Mechanisms regulating neutrophil responses in immunity, allergy, and autoimmunity

Oral health management in children with severe congenital neutropenia with periodontitis: Case report

RATIONALE

Severe congenital neutropenia (SCN) is a rare and heterogeneous genetic disease. By describing the diagnosis and treatment of a child with SCN and periodontitis, this case provides a reference for the oral health management of a child with SCN and periodontitis.

PATIENT CONCERNS

We describe a boy with clinical manifestations of oral bleeding, neutropenia, recurrent fever, and other recurrent infections. The absolute neutrophil count (ANC) was <0.50 × 109/L most of the time. Morphological examination of bone marrow cells showed active granulocyte hyperplasia and dysmaturation.

DIAGNOSES

According to the clinical manifestations, hematological examination and gene detection results, the child was diagnosed as SCN with chronic periodontitis.

INTERVENTIONS

Periodontal treatment was performed after informed consent was obtained from the child guardian. These included supragingival and subgingival cleaning, hydrogen peroxide and saline irrigation, placement of iodoglycerin in the gingival sulcus, and oral hygiene instruction. Hematopoietic stem cell transplantation (HSCT) was performed later.

OUTCOMES

One month after initial periodontal treatment, oral hygiene was well maintained and gingival swelling had subsided. Probing depth (PD) index on periodontal probing and bleeding was significantly reduced. However, there was no significant change in blood routine and other indicators before and after periodontal treatment.

CONCLUSION

Once SCN is diagnosed, individualized treatment plans can be developed according to the characteristics of the disease and its impact on oral health, which can effectively control the interaction between SCN and periodontal disease and reduce the occurrence of serious infection.

Histone lactylation-ROS loop contributes to light exposure-exacerbated neutrophil recruitment in zebrafish

Light serves as a crucial external zeitgeber for maintaining and restoring physiological homeostasis in most organisms. Disrupting of light rhythms often leads to abnormal immune function, characterized by excessive inflammatory responses. However, the underlying regulatory mechanisms behind this phenomenon remain unclear. To address this concern, we use in vivo imaging to establish inflammation models in zebrafish, allowing us to investigate the effects and underlying mechanisms of light disruption on neutrophil recruitment. Our findings reveal that under sustained light conditions (LL), neutrophil recruitment in response to caudal fin injury and otic vesicle inflammation is significantly increased. This is accompanied by elevated levels of histone (H3K18) lactylation and reactive oxygen species (ROS) content. Through ChIP-sequencing and ChIP‒qPCR analysis, we discover that H3K18 lactylation regulates the transcriptional activation of the duox gene, leading to ROS production. In turn, ROS further promote H3K18 lactylation, forming a positive feedback loop. This loop, driven by H3K18 lactylation-ROS, ultimately results in the over recruitment of neutrophils to inflammatory sites in LL conditions. Collectively, our study provides evidence of a mutual loop between histone lactylation and ROS, exacerbating neutrophil recruitment in light disorder conditions, emphasizing the significance of maintaining a proper light-dark cycle to optimize immune function.

Linkage of serum ITIH4 with Th2 signature cytokine, inflammation, exacerbation risk and severity in childhood asthma

Aim: ITIH4 has anti-inflammatory properties toward eosinophilic/neutrophilic inflammation. This study aimed to explore clinical value of ITIH4 in childhood asthma. Materials & methods: Serum ITIH4 and inflammatory cytokines were determined in 120 childhood asthma patients by enzyme-linked immunosorbent assay. Results: In the entire and acute exacerbation patients, ITIH4 positively associated with IFN-γ, but negatively related to proinflammatory cytokines. ITIH4 was lowest in patients with acute exacerbation, followed by chronic persistent, and highest in clinical remission. By receiver-operating characteristic analysis, ITIH4 potentially estimated acute exacerbation asthma risk. Moreover, ITIH4 negatively related to exacerbation severity in acute exacerbation patients. Conclusion: Serum ITIH4 negatively links with Th2 cell signature cytokine, proinflammatory cytokines, exacerbation risk and severity in childhood asthma.

Extracellular adenosine triphosphate skews the T helper cell balance and enhances neutrophil activation in mice with food allergies

Exposure to food allergens elicits fast changes in the intestinal microenvironment, which guides the development of allergic reactions. Investigating the key information about these changes may help in better understanding food allergies. In this research, we explored the relationship between a food allergy and extracellular adenosine triphosphate (ATP), a danger molecule that has been proved to regulate the onset of allergic asthma and dermatitis but has not been studied in food allergies, by developing a unique animal model through allergen-containing diet feeding. After consuming an allergen-containing diet for 7 days, the allergic mice exhibited severe enteritis with elevated luminal ATP levels. The dysregulated luminal ATP worsened food-induced enteritis by enhancing Th17 cell responses and increasing mucosal neutrophil accumulation. In vitro experiments demonstrated that ATP intervention facilitated Th17 cell differentiation and neutrophil activation. In addition, the diet-induced allergy showed noticeable gut dysbiosis, characterized by decreased microbial diversity and increased diet-specific microbiota signatures. As the first, we show that food-induced enteritis is associated with an elevated concentration of luminal ATP. The dysregulated extracellular ATP exacerbated the enteritis of mice to a food challenge by manipulating intestinal Th17 cells and neutrophils.

Immunosuppressive Ability of Trichinella spiralis Adults Can Ameliorate Type 2 Inflammation in a Murine Allergy Model

BACKGROUND

There is an increase in the global incidence of allergies. The hygiene hypothesis and the old friend hypothesis reveal that helminths are associated with the prevalence of allergic diseases. The therapeutic potential of Trichinella spiralis is recognized; however, the stage at which it exerts its immunomodulatory effect is unclear.

METHODS

We evaluated the differentiation of bone marrow-derived macrophages stimulated with T spiralis excretory-secretory products. Based on an ovalbumin-induced murine model, T spiralis was introduced during 3 allergy phases. Cytokine levels and immune cell subsets in the lung, spleen, and peritoneal cavity were assessed.

RESULTS

We found that T spiralis infection reduced lung inflammation, increased anti-inflammatory cytokines, and decreased Th2 cytokines and alarms. Recruitment of eosinophils, CD11b+ dendritic cells, and interstitial macrophages to the lung was significantly suppressed, whereas Treg cells and alternatively activated macrophages increased in T spiralis infection groups vs the ovalbumin group. Notably, when T spiralis was infected prior to ovalbumin challenge, intestinal adults promoted proportions of CD103+ dendritic cells and alveolar macrophages.

CONCLUSIONS

T spiralis strongly suppressed type 2 inflammation, and adults maintained lung immune homeostasis.

Associations of serum carotenoids with asthma and mortality in the US adults

Objective

This study was to investigate the association between serum carotenoid levels and the prevalence of asthma, as well as the relationship between serum carotenoid levels and the risk of mortality among individuals with asthma.

Methods

Data on five serum carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, and lycopene) were obtained from the National Health and Nutrition Examination Survey (NHANES) 2001-2006. Mortality data was extracted from the pertinent mortality records within the NHANES database, up to December 31, 2019. Logistic regression analysis was employed to investigate the association between serum carotenoid concentrations and asthma prevalence. Cox proportional hazards models were used to investigate the connection between serum carotenoids and mortality rates in asthma individuals.

Results

Among the study population, 1569 (12.63 %) individuals were diagnosed with asthma, while 25.01 % of asthma patients died within a median follow-up duration of 15.5 (13.8-17.3) years. After controlling for all other variables, greater serum levels of certain carotenoids, such asα-carotene, β-carotene, β-cryptoxanthin, and lutein/zeaxanthin, were found to be substantially linked with a decreased prevalence of asthma. Furthermore, persons with asthma who had greater levels of serum carotenoids in the fourth quartile had a significantly lower risk of all-cause death compared to those in the first quartile. Specifically, the presence of α-carotene, β-cryptoxanthin, and lutein/zeaxanthin was associated with reductions in all-cause mortality by 45 % (HR = 0.55 [0.36-0.84], Ptrend = 0.002), 38 % (HR = 0.62 [0.42-0.92], Ptrend = 0.004), and 45 % (HR = 0.55 [0.41-0.73], Ptrend<0.001), respectively. The above relationships are mostly linear and remain robust in sensitivity analyses.

Conclusions

Our findings indicate that higher serum carotenoids are related with a reduced likelihood of mortality in asthmatic individuals.

Identification of CXC Chemokine Receptor 2 (CXCR2) as a Novel Eosinophils-Independent Diagnostic Biomarker of Pediatric Eosinophilic Esophagitis by Integrated Bioinformatic and Machine-Learning Analysis

Background

Eosinophilic esophagitis (EoE) is a complex allergic condition frequently accompanied by various atopic comorbidities in children, which significantly affects their life qualities. Therefore, this study aimed to evaluate pivotal molecular markers that may facilitate the diagnosis of EoE in pediatric patients.

Methods

Three available EoE-associated gene expression datasets in children: GSE184182, GSE 197702, GSE55794, along with GSE173895 were downloaded from the GEO database. Differentially expressed genes (DEGs) identified by "limma" were intersected with key module genes identified by weighted gene co-expression network analysis (WGCNA), and the shared genes went through functional enrichment analysis. The protein-protein interaction (PPI) network and the machine learning algorithms: least absolute shrinkage and selection operator (LASSO), random forest (RF), and XGBoost were used to reveal candidate diagnostic markers for EoE. The receiver operating characteristic (ROC) curve showed the efficacy of differential diagnosis of this marker, along with online databases predicting its molecular regulatory network. Finally, we performed gene set enrichment analysis (GSEA) and assessed immune cell infiltration of EoE/control samples by using the CIBERSORT algorithm. The correlations between the key diagnostic biomarker and immune cells were also investigated.

Results

The intersection of 936 DEGs and 1446 key module genes in EoE generated 567 genes, which were primarily enriched in immune regulation. Following the construction of the PPI network and filtration by machine learning, CXCR2 served as a potential diagnostic biomarker of pediatric EoE with a perfect diagnostic efficacy (AUC = ~1.00) in regional tissue/peripheral whole blood samples. Multiple infiltrated immune cells were observed to participate in disrupting the homeostasis of esophageal epithelium to varying degrees.

Conclusion

The immune-correlated CXCR2 gene was proved to be a promising diagnostic indicator for EoE, and dysregulated regulatory T cells (Tregs)/neutrophils might play a crucial role in the pathogenesis of EoE in children.

The Role of Neutrophils in ANCA-Associated Vasculitis: The Pathogenic Role and Diagnostic Utility of Autoantibodies

Recent years have brought progress in understanding the role of the neutrophil, dispelling the dogma of homogeneous cells mainly involved in the prime defence against pathogens, shedding light on their pathogenic role in inflammatory diseases and on the importance of antineutrophil-cytoplasmic antibodies' pathogenic role in ANCA-associated vasculitides vasculitis (AAV). Myeloperoxidase (MPO) and proteinase 3 (PR3) expressed in neutrophil granulocytes are the most common targets for ANCAs and contribute to the formation of MPO-ANCAs and PR3-ANCAs which, released to the bloodstream, become an excellent diagnostic tool for AAV. In this study, we focus on increasing the clinical and experimental evidence that supports the pathogenic role of ANCAs in AAV. Additionally, we discuss the diagnostic utility of ANCAs for disease activity and prognosis in AAV. Understanding the central role of ANCAs in AAV is crucial for advancing our knowledge of these complex disorders and developing targeted therapeutic strategies in the era of personalized medicine.

ATP functions as a primary alarmin in allergen-induced type 2 immunity

Environmental allergens that interact with the airway epithelium can activate cellular stress pathways that lead to the release of danger signals known as alarmins. The mechanisms of alarmin release are distinct from damage-associated molecular patterns (DAMPs), which typically escape from cells after loss of plasma membrane integrity. Oxidative stress represents a form of allergen-induced cellular stress that stimulates oxidant-sensing mechanisms coupled to pathways, which facilitate alarmin mobilization and efflux across the plasma membrane. In this review, we highlight examples of alarmin release and discuss their roles in the initiation of type 2 immunity and allergic airway inflammation. In addition, we discuss the concept of alarmin amplification, where "primary" alarmins, which are directly released in response to a specific cellular stress, stimulate additional signaling pathways that lead to secretion of "secondary" alarmins that include proinflammatory cytokines, such as IL-33, as well as genomic and mitochondrial DNA that coordinate or amplify type 2 immunity. Accordingly, allergen-evoked cellular stress can elicit a hierarchy of alarmin signaling responses from the airway epithelium that trigger local innate immune reactions, impact adaptive immunity, and exacerbate diseases including asthma and other chronic inflammatory conditions that affect airway function.

The Combination of R848 with Sorafenib Enhances Antitumor Effects by Reprogramming the Tumor Immune Microenvironment and Facilitating Vascular Normalization in Hepatocellular Carcinoma

Novel promising strategies for combination with sorafenib are urgently needed to enhance its clinical benefit and overcome toxicity in hepatocellular carcinoma (HCC). the molecular and immunomodulatory antitumor effects of sorafenib alone and in combination with the new immunotherapeutic agent R848 are presented. Syngeneic HCC mouse model is presented to explore the antitumor effect and safety of three sorafenib doses alone, R848 alone, or their combination in vivo. R848 significantly enhances the sorafenib antitumor activity at a low subclinical dose with no obvious toxic side effects. Furthermore, the combination therapy reprograms the tumor immune microenvironment by increasing antitumor macrophages and neutrophils and preventing immunosuppressive signaling. Combination treatment promotes classical M1 macrophage-to-FTH1high M1 macrophage transition. The close interaction between neutrophils/classical M1 macrophages and dendritic cells promotes tumor antigen presentation to T cells, inducing cytotoxic CD8+ T cell-mediated antitumor immunity. Additionally, low-dose sorafenib, alone or combined with R848, normalizes the tumor vasculature, generating a positive feedback loop to support the antitumor immune environment. Therefore, the combination therapy reprograms the HCC immune microenvironment and normalizes the vasculature, improving the therapeutic benefit of low-dose sorafenib and minimizing toxicity, suggesting a promising novel immunotherapy (R848) and targeted therapy (tyrosine kinase inhibitors) combination strategy for HCC treatment.

The circadian neutrophil, inside-out

The circadian clock has sway on a myriad of physiological targets, among which the immune and inflammatory systems are particularly prominent. In this review, we discuss how neutrophils, the wildcard of the immune system, are regulated by circadian oscillations. We describe cell-intrinsic and extrinsic diurnal mechanisms governing the general physiology and function of these cells, from purely immune to homeostatic. Repurposing the concepts discovered in other cell types, we then speculate on various uncharted avenues of neutrophil-circadian relationships, such as topology, metabolism, and the regulation of tissue clocks, with the hope of identifying exciting new avenues of work in the context of circadian immunity.

Profiles of immune infiltration in seasonal allergic rhinitis and related genes and pathways

BACKGROUND

Seasonal allergic rhinitis (SAR) is a chronic inflammatory disease for which the molecular mechanism is unclear.

METHODS

Whole blood, CD4⁺ T cells in peripheral blood mononuclear cells (PBMCs), and CD4⁺ T cells in nasal mucosa from SAR-related datasets (GSE43497, GSE50223, and GSE49782) were downloaded from the Gene Expression Omnibus (GEO) database. Differences in SAR-associated immune cell infiltration in the PBMCs were analyzed using the CIBERSORT algorithm. Differential gene expression analysis was conducted between different groups. Gene set enrichment analysis (GSEA) was performed using the clusterProfiler package to explore functional changes in signaling pathways.

RESULTS

There was a significant increase in the proportion of CD8⁺ T cells and a significant decrease in the proportion of neutrophils in the whole blood of SAR patients after allergen challenge compared to SAR patients after diluent challenge. This pattern was also found in SAR patients compared to healthy controls (HCs) by flow cytometry. The NF-κB and Toll-like receptor signaling pathways were enriched in SAR patients following allergen challenge. The expression of CD4⁺ T cell marker genes and associated cytokines significantly differed between allergen-treated SAR patients, diluent-treated SAR patients and HCs. We also observed heightened CD4⁺ T cell related genes, cytokines and pathways activation in the nasal mucosa region of SAR patients after allergen challenge.

CONCLUSION

Our analysis revealed that T cell receptor signaling pathways, T helper 1 (Th1) /T helper 2 (Th2) cell differentiation may contribute to the development of SAR. The present study is the first bioinformatic analysis to quantify immune cell infiltration and identify underlying SAR mechanisms from combined microarray data and provides insight for further research into the molecular mechanisms of SAR.

Anti-inflammatory and antiviral activities of flavone C-glycosides of Lophatherum gracile for COVID-19

Lophatherum gracile (L. gracile) has long been used as a functional food and herbal medicine. Previous studies have demonstrated that extracts of L. gracile attenuate inflammatory response and inhibit SARS-CoV-2 replication; however, the underlying active constituents have yet to be identified. This study investigated the bioactive components of L. gracile. Flavone C-glycosides of L. gracile were found to dominate both anti-inflammatory and antiviral effects. A simple chromatography-based method was developed to obtain flavone C-glycoside-enriched extract (FlavoLG) from L. gracile. FlavoLG and its major flavone C-glycoside isoorientin were shown to restrict respiratory bursts and the formation of neutrophil extracellular traps in activated human neutrophils. FlavoLG and isoorientin were also shown to inhibit SARS-CoV-2 pseudovirus infection by interfering with the binding of the SARS-CoV-2 spike on ACE2. These results provide scientific evidence indicating the efficacy of L. gracile as a potential supplement for treating neutrophil-associated COVID-19.

Immunological Parameters in Patients Suffering from Atopic Dermatitis and Either Treated or Non-Treated with Dupilumab

OBJECTIVE

The aim of the study is to analyze the absolute count of leukocytes, neutrophils, monocytes, eosinophils, T cells, natural killer cells, B cells and to evaluate the expression of functionally important CD23 and CD200 molecules on B cells in patients suffering from atopic dermatitis (AD), (with and without dupilumab therapy).

MATERIALS AND METHODS

We examined 45 patients suffering from AD - 32 patients without dupilumab treatment (10 men, 22 women, average age 35.0 years), 13 patients with dupilumab treatment (7 men, 6 women, average age 43.4 years) and 30 healthy control (10 men, 20 women, average age 44.7 years). Immunophenotype was examined by flow cytometry (Navios Flow Cytometer - Beckman Coulter). The blood count was examined with a Sysmex XN 3000, Sysmex SP10, microscope DI60 for digital morphology evaluating cell division and microscope Olympus BX40. We compared the absolute count of leukocytes and their subsets, T cells (CD4, CD8), natural killers cells, absolute and relative count of B lymphocytes and expression of surface molecules CD23 and CD200 on B cells in AD patients and in control group. Non-parametric Kruskal-Wallis one-factor analysis of variance with post-hoc (follow-up multiple comparison) and Dunn's test with Bonferroni modification of significance level were used for statistical analysis.

RESULTS

We confirmed the significantly higher number of neutrophils, monocytes and eosinophils and higher expression of CD23 and CD200 on B cells in peripheral blood of AD patients (either with or without dupilumab) therapy. We demonstrated the lower number of CD8+ T cells.

CONCLUSION

We demonstrated the difference in the count of white blood cells populations in patients suffering from AD compared with healthy control. There were a differences in the expression of immunoregulatory molecules CD23 and CD200 on B cells in AD patients (either with or without dupilumab therapy) in comparison to healthy controls.