpe-/- Slc11a1+/+ mice compared with wild-type controls, in an Slc11a1-expression-dependent manner. These data suggest that SLC11A1 deficiency impairs Salmonella control in part by blunting neutrophil-mediated defence.

PURPOSE: Evaluate the safety and efficacy of efbemalenograstim alfa for neutrophil support in breast cancer patients undergoing myelosuppressive chemotherapy in a phase 2, dose-finding, open-label study (NCT01648322, ClinicalTrials.gov, 2012-07-19). METHODS: 232 patients received up to 4 cycles of chemotherapy, 141 patients with docetaxel + cyclophosphamide (TC) and 91 patients with docetaxel + doxorubicin + cyclophosphamide (TAC). Patients were randomized to efbemalenograstim alfa (80, 240, or 320 µg/kg [TC]; 240 or 320 µg/kg [TAC]) or pegfilgrastim (6 mg) on Day 2 of each cycle. RESULTS: Efbemalenograstim alfa was non-inferior to pegfilgrastim in duration of moderate and severe neutropenia (absolute neutrophil count [ANC]  2.0 × 109/L after the expected ANC nadir) was 2.0-2.4 and 1.9 days for TAC patients treated with efbemalenograstim alfa and pegfilgrastim, respectively. No significant difference was found between any dose of efbemalenograstim alfa and pegfilgrastim in TAC Cycle 1 for incidence of moderate to severe neutropenia (76%-77% of patients) or incidence of severe neutropenia (ANC

The chemokine CCL28 is highly expressed in mucosal tissues, but its role during infection is not well understood. Here, we show that CCL28 promotes neutrophil accumulation in the gut of mice infected with Salmonella and in the lung of mice infected with Acinetobacter. Neutrophils isolated from the infected mucosa expressed the CCL28 receptors CCR3 and, to a lesser extent, CCR10, on their surface. The functional consequences of CCL28 deficiency varied between the two infections: Ccl28-/- mice were highly susceptible to Salmonella gut infection but highly resistant to otherwise lethal Acinetobacter lung infection. In vitro, unstimulated neutrophils harbored pre-formed intracellular CCR3 that was rapidly mobilized to the cell surface following phagocytosis or inflammatory stimuli. Moreover, CCL28 stimulation enhanced neutrophil antimicrobial activity, production of reactive oxygen species, and formation of extracellular traps, all processes largely dependent on CCR3. Consistent with the different outcomes in the two infection models, neutrophil stimulation with CCL28 boosted the killing of Salmonella but not Acinetobacter. CCL28 thus plays a critical role in the immune response to mucosal pathogens by increasing neutrophil accumulation and activation, which can enhance pathogen clearance but also exacerbate disease depending on the mucosal site and the infectious agent.

BACKGROUND: Pulmonary hypertension (PH) in dogs with myxomatous mitral valve disease (MMVD) is caused by increased pulmonary venous pressure. Thrombosis, vascular remodeling, and vasoconstriction mediated by platelets could exacerbate PH. HYPOTHESIS: Dogs with PH will exhibit a hypercoagulable state, characterized by increased platelet activation, platelet-leukocyte, and platelet-neutrophil aggregate formation. ANIMALS: Eleven dogs (≥3.5 kg) diagnosed with MMVD and PH and 10 dogs with MMVD lacking PH. METHODS: Prospective cohort ex vivo study. All dogs underwent echocardiographic examination, CBC, 3-view thoracic radiographs, and heartworm antigen testing. Severity of PH and MMVD were assessed by echocardiography. Viscoelastic monitoring of coagulation was assessed using thromboelastography (TEG). Platelet activation and platelet-leukocyte/platelet-neutrophil interactions were assessed using flow cytometry. Plasma serotonin concentrations were measured by ELISA. RESULTS: Unstimulated platelets from dogs with MMVD and PH expressed more surface P-selectin than MMVD controls (P = .03). Platelets from dogs with MMVD and PH had persistent activation in response to agonists. The number of platelet-leukocyte aggregates was higher in dogs with MMVD and PH compared with MMVD controls (P = .01). Ex vivo stimulation of whole blood resulted in higher numbers of platelet-neutrophil aggregates in dogs with MMVD and PH (P = .01). Assessment of hypercoagulability based on TEG or plasma serotonin concentrations did not differ between groups. CONCLUSION AND CLINICAL IMPORTANCE: Platelet hyperresponsiveness and increased platelet-neutrophil interaction occur in dogs with MMVD and PH, suggesting that platelets play a role of in the pathogenesis of PH. Clinical benefits of antiplatelet drugs in dogs with MMVD and PH require further investigation.

BackgroundInfection with the protozoan parasite Toxoplasma gondii leads to the formation of lifelong cysts in neurons that can have devastating consequences in the immunocompromised. In the immunocompetent individual, anti-parasitic effector mechanisms and a balanced immune response characterized by pro- and anti-inflammatory cytokine production establishes an asymptomatic infection that rarely leads to neurological symptoms. Several mechanisms are known to play a role in this successful immune response in the brain including T cell production of IFNγ and IL-10 and the involvement of CNS resident cells. This limitation of clinical neuropathology during chronic infection suggests a balance between immune response and neuroprotective mechanisms that collectively prevent clinical manifestations of disease. However, how these two vital mechanisms of protection interact during chronic Toxoplasma infection remains poorly understood.Main textThis study demonstrates a previously undescribed connection between innate neutrophils found chronically in the brain, termed "chronic brain neutrophils" (CBNeuts), and neuroprotective mechanisms during Toxoplasma infection. Lack of CBNeuts during chronic infection, accomplished via systemic neutrophil depletion, led to enhanced infection and deleterious effects on neuronal regeneration and repair mechanisms in the brain. Phenotypic and transcriptomic analysis of CBNeuts identified them as distinct from peripheral neutrophils and revealed two main subsets of CBNeuts that display heterogeneity towards both classical effector and neuroprotective functions in an age-dependent manner. Further phenotypic profiling defined expression of the neuroprotective molecules NRG-1 andErbB4 by these cells, and the importance of this signaling pathway during chronic infection was demonstrated via NRG-1 treatment studies.ConclusionsIn conclusion, this work identifies CBNeuts as a heterogenous population geared towards both classical immune responses and neuroprotection during chronic Toxoplasma infection and provides the foundation for future mechanistic studies of these cells.

Acute gastrointestinal infection with intracellular pathogens like Salmonella Typhimurium triggers the release of the proinflammatory cytokine interleukin 1β (IL-1β). However, the role of IL-1β in intestinal defense against Salmonella remains unclear. Here, we show that IL-1β production is detrimental during Salmonella infection. Mice lacking IL-1β (IL-1β -/-) failed to recruit neutrophils to the gut during infection, which reduced tissue damage and prevented depletion of short-chain fatty acid (SCFA)-producing commensals. Changes in epithelial cell metabolism that typically support pathogen expansion, such as switching energy production from fatty acid oxidation to fermentation, were absent in infected IL-1β -/- mice which inhibited Salmonella expansion. Additionally, we found that IL-1β induces expression of complement anaphylatoxins and suppresses the complement-inactivator carboxypeptidase N (CPN1). Disrupting this process via IL-1β loss prevented mortality in Salmonella-infected IL-1β -/- mice. Finally, we found that IL-1β expression correlates with expression of the complement receptor in patients suffering from sepsis, but not uninfected patients and healthy individuals. Thus, Salmonella exploits IL-1β signaling to outcompete commensal microbes and establish gut colonization. Moreover, our findings identify the intersection of IL-1β signaling and the complement system as key host factors involved in controlling mortality during invasive Salmonellosis.

While the involvement of actin polymerization in cell migration is well-established, much less is known about the role of transmembrane water flow in cell motility. Here, we investigate the role of water influx in a prototypical migrating cell, the neutrophil, which undergoes rapid, directed movement to sites of injury, and infection. Chemoattractant exposure both increases cell volume and potentiates migration, but the causal link between these processes are not known. We combine single-cell volume measurements and a genome-wide CRISPR screen to identify the regulators of chemoattractant-induced neutrophil swelling, including NHE1, AE2, PI3K-gamma, and CA2. Through NHE1 inhibition in primary human neutrophils, we show that cell swelling is both necessary and sufficient for the potentiation of migration following chemoattractant stimulation. Our data demonstrate that chemoattractant-driven cell swelling complements cytoskeletal rearrangements to enhance migration speed.

Research on neutrophil biology has been limited by the short life span and limited genetic manipulability of these cells, driving the need for representative and efficient model cell lines. The promyelocytic cell line HL-60 and its subline PLB-985 can be differentiated into neutrophil-like cells (NLCs) and have been used to study neutrophil functions including chemotaxis, phagocytosis, endocytosis, and degranulation. Compared to neutrophils derived from hematopoietic stem cells, NLCs serve as a cost-effective neutrophil model. NLCs derived from both HL-60 and PLB-985 cells have been shown to perform degranulation, an important neutrophil function. However, no study has directly compared the two lines as models for degranulation including their release of different types of mobilizable organelles. Furthermore, Nutridoma, a commercially available supplement, has recently been shown to improve the chemotaxis, phagocytosis, and oxidative burst abilities of NLCs derived from promyelocytic cells, however it is unknown whether this reagent also improves the degranulation ability of NLCs. Here, we show that NLCs derived from both HL-60 and PLB-985 cells are capable of degranulating, with each showing markers for the release of multiple types of secretory organelles, including primary granules. We also show that differentiating HL-60 cells using Nutridoma does not enhance their degranulation activity over NLCs differentiated using Dimethyl Sulfoxide (DMSO) plus Granulocyte-colony stimulating factor (G-CSF). Finally, we show that promyelocytic cells can be genetically engineered and differentiated using these methods, to yield NLCs with a defect in degranulation. Our results indicate that both cell lines serve as effective models for investigating the mechanisms of neutrophil degranulation, which can advance our understanding of the roles of neutrophils in inflammation and immunity.

Gastric cancer remains a significant global health concern with poor prognosis. This study investigates the role of neutrophils in gastric cancer progression and their potential as prognostic indicators. Using multi-omics approaches, including Weighted Gene Co-expression Network Analysis (WGCNA), machine learning, and single-cell analysis, we identified neutrophil-associated gene signatures and developed a robust prognostic model. Our findings reveal distinct gastric cancer subtypes based on neutrophil-associated genes, with one subtype showing increased neutrophil infiltration and poorer prognosis. Single-cell analysis uncovered neutrophil-associated alterations in cell composition, gene expression profiles, and intercellular communication within the tumor microenvironment. Additionally, we explored the relationship between neutrophil-associated genes, microbiota composition, and alternative splicing events in gastric cancer. Furthermore, we identified QKI as a key regulator of alternative splicing and demonstrated its role in promoting malignant phenotypes and enhancing TGF-beta signaling and epithelial-mesenchymal transition in gastric cancer cells by wet experiment. Lastly, the role of QKI in the association with drug resistance and the identification of specific agents for treating QKI-associated drug resistance were also explored. This comprehensive study provides novel insights into the complex interplay between neutrophils, the tumor microenvironment, microbiota, alternative splicing and gastric cancer progression, offering potential new targets for therapeutic intervention. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Methods Results Conclusion To summarize the current knowledge of the neutrophil extracellular traps (NETs) and its critical role in various oral diseases.We reviewed the recent research on NETs through PubMed and Web of Science. An analysis of recent research results was summarized from three aspects: NETs induction and formation, functions of NETs, and NETs in oral diseases.The relationship between neutrophils and NETs is critical to the body's defense against microbial invasion. NETs can effectively combat pathogens with an anti‐inflammatory effect and meanwhile it can contribute to inflammation. Moreover, it can synergize with other immune cells to respond to stimuli, such as pathogens, host‐derived mediators, and drugs. It was revealed that NETs play different roles to influence various oral diseases like periodontitis, endodontic infection, oral mucosal diseases, maxillofacial tumors, and many other oral diseases.The balance between the protective and potentially harmful effects of NETs is a key factor in determining the outcome of infections and inflammatory responses. The role of NETs in oral diseases needs to be further studied to enable better understanding of its role in the different oral diseases. [ABSTRACT FROM AUTHOR]

Group 2 innate lymphoid cells (ILC2s) play a crucial role in allergic diseases by coordinating a complex network of various effector cell lineages involved in type 2 inflammation. However, their function in regulating airway neutrophil infiltration, a deleterious symptom of severe asthma, remains unknown. Here, we observed ILC2-dependent neutrophil accumulation in the bronchoalveolar lavage fluid (BALF) of allergic mouse models. Chromatography followed by proteomics analysis identified the alarmin high mobility group box-1 (HMGB1) in the supernatant of lung ILC2s initiated neutrophil chemotaxis. Genetic perturbation of Hmgb1 in ILC2s reduced BALF neutrophil numbers and alleviated airway inflammation. HMGB1 was loaded onto the membrane of lipid droplets (LDs) released from activated lung ILC2s. Genetic inhibition of LD accumulation in ILC2s significantly decreased extracellular HMGB1 abundance and BALF neutrophil infiltration. These findings unveil a previously uncharacterized extracellular LD-mediated immune signaling delivery pathway by which ILC2s regulate airway neutrophil infiltration during allergic inflammation. [Display omitted] • ILC2s induce airway neutrophil infiltration in asthma models • Alarmin HMGB1 secreted from ILC2s activates a neutrophil chemotaxis program • ILC2s release HMGB1-loaded lipid droplets into the extracellular milieu • Lipid droplets facilitate the intercellular delivery of alarmin signaling Whether and how ILC2s regulate airway neutrophil infiltration during asthma is unknown. Rao et al. show that ILC2s release HMGB1-loaded lipid droplets to induce neutrophil infiltration into the airway, demonstrating the crucial functions of extracellular lipid droplets in driving the pathogenic responses of ILC2s and allergic inflammation. [ABSTRACT FROM AUTHOR]

This article delves into the intricate interplay between tumors, particularly gynecologic malignancies, and neutrophil extracellular traps (NETs). The relationship between tumors, specifically gynecologic malignancies, and NETs is a multifaceted and pivotal area of study. Neutrophils, pivotal components of the immune system, are tasked with combating foreign invaders. NETs, intricate structures released by neutrophils, play a vital role in combating systemic infections but also play a role in non-infectious conditions such as inflammation, autoimmune diseases, and cancer. Cancer cells have the ability to attract neutrophils, creating tumor-associated neutrophils, which then stimulate the release of NETs into the tumor microenvironment. The impact of NETs within the tumor microenvironment is profound and intricate. They play a significant role in influencing cancer development and metastasis, as well as modulating tumor immune responses. Through the release of proteases and pro-inflammatory cytokines, NETs directly alter the behavior of tumor cells, increasing invasiveness and metastatic potential. Additionally, NETs can trigger epithelial-mesenchymal transition in tumor cells, a process associated with increased invasion and metastasis. The interaction between tumors and NETs is particularly critical in gynecologic malignancies such as ovarian, cervical, and endometrial cancer. Understanding the mechanisms through which NETs operate in these tumors can offer valuable insights for the development of targeted therapeutic interventions. Researchers are actively working towards harnessing this interaction to impede tumor progression and metastasis, opening up new avenues for future treatment modalities. As our understanding of the interplay between tumors and NETs deepens, it is anticipated that novel treatment strategies will emerge, potentially leading to improved outcomes for patients with gynecologic malignancies. This article provides a comprehensive overview of the latest research findings on the interaction between NETs and cancer, particularly in gynecologic tumors, serving as a valuable resource for future exploration in this field. [ABSTRACT FROM AUTHOR]

Rapid neutrophil recruitment is critical for controlling infection, with dysfunctional neutrophil responses in diseases like diabetes associated with greater morbidity and mortality. We have shown that the leukocyte protein ECRG4 enhances early neutrophil recruitment to cutaneous wounds and hypothesized that ECRG4 regulates the early host response to infection. Using a cutaneous infection model, we found that ECRG4 KO mice had decreased early neutrophil recruitment with persistent larger lesions, increased bacterial proliferation and systemic dissemination. Although previous work identified ECRG4 as a negative regulator of CD44 on neutrophils, the mechanism regulating neutrophil recruitment remained unknown. We demonstrated that pro-inflammatory responses were intact in ECRG4 KO mice, but found decreased neutrophil mobilization from bone marrow and decreased migration to chemokines. ECRG4 KO mouse neutrophils demonstrated an increase in adhesion molecules that regulate recruitment, including enhanced induction of integrin CD11b and increased L-selectin and CD44 on bone marrow neutrophils. Analysis of gene expression in leukocytes from diabetic patients found decreased ECRG4 expression with similar increased L-selectin and CD44. We propose a previously unrecognized mechanism governing neutrophil recruitment, whereby ECRG4 mediates neutrophil surface adhesion molecules that determine both recruitment and outside-in signaling that modulates neutrophil response to pro-inflammatory stimuli. [ABSTRACT FROM AUTHOR]

Despite the widespread adoption of emergency coronary reperfusion therapy, reperfusion‐induced myocardial injury remains a challenging issue in clinical practice. Following myocardial reperfusion, S100A8/A9 molecules are considered pivotal in initiating and regulating tissue inflammatory damage. Effectively reducing the S100A8/A9 level in ischemic myocardial tissue holds significant therapeutic value in salvaging damaged myocardium. In this study, HA (hemagglutinin)‐ and RAGE (receptor for advanced glycation end products)‐ comodified macrophage membrane‐coated siRNA nanoparticles (MMM/RNA NPs) with siRNA targeting S100A9 (S100A9‐siRNA) are successfully prepared. This nanocarrier system is able to target effectively the injured myocardium in an inflammatory environment while evading digestive damage by lysosomes. In vivo, migration of MMM/RNA NPs to myocardial injury lesions is confirmed in a myocardial ischemia‐reperfusion injury (MIRI) mouse model. Intravenous injection of MMM/RNA NPs significantly reduced S100A9 levels in serum and myocardial tissues, further decreasing myocardial infarction area and improving cardiac function. Targeted reduction of S100A8/A9 by genetically modified macrophage membrane‐coated nanoparticles may represent a new therapeutic intervention for MIRI. [ABSTRACT FROM AUTHOR]

Background: The objective was to evaluate the level of neutrophil extracellular traps (NETs) in patients with chronic kidney disease (CKD) and periodontitis, and to explore the relationship between NETs and both diseases. Methods: 63 CKD and 40 non-CKD participants were recruited and underwent periodontal examination, among which 35 early CKD patients underwent periodontal therapy. The concentrations of NETs were determined by dsDNA assay in gingival crevicular fluid (GCF) and plasma, and by flow cytometry or immunofluorescence assay in blood and gingival tissues. The correlations between NETs and clinical parameters were analyzed. The influence of periodontal therapy on periodontitis, CKD and NETs concentrations was also evaluated. Results: CKD patients had higher concentrations of NETs in plasma than non-CKD patients, and NETs concentrations were also increased in both GCF and plasma of patients with periodontitis than that of periodontally healthy patients. NETs concentrations were positively correlated with increased clinical parameters of CKD and periodontitis. The positive correlation between CKD and periodontitis was demonstrated. Moreover, periodontal therapy ameliorated periodontitis and CKD, and reduced NETs concentrations in GCF of patients. Conclusions: This study revealed that NETs might be a possible bridge between periodontitis and CKD, and suggested the potential target for therapy. [ABSTRACT FROM AUTHOR]

Old World Orthohantaviruses cause hemorrhagic fever with renal syndrome (HFRS) characterized by increased vascular permeability and acute kidney injury (AKI). Despite the systemic nature of the disease, the virus enters humans through inhalation and therefore initially encounters the immunoglobulin class A (IgA) dominated mucosal immune system. Herein, we characterized systemic IgA responses and their potential relationship to the mucosal immune activation by examining blood samples obtained from patients hospitalized due to acute Puumala orthohantavirus infection. Our findings reveal increased frequencies of putative IgA-expressing circulating mucosal-associated B1 cells and plasmablasts, as well as elevated levels of polyreactive, polymeric, virus-specific and secretory IgA in the acute stage of the disease. Importantly, the levels of circulating virus-specific and secretory IgA, as well as the putative IgA+ B1 cells, increased with the severity of AKI. Furthermore, circulating polymeric IgA displayed enhanced effector functions by forming stable complexes with the IgA receptor CD89 and induced pro-inflammatory neutrophil responses. These results suggest that excessive levels of circulating mucosal-like IgA might serve as a biomarker for HFRS disease progression. [ABSTRACT FROM AUTHOR]

Autoimmunity underlies many painful disorders, such as enthesopathies, which localize to the enthesis. From infiltration of the synovium and axial skeleton by B cells, to disturbances in the ratio of M1/M2 enthesis macrophages, to CD8 + T cell mediated inflammation, autoimmune dysregulation is becoming increasingly well characterized in enthesopathies. Tissue resident B cells, macrophages, neutrophils, and T cells have also been localized in healthy human entheses. However, the potential developmental origins, presence, and role of immune cells (ICs) in enthesis development is not known. Here, we use single-cell RNA-sequencing analysis to describe IC subtypes present in the enthesis before, during, and after mineralization, and to infer regulatory interactions between ICs and mesenchymal cells (MCs). We report the presence of nine phenotypically distinct IC subtypes, including B cells, macrophages, neutrophils, and T cells. We find that specific IC subtypes may promote MC-proliferation and differentiation, and that MCs may regulate IC phenotype and autoimmunity. Our findings suggest that bidirectional regulatory interactions between ICs and MCs may be important to enthesis mineralization, and suggest that progenitor MCs have a unique ability to limit autoimmunity during development. [ABSTRACT FROM AUTHOR]

Background: With the application of PCR testing and Metagenomic Next-Generation Sequencing(mNGS), the detection rate of causative organisms in paediatric bone and joint infections has been greatly improved. The aim of our study is to identify some indicators that could be used to distinguish the culture results to optimize the use of PCR and mNGS. Methods: In this study, a total of 117 cases of acute osteomyelitis of long bones in children who underwent pus culture were included. Patients were grouped as culture-negative (n:21) and culture-positive (n:96) groups according to the results of pus culture. Age, sex, duration of onset, maximum body temperature at onset, inflammatory indicators and D-dimer after admission were systematically collected for all patients and were compared for both groups. ROC curve (ROC) was used to evaluate the diagnostic efficiency of culture-negative. Logistic regression analysis was conducted to determine independent risk factors for culture-negative. Results: There was no significant difference in age, sex and erythrocyte sedimentation rate between culture-negative group and culture-positive group (P > 0.05). The duration of onset was longer, and the temperature, white blood cells, neutrophils count, C-reactive protein and D-dimer were less elevated in culture-negative acute osteomyelitis (P < 0.05). Duration of onset, maximum body temperature at onset, white blood cell count, neutrophil count, C-reactive protein, and D-dimer have certain diagnostic efficacy in judging the efficacy of negative culture. Logistic regression analysis indicated that the duration of onset more than 6.5 days, the maximum body temperature at onset lower than 38.35℃ and C-reactive protein lower than 78.40 mg/L were independent risk factors for negative culture (P < 0.05). Conclusions: Our study revealed that duration of onset more than 6.5 days, maximum body temperature at onset lower than 38.35℃ and C-reactive protein lower than 78.40 mg/L were independent risk factors for predicting negative culture. In children with this type of acute osteomyelitis, we recommend that the pus be tested by PCR or mNGS as a priority. [ABSTRACT FROM AUTHOR]

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia in which neutrophils play a critical role. Immune-responsive gene 1 (IRG1), responsible for itaconate production, has emerged as an important regulator of inflammation and infection, but its role during M. pneumoniae infection remains unknown. Here, we reveal that itaconate is an endogenous pro-inflammatory metabolite during M. pneumoniae infection. Irg1 knockout (KO) mice had lower levels of bacterial burden, lactate dehydrogenase (LDH), and pro-inflammatory cytokines compared with wild-type (WT) controls after M. pneumoniae infection. Neutrophils were the major cells producing itaconate during M. pneumoniae infection in mice. Neutrophil counts were positively correlated with itaconate concentrations in bronchoalveolar lavage fluid (BALF) of patients with severe M. pneumoniae pneumonia. Adoptive transfer of Irg1 KO neutrophils, or administration of β-glucan (an inhibitor of Irg1 expression), significantly attenuated M. pneumoniae pneumonia in mice. Mechanistically, itaconate impaired neutrophil bacterial killing and suppressed neutrophil apoptosis via inhibiting mitochondrial ROS. Moreover, M. pneumoniae induced Irg1 expression by activating NF-κB and STAT1 pathways involving TLR2. Our data thus identify Irg1/itaconate pathway as a potential therapeutic target for the treatment of M. pneumoniae pneumonia. Author summary: M. pneumoniae is a common human pathogen that causes community-acquired pneumonia. Neutrophil infiltration has been widely recognized as a characteristic of M. pneumoniae pneumonia; however, the interaction between neutrophils and M. pneumoniae is not completely understood. Here we demonstrate a critical role of the Irg1/itaconate metabolic pathway in neutrophils in the pathogenesis of M. pneumoniae pneumonia. We observe a positive correlation between neutrophil counts and itaconate levels in BALF from patients with severe M. pneumoniae pneumonia. We find that M. pneumoniae infection induces itaconate production in neutrophils, which dampens neutrophil bactericidal activity and impedes neutrophil apoptosis through inhibiting mitochondrial ROS (mtROS). Suppressing neutrophil itaconate production mitigates M. pneumoniae pneumonia in mice. We also find that M. pneumoniae induces Irg1 expression in neutrophils by activating NF-κB and STAT1 signaling pathways. Therefore, our findings suggest that targeting neutrophil itaconate production may be an effective therapeutic strategy for the treatment of M. pneumoniae pneumonia in humans. [ABSTRACT FROM AUTHOR]

Background: Manual therapy (MT) has been widely used in China to treat local tissue inflammation for a long time. However, there is a lack of scientific evidence for using MT in anti‐inflammatory therapy, and its anti‐inflammatory mechanism needs further clarification. Methods: We utilized MT to treat cardiotoxin (CTX) injury‐induced skeletal muscle inflammation in C57BL6/J mice. We analyzed the underlying mechanism by integrating single‐cell RNA sequencing (scRNA‐seq) with molecular techniques. Hematoxylin and eosin (H&E) and immunohistochemical (IHC) staining were used to assess skeletal muscle inflammation and muscle fiber cross‐sectional area (CSA). scRNA‐seq, immunofluorescence, and western blot were performed to determine cellular and molecular outcome changes. Results: Compared with CTX injury‐induced skeletal muscle inflammatory mice, MT intervention significantly reduced proinflammatory cytokines interleukin (IL)‐1β, IL‐6, and tumor necrosis factor alpha (TNF‐α) expression levels; scRNA‐seq detected that neutrophil numbers and activity were maximum proportions increased in injured skeletal muscle among macrophage, T cells, B cells, endothelial cells, fast muscle cells, fibroblasts, and skeletal muscle satellite cells; and S100A9 gene expression was supreme in neutrophils. However, after treatment with MT, S100A9 protein expression and the numbers and activity of Ly6g+/Mpo+ neutrophils were significantly inhibited, thus reducing the inflammatory cytokine levels and exerting an anti‐inflammatory effect by early clearing neutrophils. Conclusion: MT can mitigate localized inflammation induced by injured skeletal muscle, achieved by decreasing S100A9 protein expression and clearing neutrophils in mice, which may help advance therapeutic strategies for skeletal muscle localized inflammation. [ABSTRACT FROM AUTHOR]

Background: Acetaminophen (APAP) overdose is a significant cause of drug-induced liver injury (DILI). N-acetylcysteine (NAC) is the first-line agent used in the clinic. However, it rarely benefits patients with advanced APAP toxicity. Mesenchymal stromal cells (MSCs) have demonstrated potential in treating DILI. However, the specific mechanism by which MSCs protect against APAP-induced liver injury remains unclear. Methods: APAP was injected intraperitoneally to induce a liver injury model. We then detected histopathology, biochemical indices, and inflammatory cytokine levels to assess the efficacy of MSCs and MSC extracellular vesicles (MSC-EVs). Flow cytometry was performed to reveal the immunoregulatory effects of MSCs and MSC-EVs on the neutrophils. RNA sequencing (RNA-Seq) of liver tissues was used to identify critical target genes for MSC treatment. Results: MSC and MSC-EV treatment effectively alleviated APAP-induced liver injury and inhibited neutrophil infiltration. RNA-Seq analysis and ELISA data indicated that C-X-C motif chemokine 1 (CXCL1), a chemoattractant for neutrophils, was a key molecule in the MSC-mediated amelioration of APAP-induced liver damage. In addition, neutralization of CXCL1 reduced APAP-induced liver damage, which was accompanied by decreased neutrophil infiltration. Importantly, we verified that MSC-EV-derived miR-186-5p directly binds to the 3'-UTR of Cxcl1 to inhibit its expression in hepatocytes. The agomir miR-186-5p showed excellent potential for the treatment of DILI. Conclusions: Our findings suggest that MSCs and MSC-EVs are an effective approach to mitigate DILI. Targeting the miR-186-5p/CXCL1 axis is a promising approach to improve the efficacy of MSCs and MSC-EVs in the treatment of DILI. [ABSTRACT FROM AUTHOR]

Background: Host-related factors highly regulate the increased circulation of neutrophils during Leishmania infection. Platelet-derived Dickkopf-1 (DKK1) is established as a high-affinity ligand to LRP6. Recently, we demonstrated that DKK1 upregulates leukocyte-platelet aggregation, infiltration of neutrophils to the draining lymph node and Th2 differentiation during Leishmania infection, suggesting the potential involvement of the DKK1-LRP6 signalling pathway in neutrophil migration in infectious diseases. Results: In this study, we further explored the potential role of DKK1-LRP6 signalling in the migration and longevity of activated neutrophils in the infection site using BALB/c mice with PMNs deficient in LRP6 (LRP6NKO) or BALB/c mice deficient in both PMN LRP6 and platelet DKK1 (LRP6NKO DKK1PKO). Relative to the infected wild-type BALB/c mice, reduced neutrophil activation at the infection site of LRP6NKO or LRP6NKO DKK1PKO mice was noted. The neutrophils obtained from either infected LRP6NKO or LRP6NKO DKK1PKO mice additionally showed a high level of apoptosis. Notably, the level of LRP6 expressing neutrophils was elevated in infected BALB/c mice. Relative to infected BALB/c mice, a significant reduction in parasite load was observed in both LRP6NKO and LRP6NKO DKK1PKO infected mice. Notably, DKK1 levels were comparable in the LRP6NKO and BALB/c mice in response to infection, indicating that PMN activation is the major pathway for DKK1 in promoting parasitemia. Parasite-specific components also play a crucial role in modulating neutrophil circulation in Leishmania disease. Thus, we further determine the contribution of Leishmania membrane components in the migration of neutrophils to the infection site using null mutants deficient in LPG synthesis (Δlpg1-) or lacking all ether phospholipids (plasmalogens, LPG, and GIPLs) synthesis (Δads1-). Relative to the WT controls, Δads1- parasite-infected mice showed a sustained decrease in neutrophils and neutrophil-platelet aggregates (for at least 14 days PI), while neutrophils returned to normal in Δlpg1- parasite-infected mice after day 3 PI. Conclusion: Our results suggest that DKK1 signalling and Leishmania pathogen-associated molecular patterns appear to regulate the migration and sustenance of viable activated neutrophils in the infection site resulting in chronic type 2 cell-mediated inflammation. Created in BioRender. Ihedioha, O. (2024) BioRender.com/h48c664. [ABSTRACT FROM AUTHOR]

Objective: Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a significant pulmonary complication of RA. This study tried to elucidate the mechanisms enhancing inflammation and causing lung injury in RA-ILD, focusing on the role of neutrophil extracellular traps (NETs). The study also investigated the potential benefits of nintedanib in advanced disease. Methods: Nine RA-ILD patients and nine healthy controls were included in the study. Inflammatory markers in patients' circulation were evaluated with immunoassays. The formation of NETs was examined using a citrullinated histone H3 (CitH3) ELISA and cell immunofluorescence. Inflammatory proteins expressed in neutrophils/NETs were studied with real-time qPCR and NET ELISA. To assess the effect of nintedanib, an intracellular tyrosine kinase inhibitor with antifibrotic properties, in RA-ILD a paired study was conducted in five patients before treatment administration and 16 weeks later. Results: The soluble terminal complement complex sC5b-9 and the levels of CitH3 were significantly elevated in patients with RA-ILD, compared to healthy controls. In addition, neutrophils isolated from RA-ILD patients released NETs enriched with tissue factor and interleukin-17A. Inflammatory NETs had a dynamic role, increasing the fibrotic potential of human pulmonary fibroblasts (HPFs). On the other hand, nintedanib treatment decreased NETs and sC5b-9 levels in RA-ILD patients. Conclusion: The findings propose an interplay between circulating NETs and HPFs, establishing the immunofibrotic aspects of RA-ILD. They also support the effectiveness of nintedanib in reducing key pathological processes of the disease. Further research is needed to fully understand these mechanisms and optimize treatment strategies for RA-ILD. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) continues to be a major health concern in today's world. Despite conflictive findings, evidence supports systemic inflammation's impact on CRC patients' survival rates. Therefore, this study aims to assess the prognostic role of the innate immune system in patients with CRC. Method: A total of 449 patients were included, with a 5-year follow-up period, and absolute neutrophil counts and their related ratios were measured. Results: The non-survival group had increased levels of white blood cells, neutrophils (both p <0.001), and monocytes (p=0.038), compared to the survival group, along with other neutrophil-related ratios. We observed increased mortality risk in patients in the highest tertile of white blood cells [HR=1.85 (1.09-3.13), p<0.05], neutrophils [HR=1.78 (95% CI: 1.07-2.96), p<0.05], and monocytes [HR=2.11 (95% CI: 1.22-3.63)], compared to the lowest tertile, after adjusting for all clinicopathological variables. Random forest analysis identified neutrophils as the most crucial variable in predicting survival rates, having an AUC of 0.712, considering all clinicopathological variables. A positive relationship between neutrophil counts and metastasis was observed when neutrophil counts are considered continuous (β=0.92 (0.41), p<0.05) and tumor size (width) when neutrophils were considered as logistic variable (T1 vs T3) [OR=1.42, (95% CI: 1.05-1.98), p<0.05]. Conclusion: This study offers comprehensive insights into the immune factors that impact the prognosis of CRC, emphasizing the need for personalized prognostic tools. [ABSTRACT FROM AUTHOR]

Objective This study aimed to investigate the utility of neutrophil-related cell population data obtained by automated hematology analyzers in assessing myelodysplastic syndrome cases with decreased granules in neutrophils. Methods A total of 108 subjects were classified into normal granule (n = 35), hypogranulation (n = 37), or hypergranulation (n = 36) groups. Neutrophil cell area and granule area were measured by ImageJ. All samples were analyzed on the XR-1000 and UniCel DxH 800, and neutrophil-related parameters were compared among the 3 groups. Results Neutrophil cell area and the ratio of the granular area showed significant differences among the 3 groups; they were the highest in the hypergranulation group and lowest in the hypogranulation group. XR-1000 data showed significant differences in NE-SFL and NE-FSC among the 3 groups (P <.0001). NE-SFL and NE-FSC discriminated most accurately hypogranulation group against other groups. UniCel DxH 800 data showed significant differences in MN-V-NE, MN-MALS-N, MN-UMALS-NE, SD-UMALS-NE (P <.01), MN-LMALS-NE, and SD-LMALS-NE (P <.05) among the 3 groups. The combination of SD-V-NE and SD-LMALS-NE discriminated most accurately the hypogranulation group against the other groups. Conclusion NE-SFL and NE-FSC and the combination of SD-V-NE and SD-LMALS-NE are useful in detecting cases with decreased granules in neutrophils. [ABSTRACT FROM AUTHOR]

Reduced/deficient expression of Protein Kinase C (PKC)ζ in Cord blood (CB) T cells is associated with allergy development in children and a propensity to maintain an immature T-helper (Th)2 cytokine profile. In addition, other PKC isozymes are also low in CBTCs. Since previous studies have reported that cord blood/neonatal monocyte and neutrophil functions are significantly lower than cells from adults, it was of interest to see if the CBTC PKC levels were reflected in CB monocytes and neutrophils. Compared to adult blood, CB expresses low levels of PKCα, β2, ε, θ, μ, ζ and λ/ι in monocytes and PKCα, β2, η, θ, μ, ζ and λ/ι in neutrophils. The T-cell PKCζ levels were positively correlated with levels in CB monocytes but not in neutrophils. However, neither the monocytes nor the neutrophil PKCζ were associated with T-cell development towards a Th1 or Th2 cytokine propensity, based on the production of interferon-gamma and interleukin-4 in response to phytohemagglutinin and phorbol myristate acetate. The results demonstrate that some newborn babies display a deficiency in PKC isozymes in monocytes and neutrophils, as reported for T cells. However, unlike T cells, the PKCζ levels of the phagocytes did not correlate with regulation of development towards a Th1 or Th2 cytokine phenotype. [ABSTRACT FROM AUTHOR]

Scanning probe microscopy (SPM) is a versatile tool for studying a wide range of materials. It is well suited for investigating living matter, for example, in single-cell neutrophil studies. SPM has been extensively utilized to analyze cell physical properties, providing detailed insights into their structural and functional characteristics at the nanoscale. Its long-standing application in this field highlights its essential role in cell biology and immunology research, significantly contributing to understanding cellular mechanics and interactions. In this review, we discuss the application of SPM techniques, specifically atomic force microscopy (AFM) and scanning ion-conductance microscopy (SICM), to study the fundamental functions of neutrophils. In addition, recent advances in the application of SPM in single-cell immunology are discussed. The application of these techniques allows for obtaining data on the morphology, topography, and mechanical and electrochemical properties of neutrophils with high accuracy. [ABSTRACT FROM AUTHOR]

Simple Summary: The identification of robust prognostic biomarkers is paramount for refining cancer treatment strategies, particularly in the era of precision medicine. This systematic review and meta-analysis aim to assess the prognostic significance of the neutrophil-to-eosinophil ratio (NER) across various cancer types, with a specific focus on its correlation with OS and PFS. Pooled analyses demonstrated that elevated pretreatment NER levels were significantly associated with poorer OS and PFS. The study highlights NER as a promising and non-invasive biomarker that could help guide treatment decisions in cancer patients. However, further research is needed to confirm its potential across various cancer types and treatment settings. Background: The identification of reliable prognostic biomarkers is crucial for optimizing cancer treatment strategies, especially in the era of personalized medicine. This systematic review and meta-analysis evaluate the prognostic significance of the neutrophil-to-eosinophil ratio (NER) in various cancer types, with a focus on its association with overall survival (OS) and progression-free survival (PFS). Methods: We conducted a systematic literature search across PubMed, Scopus, and Web of Science databases for studies published up to 28 July 2024. We performed the meta-analyses with the generic inverse variance method with a random effects model and reported hazard ratios (HR) with 95% confidence intervals (CI). Results: The comprehensive literature search identified 10 studies comprising 2351 patients. Pooled analyses demonstrated that elevated pretreatment NER levels were significantly correlated with poorer OS (HR: 1.74, 95% CI: 1.28–2.36, p < 0.001) and PFS (HR: 1.53, 95% CI: 1.21–1.95, p < 0.001). Subgroup analyses confirmed a consistent adverse association between high NER and OS across various tumor types and geographic locations, although results from studies conducted in the Far East did not reach statistical significance. Conclusions: This meta-analysis demonstrates that elevated NER is associated with poorer OS and PFS in cancer patients, suggesting its potential utility as a non-invasive prognostic marker. Further validation in large, prospective studies is warranted to establish NER's role in guiding personalized treatment strategies across diverse oncologic contexts. [ABSTRACT FROM AUTHOR]

Simple Summary: Inhibitors of Bruton's tyrosine kinase (BTK) have changed how we treat chronic lymphocytic leukemia (CLL), a B cell malignancy. These inhibitors are known for blocking signals in B cells that help cancers derived from these immune cells grow, but they also have important effects on the non-malignant immune system. This work explains how BTK inhibitors influence different components of the immune system, such as B cells, T cells, and macrophages. It also reviews their impact on the generation of immune-signaling molecules or their effect on the tumor microenvironment. We also explored how these effects might be useful in treating autoimmune diseases and infections. By understanding how BTK inhibitors can impact cancer cells and the immune system, this paper highlights the potential for these drugs to be used in a wider range of medical conditions. Bruton's tyrosine kinase (BTK), a cytoplasmic tyrosine kinase, plays a pivotal role in B cell biology and function. As an essential component of the B cell receptor (BCR) signaling pathway, BTK is expressed not only in B cells but also in myeloid cells, including monocytes/macrophages, dendritic cells, neutrophils, and mast cells. BTK inhibitors (BTKis) have revolutionized the treatment of chronic lymphocytic leukemia (CLL) and other B cell malignancies. Besides their well-characterized role in inhibiting BCR signaling, BTKis also exert significant immunological influences outside the tumor cell that extend their therapeutic potential and impact on the immune system in different ways. This work elucidates the immunomodulatory mechanisms associated with BTK inhibition, focusing on CLL and other clinical contexts. We discuss how BTK inhibition affects various immune cells, including B cells, T cells, and macrophages. The effects of BTKis on the profiles of cytokines, also fundamental parts of the tumor microenvironment (TME), are summarized here as well. This review also appraises the implications of these immunomodulatory actions in the management of autoimmune diseases and infections. Summarizing the dual role of BTK inhibition in modulating malignant lymphocyte and immune cell functions, this paper highlights the broader potential clinical use of compounds targeting BTK. [ABSTRACT FROM AUTHOR]

Epidemiological studies have shown that smoking is associated with increased incidence of severe viral infections leading to hospitalization. Moreover, studies in experimental models have identified impaired antiviral responses and altered inflammatory responses, yet it is unclear how the effects of smoke exposure and influenza A infection interact and how this varies over the course of infection. We hypothesized that smoking would exacerbate innate immune responses against influenza. To test this, female BALB/c mice were exposed to cigarette smoke or air twice a day for 24–28 days and (mock) infected with H3N2 influenza A on day 21 while smoking continued. About 3 and 7 days after infection, changes in immune cell populations, the transcriptome, and viral clearance in lung tissue were analyzed. After influenza A infection, smoke-exposed mice lost significantly more weight than air-exposed controls, indicating that smoking resulted in more severe disease. Immune cell and lung tissue transcriptome analysis revealed that neutrophil infiltration was prolonged and macrophage activation dysregulated after infection of smoke-exposed mice compared with air-exposed controls. Expression of genes in IL-6 and interferon pathways was similarly longer active. In parallel, we observed slower clearance of influenza virus in smoke-exposed mice after infection compared with air-exposed controls, indicating ineffective antiviral responses. Altogether, the data from our mouse model indicate that cigarette smoke exposure prolongs innate immune responses against influenza A. The results from this study help to explain the susceptibility of current smokers to severe influenza A disease. NEW & NOTEWORTHY: In this study, we describe how cigarette smoke exposure modulates immune responses against influenza in mice over time. Using a unique model that continues smoke exposure after infection, we demonstrate that inflammation is prolonged and viral clearance is delayed. This clinically relevant model for smokers that contract influenza is well positioned to investigate interactions between smoke and influenza infection. [ABSTRACT FROM AUTHOR]

Severe asthma is a syndromic label assigned to patients based on clinical parameters, yet there are diverse underlying molecular endotypes in severe asthma pathobiology. Immunophenotyping of asthma biospecimens commonly includes a mixture of granulocytes and lymphocytes. Recently, a subset of patients with severe asthma was defined as non-type 2 with neutrophil-enriched inflammation associated with increased Th17 CD4+ T cells and IL-17 levels. Here, we used an allergen-driven mouse model of increased IL-17 and mixed granulocyte lung inflammation to determine the impact of upstream regulation by an Anticalin protein that specifically binds IL-23. Airway administration of the IL-23-binding Anticalin protein (AcIL-23) decreased lung neutrophils, eosinophils, macrophages, lymphocytes, IL-17+ CD4 T cells, mucous cell metaplasia, and methacholine-induced airway hyperresponsiveness. Selective targeting of IL-23 with a monoclonal antibody (IL-23p19; αIL-23) also decreased macrophages, IL-17+ CD4 T cells, and airway hyperresponsiveness. In contrast, a monoclonal antibody against IL-17A (αIL-17A) had no significant effect on airway hyperresponsiveness but did decrease lung neutrophils, macrophages, and IL-17+ CD4 T cells. Targeting the IL-23 pathway did not significantly change IL-5+ or IL-13+ CD4 T cells. Together, these data indicate that airway AcIL-23 mirrored the activity of systemic anti-IL-23 antibody to decrease airway hyperresponsiveness in addition to mixed granulocytic inflammation and that these protective actions were broader than blocking IL-17A or IL-5 alone, which selectively decreased airway neutrophils and eosinophils, respectively. NEW & NOTEWORTHY: This is the first report of an Anticalin protein engineered to neutralize IL-23 (AcIL-23). Airway administration of AcIL-23 in mice regulated allergen-driven airway inflammation, mucous cell metaplasia, and methacholine-induced airway hyperresponsiveness. In mixed granulocytic allergic lung inflammation, immune regulation of IL-23 was broader than neutralization of either IL-17 or IL-5. [ABSTRACT FROM AUTHOR]

Introduction Deployed military personnel may be at risk for developing acute and chronic lung disease. Prior studies of this patient population have revealed that unexplained exertional dyspnea is the most common diagnosis despite an extensive evaluation. There is a concern that an occult disorder may be affecting this population. This study evaluated the role for bronchoalveolar lavage (BAL) fluid analysis in the evaluation of chronic deployment-associated dyspnea. Materials and Methods Military personnel who reported chronic respiratory symptoms were evaluated as part of the Study of Active Duty Military for Pulmonary Disease Related to Environmental Deployment Exposures III study. Participants underwent bronchoscopy with BAL as part of a standardized evaluation. Results A total of 308 patients with a mean age of 38 ± 8.6 years underwent bronchoscopy with BAL. BAL cell-count percentages of macrophages, lymphocytes, neutrophils, and eosinophils were: 76.2 ± 17.0%, 16.3 ± 13.4%, 6.6 ± 8.9%, and 0.9 ± 3.2%, respectively. There was no clear differentiation between groups based on increases in lymphocyte counts (P  = .640), although lymphocyte values were more elevated (21.4 ± 12.1%) in the interstitial lung disease category. Neutrophil counts (6.6 ± 8.9%) were elevated compared to the reported normal reference values and were increased in the isolated pulmonary function test abnormality (9.4 ± 11.6%), large airway disorder (10.0 ± 7.5%), miscellaneous (10.9 ± 20.2%), and obstructive lung disease (11.0 ± 15.6%) groups. Eosinophil counts were within normal limits (0.9 ± 3.2%) and showed no differences between groups (P  = .545); asthma patients trended higher (1.6 ± 5.7%). BAL counts for the exertional dyspnea group were within normal reference values and showed no differences from the entire cohort. Conclusions The addition of BAL cytology did not help differentiate those patients with unexplained dyspnea from other etiologies. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the relationship between different serum oxidative markers and the delta neutrophil index and hyperemesis gravidarum. Methods: One hundred pregnant women were enrolled in the study and divided into two groups. Group 1 included 50 women with hyperemesis gravidarum, while Group 2 (control group) included 50 pregnant women similar in age, gestational week, and body mass index. Serum oxidative markers and complete blood count inflammatory markers were compared. Results: Native thiol and total thiol were significantly lower in the Group 1 when compared with the control group (P=0.029 for native thiol; P=0.035 for total thiol). Moreover, ischemia-modified albumin (IMA) and catalase values were significantly higher in the Group 1 than in the control group (P=0.023 for IMA; P=0.021 for catalase). Index1% shows the disulfide/native thiol percent ratio and means that the Group 1 oxidant load is increased but not statistically significant. Myeloperoxidase, ferroxidase, and the delta neutrophil index did not differ significantly between the two groups (P=0.591, P=0.793, and P=0.52; respectively). Conclusions: According to our study, contrary to the literature, although there are differences in some values, when evaluated individually hyperemesis gravidarum does not impose an extra burden on maternal oxidantantioxidant balance. [ABSTRACT FROM AUTHOR]

Neutrophil extracellular traps (NETs) are crucial orchestrators in wound healing, exhibiting a dual nature by providing antimicrobial properties and mediating inflammation. The interactions between NETs and skin cells, such as fibroblasts, keratinocytes, and mesenchymal stem cells (MSCs), exhibit the multifaceted impact of NETs on wound healing. Imbalanced NET-related pathways, including NF-κB, PI3K-AKT, Hippo–YAP, and Wnt/β-catenin, may result in oxidative inflammation and hinder wound healing. Integrating immune markers like interleukin (IL)-1β, IL-6, and the NET-related biomarker citrullinated histone H3 (citH3) into predictive protocols can enhance the accuracy of wound healing prognosis. Therapeutic strategies targeting NETs through small molecule inhibitors, insulin, glycoproteins, MSCs, monoclonal antibodies, and gasotransmitters are effective in wound healing. Wound healing is a complex and orchestrated process that involves hemostasis, inflammation, proliferation, and tissue remodeling. Neutrophil extracellular traps (NETs) are intricate web-like structures released by neutrophils, comprising decondensed chromatin, myeloperoxidase (MPO), and neutrophil elastase (NE), which play vital roles in regulating neutrophil-mediated immune regulation. While NETs contribute to wound healing, excessive activation induced by dysregulated inflammation can hinder the healing process. Understanding the pivotal role of NETs in wound healing and tissue remodeling, as well as their intricate interactions within the wound microenvironment, presents opportunities for innovative wound healing strategies. In this review we discuss the process of NET formation, explore the interactions between NETs and skin cells, and examine therapeutic strategies targeting NETs and drug delivery platforms to accelerate wound healing. Additionally, we discuss current clinical investigations and research challenges towards advancing wound care practices. [ABSTRACT FROM AUTHOR]

Objective Pathogenesis of antiphospholipid syndrome (APS) remains poorly elucidated. We aimed to evaluate for the first time kidney transcriptome profiles in primary APS vs systemic lupus erythematosus (SLE) and control subjects. Methods We performed RNA sequencing on archival formalin-fixed paraffin-embedded kidney biopsies from APS (n  = 4), SLE (n  = 5) and control (n  = 3) individuals, differential gene expression analysis (DGEA) and enrichment analysis using gene ontology (GO) and CORUM, KEGG and Reactome pathway databases. Results Two-dimensional projection showed a distinct gene profile in primary APS vs control kidneys samples, but similar to SLE. DGEA in APS vs controls returned 276 upregulated and 217 downregulated genes, while the comparison between APS and SLE identified 75 upregulated and 111 downregulated genes. In 276 upregulated genes, enriched GO terms were (innate) immune response, inflammatory response, leucocyte and lymphocyte activation, cytokine production and T cell activation. CORUM and KEGG revealed complement-related genes (C3, C4A, C4B). Expression levels showed logFC values of 2.25 (P  = 1.58e-05) for C3, 2.17 (P  = 2.69e-06) for C4A and 2.135 (P  = 3.7e-06) for C4B in APS vs controls, without differences between APS and SLE. Interferon (IFN) alpha/beta signalling was revealed by Reactome. Expression levels of nine IFN-regulated genes found upregulated in APS vs control kidneys (P -values ≤ 0.001 for all). Examining neutrophil-extracellular traps (NETs)-related gene expression, 13 of 15 upregulated NETs-related genes exhibited higher expression in APS vs controls but not vs SLE. Conclusion Complement, interferon and NETs-related genes are highly expressed in APS kidney tissues, similarly to SLE, pointing out the role of innate immunity in APS nephropathy pathogenesis and potential treatment targets. [ABSTRACT FROM AUTHOR]

Recent studies on viral diseases showed that neutrophils exist in various phenotypes and functional statuses, that may play a role either in viral clearance or in immunopathology. Emerging evidence suggests that dengue virus can activate neutrophils, leading to the release of myeloperoxidase and the formation of neutrophil extracellular traps; these were shown to enhance vascular permeability and mediate dengue-associated cardiac impairment, contributing to severe dengue. Neutrophils are recruited during early dengue virus infection, and they release soluble molecules such as olfactomedin 4 and soluble urokinase plasminogen activator receptor into the circulation; these may be useful biomarkers to predict disease progression in dengue. Given that neutrophils may mediate severe dengue, attenuating the neutrophil response can be an attractive pathway to ameliorate disease severity. Dengue is a mosquito-borne viral disease which causes significant morbidity and mortality each year. Previous research has proposed several mechanisms of pathogenicity that mainly involve the dengue virus and host humoral immunity. However, innate immune cells, such as neutrophils, may also play an important role in dengue, albeit a much less defined role. In this review, we discuss the emerging roles of neutrophils in dengue and their involvement in pathologies associated with severe dengue. We also describe the potential use of several neutrophil proteins as biomarkers for severe dengue. These studies suggest that neutrophils are important players in dengue, and a better understanding of neutrophil-dengue biology is urgently needed. [ABSTRACT FROM AUTHOR]

In mammalian polymorphonuclear cells, polymorphonuclear structures are assembled by loop extrusion. Mega-loop anchors and interchromosomal hubs are stabilized by nuclear condensates. Diminished loop extrusion might alter nuclear deformability. Loop extrusion programs may instruct cellular architecture. It might be feasible to engineer artificial nuclear shapes and altered nuclear deformability to manipulate immune effector cell migration. Since the cardinal discovery by Metchnikoff that neutrophils assemble into polymorphonuclear structures, insights into the mechanisms that underpin the formation of such structures have remained rudimentary. Recent studies have demonstrated that in early mammalian hematopoiesis, mononuclear versus polymorphonuclear cell fate decisions are orchestrated by intricate competitive physical forces that involve loop extrusion and phase separation programs. Changing loop extrusion programs might enable the engineering of new nuclear shapes and artificial cytoplasmic architectures in effector immune cells and beyond. Immune cell fate decisions are regulated, at least in part, by nuclear architecture. Here, we outline how nuclear architecture instructs mammalian polymorphonuclear cell differentiation. We discuss how in neutrophils loop extrusion mechanisms regulate the expression of genes involved in phagocytosis and shape nuclear morphology. We propose that diminished loop extrusion programs also orchestrate eosinophil and basophil differentiation. We portray a new model in which competitive physical forces, loop extrusion, and phase separation, instruct mononuclear versus polymorphonuclear cell fate decisions. We posit that loop extrusion programs instruct the spatial organization of cytoplasmic organelles, including neutrophil granules, mitochondria, and endoplasmic reticulum. Finally, we suggest that changing loop extrusion programs might allow the engineering of new nuclear shapes and artificial cytoplasmic architectures. [ABSTRACT FROM AUTHOR]

• In patients with kidney failure undergoing dialysis, neutrophils are dysfunctionally activated. • Plasma levels of MPO and resistin correlate with overall and cardiovascular mortality risk in kidney failure patients undergoing dialysis. • Inflammatory markers can mediate the high risk of death and CV events and can prove useful tools in risk stratification of patients undergoing dialysis. In patients with kidney failure (KF) undergoing dialysis, neutrophils are dysfunctionally activated. Such chronic activation does not correspond to increased protection against infections and is thought to cause direct vascular damage accounting for the higher incidence of cardiovascular (CV) events. We hypothesized that circulating levels of neutrophil degranulation products (i.e. myeloperoxidase (MPO) and resistin) can predict overall and CV-specific mortality in dialysis patients. MPO and resistin levels were assessed in plasma samples from n = 1182 dialysis patients who were followed-up for median 2.9 years (IQR: 1.7–4.2). Patients were 65 ± 14 (SD) years old and 36 % women. Median value of MPO and resistin were 78 ng/mL (IQR: 54 - 123) and 72 ng/mL (IQR: 46 - 110), respectively. MPO and resistin levels correlated with biomarkers of organ damage, nutritional status and inflammation. Both MPO and resistin levels predicted all-cause mortality even after adjustment for traditional risk factors and inflammation, nutritional and KF-related indexes (MPO, HR for 1 ln unit increase : 1.26, 95 %CI 1.11 – 1.42, P < 0.001; Resistin, HR for 1 ln unit increase : 1.25, 95 %CI 1.09 – 1.44, P = 0.001). Similarly, their predictive ability held true also for CV death (MPO, HR for 1 ln unit increase : 1.19, 95 %CI 1.01 – 1.41, P = 0.04; Resistin, HR for 1 ln unit increase : 1.29, 95 %CI 1.07 – 1.56, P = 0.007). Plasma levels of MPO and resistin correlate with prospective overall and CV-specific mortality risk in KF patients undergoing dialysis and might be useful prognostic tools. Mediators of inflammation may be potential target to improve survival of those patients. [ABSTRACT FROM AUTHOR]

Neutropenic sepsis (NS) is one of the leading causes of death among patients with hematologic malignancies. Identifying its predictive factors is fundamental for early detection. Few studies have evaluated the predictive factors in relation to microbial infection confirmation, which is clinically important for initiating sepsis treatment. This study aimed to determine whether selected biomarkers (i.e., body temperature, C-reactive protein, albumin, procalcitonin), treatment-related characteristics (i.e., diagnosis, duration of neutropenia, treatment modality), and infection-related characteristics (i.e., infection source, causative organisms) can predict NS in patients with hematologic malignancies. We also aimed to identify the optimal predictive cutoff points for these parameters. This retrospective case–control study used the data from a total of 163 patients (58 in the sepsis group and 105 in the non-sepsis group). We collected data with reference to the day of specimen collection, with which microbial infection was confirmed. Multiple logistic regression was used to determine predictive risk factors and the area under the curve (AUC) of the receiver operating characteristic for the optimal predictive cutoff points. The independent predictors of NS were average body temperature during a fever episode and procalcitonin level. The odds for NS rose by 9.97 times with every 1°C rise in average body temperature (95% confidence interval, CI [1.33, 75.05]) and by 2.09 times with every 1 ng/mL rise in the procalcitonin level (95% CI [1.08, 4.04]). Average body temperature (AUC = 0.77, 95% CI [0.68, 0.87]) and procalcitonin levels (AUC = 0.71, 95% CI [0.59, 0.84]) have fair accuracy for predicting NS, with the optimal cutoff points of 37.9°C and 0.55 ng/mL, respectively. This study found that average body temperature during a fever episode and procalcitonin are useful in predicting NS. Thus, nurses should carefully monitor body temperature and procalcitonin levels in patients with hematologic malignancies to detect the onset of NS. [ABSTRACT FROM AUTHOR]

Background: Periodontal diseases are chronic inflammatory conditions that require early screening for effective long‐term management. Oral neutrophil counts (ONCs) correlate with periodontal inflammation. This study investigates a point‐of‐care test using a neutrophil enzyme activity (NEA) colorimetric strip for measuring periodontal inflammation. Methods: This prospective study had two phases. Phase 1 validated the relationship between ONCs and periodontal inflammation with 90 participants. Phase 2 examined the test's applicability in a real‐world setting through a multicentre clinical trial with 375 participants at four sites. ONCs were quantified in oral rinses using laboratory‐based methods, and the NEA strip was used for ONC stratification. Clinical measures included bleeding on probing (BoP), probing depth (PD) and clinical attachment loss (CAL). Results: ONCs were significantly elevated in patients with Grade B periodontitis and deep periodontal pockets (PD ≥ 5 mm, CAL ≥ 5 mm). The NEA strip accurately classified patients into high or low ONC categories, showing 80% sensitivity, 82.5% specificity and an AUC of 0.89. It also assessed the effectiveness of periodontal therapy in reducing ONC and inflammation. The test was user‐friendly, with no reported discomfort among patients. Conclusion: The NEA strip is a user‐friendly and rapid screening tool for detecting high ONCs associated with periodontal inflammation and for evaluating the effectiveness of periodontal therapy. [ABSTRACT FROM AUTHOR]

Cancer research has become increasingly complex over the past few decades as knowledge of the heterogeneity of cancer cells, their proliferative ability, and their tumor microenvironments has become available. Although conventional therapies remain the most compelling option for cancer treatment to date, immunotherapy is a promising way to harness natural immune defenses to target and kill cancer cells. Cell-mediated drug delivery systems (CDDSs) have been an active line of research for enhancing the therapeutic efficacy and specificity of cancer immunotherapy. These systems can be tailored to different types of immune cells, allowing immune evasion and accumulation in the tumor microenvironment. By enabling the targeted delivery of therapeutic agents such as immune stimulants, cytokines, antibodies, and antigens, CDDSs have improved the survival of some patients with cancer. This review summarizes the research status of CDDSs, with a focus on their underlying mechanisms of action, biology, and clinical applications. We also discuss opportunities and challenges for implementation of CDDSs into mainstream cancer immunotherapy. Cell-mediated drug delivery systems leverage the unique biodistribution of erythrocytes, immune cells or stem cells to deliver biomolecules specifically to sites of interest, which provide a new hope for cancer therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Millions of people worldwide are affected by neurodegenerative diseases and cognitive impairment, which includes dementia, while there are only symptomatic treatments available for this syndrome at present. However, several important prospective drug targets have been identified in recent years that can potentially arrest or even reverse the progression of neurodegenerative diseases. Their natural or synthetic ligands are currently in the experimental stage of drug development. In vitro and preclinical (e.g. using animal models) studies confirm their therapeutic potential, but clinical trials often fail or produce conflicting results. Here, we first review the complexity and typology of dementia, followed by the discussion of currently available treatments, and, finally, some novel molecular and cellular approaches to this problem. [ABSTRACT FROM AUTHOR]

Neutrophils represent one of the host's first lines of defense against invading pathogens. However, an aberrant activation can cause damage to the host. In the case of respiratory infections with viral or bacterial pathogens, one of the most common complications is the development of acute respiratory distress syndrome, in which neutrophil infiltration into the lung is a hallmark. Neutrophils gain expression of chemokine receptors under inflammatory conditions, and their activation can amplify the neutrophil responses. Earlier studies showed that neutrophils recruited to the lung mucosa during bacterial infection upregulate expression of CCR3 and ex vivo stimulation of CCR3 results in an increased neutrophil activation. Therefore, the modulation of effector functions or migration of neutrophils to target sites through chemokine receptors constitutes an opportunity for pharmacological intervention. We aimed to determine whether the blockade of the CCR3 using the specific antagonist SB-328437 reduces neutrophil recruitment and inflammation in the lung in the lipopolysaccharide (LPS)-induced lung injury model and influenza infection in mice. We found that neutrophils acquire CCR3 expression in the lung alveolar space. The intraperitoneal administration of SB-328437 reduced neutrophil recruitment to the lung alveolar space and reduced tissue damage in both the LPS-induced lung injury model and influenza infection. Moreover, treatment with SB-328437 reduced the percentage of neutrophils producing TNFα and neutrophil activation in the alveolar space. Together, these data suggest that CCR3 blockade might be a pharmacological strategy to prevent the aberrant neutrophil activation that results detrimental for the host but preserves sufficient effector response to control the pathogen. [ABSTRACT FROM AUTHOR]

During recovery from septic shock, circulating mitochondrial N -formyl peptides predispose to secondary infection by occupying formyl peptide receptor 1 on the neutrophil (polymorphonuclear leukocyte) membrane, suppressing cytosolic calcium ([Ca2+]i)-dependent responses to secondarily encountered bacteria. However, no study has yet investigated therapeutic clearance of circulating mitochondrial N -formyl peptides in clinical settings. Thus, we studied how to remove mitochondrial N -formyl peptides from septic-shock plasma and whether such removal could preserve cell-surface formyl peptide receptor 1 and restore sepsis-induced polymorphonuclear leukocyte dysfunction by normalizing [Ca2+]i flux. In in vitro model systems, mitochondrial N -formyl peptide removal rescued polymorphonuclear leukocyte formyl peptide receptor 1-mediated [Ca2+]i flux and chemotaxis that had been suppressed by prior mitochondrial N -formyl peptide exposure. However, polymorphonuclear leukocyte functional recovery occurred in a stepwise fashion over 30 to 90 min. Intracellular Ca2+-calmodulin appears to contribute to this delay. In ex vivo model, systems using blood samples obtained from patients with septic shock, antimitochondrial N -formyl peptide antibodies alone failed to eliminate mitochondrial N -formyl peptides from septic-shock plasma or inhibit mitochondrial N -formyl peptide activity. We therefore created a beads-based antimitochondrial N -formyl peptide antibody cocktail by combining protein A/sepharose with antibodies specific for the most potent human mitochondrial N -formyl peptide chemoattractants. The beads-based antimitochondrial N -formyl peptide antibody cocktail treatment successfully removed those active mitochondrial N -formyl peptides from septic-shock plasma. Furthermore, the beads-based antimitochondrial N -formyl peptide antibody cocktail treatment significantly restored chemotactic and bactericidal dysfunction of polymorphonuclear leukocytes obtained from patients with septic shock who developed secondary infections. By clearing circulating mitochondrial N -formyl peptides, the immobilized antimitochondrial N -formyl peptide antibody therapy prevented mitochondrial N -formyl peptide interactions with surface formyl peptide receptor 1, thereby restoring [Ca2+]i-dependent polymorphonuclear leukocyte antimicrobial function in clinical septic-shock environments. This approach may help prevent the development of secondary, nosocomial infections in patients recovering from septic shock. [ABSTRACT FROM AUTHOR]