Eosinophils from Physiology to Disease: A Comprehensive Review

Disease Overlap, Healthcare Resource Utilization, and Costs in Patients with Eosinophilic Granulomatosis with Polyangiitis: A REVEAL Sub-study

INTRODUCTION

Eosinophilic granulomatosis with polyangiitis (EGPA) is an eosinophil-associated disease (EAD) characterized by inflammation in small- to medium-sized blood vessels. In the REal-world inVestigation of Eosinophilic-Associated disease overLap (REVEAL) study, overlap among 11 EADs was assessed. In the present sub-study, we evaluated EGPA overlap with other EADs, all-cause EAD- and EGPA-related healthcare resource utilization (HCRU) and costs, and their relationship with blood eosinophil count and treatments received.

METHODS

REVEAL, a retrospective study, used Optum's de-identified Clinformatics® Data Mart Database. In this sub-study, eligibility criteria included an age of ≥ 12 years, ≥ 1 EAD, continuous health-plan eligibility, and compliance with the EGPA/GPA case definition per International Classification of Diseases Ninth/Tenth Revision diagnostic codes between 1 January 2015 and 30 June 2018. Patients were grouped based on whether they had received immunomodulators/cyclophosphamide/mepolizumab (ICM) or not (non-ICM).

RESULTS

Of 701 patients with EGPA, 29.5% were in the ICM group. Overall, 72.2% had ≥ 1 overlapping EAD. The number of overlaps was similar for the ICM and non-ICM groups. In patients with blood eosinophil counts ≥ 300 cells/µL, 22.8% had ≥ 1 overlapping EAD. The mean annual all-cause cost was $98,644, 54.1% of which was from outpatients and 33.6% from inpatients. The mean annual EAD- and EGPA-related costs were $23,820 and $9,306, respectively. Patients in the non-ICM group versus the ICM group had higher all-cause ($101,560 vs $91,684) but lower EAD-related ($22,733 vs $26,412) and EGPA-related ($6,171 vs $16,786) costs. All-cause HCRU and costs increased with increasing overlap.

CONCLUSIONS

EGPA was associated with substantial HCRU and costs, driven by outpatient and inpatient settings. More overlapping EADs were associated with higher HCRU and costs, highlighting the need for treatment to reduce healthcare expenditure in these patients. Infographic available for this article.

Prediction of Postoperative Recurrence of Chronic Subdural Hematoma Using Preoperative Systemic Immune Inflammation Index and Eosinophils

Objective  Chronic subdural hematoma (CSDH) is a common neurological problem with significant recurrence after surgery. Risk considerations can vary, ranging from patient-related factors to those related to the surgical procedure. This study explores the association between preoperative eosinophil count and systemic immune inflammation (SII) with CSDH recurrence. Materials and Methods  We conducted a prospective analysis of 105 patients with equal numbers of CSDHs who underwent surgery for CSDH between January 2023 and January 2024. The preoperative eosinophil counts, along with other differential leukocyte counts, were measured. The SII index was calculated using the standard formula (SII = neutrophil count  ×  platelet count/lymphocyte count). Multivariate and univariate regression analyses were performed to assess the association between risk factors and CSDH recurrence. Results  The preoperative eosinophil count showed a significant correlation with recurrence ( p  < 0.001). The SII index was significantly higher in patients with recurrent CSDH ( p  = 0.003). Neutrophils were found to be significantly associated with CSDH recurrence ( p  = 0.038). Age ( p  < 0.001) and SII ( p  = 0.005) were found to be independent predictors of CSDH recurrence, whereas hematoma volume ( p  < 0.001) and the antiplatelet regimen were a significant predictor of CSDH recurrence ( p  = 0.047). Variables like male gender, diabetes mellitus, anticoagulants, and hematoma volume were associated with eosinophil-rich or eosinophil-poor status. Conclusion  Preoperative eosinophil count, neutrophils, and the SII index may serve as potential predictors of CSDH recurrence. Further studies with larger sample sizes are needed to validate these findings.

Ten clinical conundrums in the management of eosinophilic granulomatosis with polyangiitis

INTRODUCTION

Eosinophilic granulomatosis with polyangiitis (EGPA) is an immune-mediated, inflammatory, multisystemic disease that is considered a form of ANCA-associated vasculitis and whose association with asthma and blood and tissue eosinophilia differentiate it from other types of vasculitis. Nevertheless, diagnosis of EGPA may be difficult or delayed not only because of the rarity of the disease, but also because other diseases can present with similar manifestations.

AREAS COVERED

We review a series of key areas in EGPA, namely, laboratory and clinical indicators of disease, diagnosis, role of biomarkers, induction and maintenance therapy, and use of traditional and novel drugs. This narrative review was based on a thorough search of PubMed.

EXPERT OPINION

Clinicians should be aware of the limitations of available tools for diagnosing EGPA, and more efforts should be made to identify clinical and laboratory red flags, with the purpose of achieving an early diagnosis before irreversible damage occurs. New effective therapies are available, although future research should target an approach that spares glucocorticoids, reduces the risk of flares and organ damage, and maintains long-term remission with minimum adverse effects.

Treatment with oclacitinib, a Janus kinase inhibitor, down-regulates and up-regulates CD25 and Foxp3 expression, respectively, in peripheral blood T cells of dogs with atopic dermatitis

BACKGROUND

Oclacitinib (OCL), a Janus kinase inhibitor, is a novel immunomodulatory/immunosuppressive agent which is an approved as the first-line treatment for atopic dermatitis (AD) in dogs. The aim of the study was to investigate the effects of OCL on CD4+ and CD8+ T cells and their selected subsets under clinical conditions, i.e. in dogs suffering from AD, in terms of both safety and immune mechanisms underlying its therapeutic actions. Eight dogs were treated for 28 days with OCL at the recommended dose. Blood samples were taken at day 0, 7, 14 and 28.

RESULTS

The study showed that the mean percentage and absolute count of CD4+ and CD8+ T cells on the 14th and 28th day of the treatment with OCL did not differ from the corresponding baseline values, i.e. those before the treatment. On the 7th day of the treatment, the mean absolute count of CD4+ T cells and the mean percentage and absolute count of CD8+ T cells were significantly increased. The research found that on the 14th day of the treatment, the mean percentage and absolute count of CD25+CD4+ and CD25+CD8+ T cells were significantly decreased; the reduction in the percentage of CD25+CD4+ T cells persisted on 28th day of the treatment. A two-week treatment with OCL resulted in an increase in the mean percentage of Foxp3+CD4+ T cells, and this effect was sustained at the last time point. The treatment with OCL decreased the eosinophil level but does not affect the absolute counts of basophils, monocytes and neutrophils.

CONCLUSIONS

The findings of the study strongly suggest that: (a) in terms of the impact of OCL on the number of PB CD4+ and CD8+ T cells, monthly treatment with the drug should be considered as a relatively safe; (b) the eosinophil-reducing effect and the down-regulation of the AD up-regulated CD25 expression on CD4+ Teff cells may constitute significant elements of the mechanism of action underlying the therapeutic effects of the drug in the treatment of canine AD; (c) the generation of inducible Foxp3-expressing CD4+ regulatory T cells - resulting in the shift of the CD4+ Treg cell (i.e. Foxp3+CD4+)/activated Teff (i.e. CD25+CD4+) cell balance toward an increased proportion of Treg cells - may be considered as additional mechanism involved in producing the immunomodulatory/immunosuppressive properties of OCL.

Type 2 responses determine skin rash during recombinant interleukin-2 therapy

The skin is the organ most often affected by adverse drug reactions. Although these cutaneous adverse drug reactions (CADRs) often are mild, they represent a major burden for patients. One of the drugs inducing CADRs is aldesleukin, a recombinant interleukin-2 (recIL-2) originally approved to treat malignant melanoma and metastatic renal cell carcinoma which frequently led to skin rashes when applied in high doses for anti-cancer therapy. Skin rashes and other side effects, together with poor efficacy led to a drawback of the therapeutic, but modified recIL-2 molecules are on the rise to treat both cancer and inflammatory diseases such as autoimmunity. Still, pathophysiological mechanisms of recIL-2-induced skin rashes are not understood. In the study reported here, a hypothetical literature-based immune-related adverse outcome pathway (irAOP) was developed to identify possible key cells and molecules in recIL-2-induced skin rash. Using this approach, a hypothesis was formed that the induced immune response predominantly is Type 2-driven by T-helper and innate lymphoid cells, leading to the occurrence of cutaneous side effects during recIL-2 therapy. This paper further discusses mechanisms beyond the proposed irAOP which might add to the pathology but currently are less-studied. Together, this hypothetic irAOP forms a basis to clarify possible cellular and molecular interactions leading to recIL-2-induced skin rash. This might be used to adapt existing or develop new test systems to help predict and prevent cutaneous side effects in future IL-2-based or similar therapies.

The Role of Eosinophils in Liver Disease

Previously, eosinophils were primarily regarded as effector toxic cells involved in allergic diseases and parasitic infections. Nevertheless, new research has shown that eosinophils are diverse and essential for immune regulation and tissue homeostasis. Their functional plasticity has been observed in patients with inflammatory diseases, cancer, infections, and other disorders. Although eosinophils are infrequently observed within the liver during periods of homeostasis, they are recruited to the liver in various liver diseases, including liver parasitosis, acute liver injury, autoimmune liver disease, and hepatocellular carcinoma. Furthermore, eosinophils have demonstrated the capacity to promote liver regeneration. This article explores the multifaceted roles of eosinophils in liver diseases, aiming to provide insights that could lead to more effective clinical therapies for these conditions.

A Review on Asthma and Allergy: Current Understanding on Molecular Perspectives

Asthma, a complex disease characterized by persistent airway inflammation, remains an urgent global health concern. We explored the critical role of allergic biomarkers and dysregulated immune system in asthma through an extensive literature review in databases such as Web of Science, PubMed, EMBASE, Scopus, and Google Scholar. This review summarizes the growing data on the pivotal role of allergic biomarkers and dysregulated immune system in the development and evolution of asthma. Recent studies have uncovered several biomarkers that elucidate intrinsic allergic mechanisms in individuals with asthma. This article highlights these biomarkers' potential in predicting asthma onset, assessing its intensity, guiding therapeutic interventions, and tracking disease progression. We also explore the innovative therapeutic prospects arising from the convergence of allergy and dysregulated immune system in asthma and emphasize the potential for precision medicine approaches. Understanding allergic biomarkers intertwined with a dysregulated immune system heralds a new era in asthma treatment and points to improved and individualized treatment modalities.

Quantification of eosinophils in the lower gastrointestinal tract of adults: a review of surgical specimens with normal histology from the Free State province, South Africa

AIM

Eosinophils are normal residents of the gastrointestinal tract (GIT). They are noted in small numbers with significant variation between anatomic locations. An idiopathic increase of eosinophils is known as eosinophilic gastrointestinal disease (EGID). EGIDs are a heterologous group of disorders that produce a range of enteric and colonic syndromes. Their incidence has been increasing worldwide. Our study aimed to quantify eosinophils in each segment of the GIT in surgical specimens with normal histology to facilitate the histological diagnosis of EGID. Similarly, we aimed to describe the effect of race and gender on gastrointestinal eosinophil numbers.

METHODS

A retrospective, quantitative comparative study was performed. We assessed 360 surgical specimens with normal histology from the lower gastrointestinal tract of African and Caucasian adults from the Free State Province, South Africa. The number of eosinophils per mm² was counted.

RESULTS

Overall, comparable eosinophil values were noted for both males and females, and African and Caucasian South Africans. However, Caucasians recorded a higher concentration of eosinophils in the appendix and the left colon. Eosinophils were most numerous in the lamina propria, with only small numbers present in the epithelium. Our results show that the South African population has similar eosinophil distribution trends to international studies. However, South Africans had far fewer eosinophils than Japanese and North American adults in each segment.

CONCLUSIONS

Specific eosinophil reference ranges were formulated to quantify reference ranges of eosinophils in the lower GIT, allowing for the accurate diagnosis of EGIDs in our population in future.

Probable idiopathic hypereosinophilic syndrome: A case report of severe multi-organ eosinophilic involvement in a young male presenting with heart failure

Hypereosinophilic syndrome (HES) is a disorder characterized by elevated levels of eosinophils, which may be associated with multi-organ involvement depending on severity. The recent diagnostic criteria for idiopathic HES require an elevated absolute eosinophil count (AEC) above 1500 cells/mcL with evidence of tissue damage. We present a case of a 37-year-old male firefighter with a purported history of eosinophilic bronchitis who was referred to the hospital with syncopal episodes and a persistent productive cough. The patient showed an AEC of 4500 cells/mcL on admission associated with high inflammatory markers. Cardiac imaging demonstrated acute myocarditis with heart failure and a reduced ejection fraction. Chest imaging was initially suggestive of community-acquired pneumonia. Workup was negative for a malignant etiology; infectious causes similarly were excluded. After a multidisciplinary evaluation, a diagnosis of idiopathic HES was made and steroids were instituted with rapid resolution of symptoms. Our case illustrates the importance of considering hypereosinophilia as a precipitating factor for acute heart failure in an otherwise healthy adult. An expeditious diagnosis can lead to early initiation of steroids to avoid progression toward multi-organ failure.

Ally, adversary, or arbitrator? The context-dependent role of eosinophils in vaccination for respiratory viruses and subsequent breakthrough infections

Eosinophils are a critical type of immune cell and central players in type 2 immunity. Existing literature suggests that eosinophils also can play a role in host antiviral responses, typically type 1 immune events, against multiple respiratory viruses, both directly through release of antiviral mediators and indirectly through activation of other effector cell types. One way to prime host immune responses toward effective antiviral responses is through vaccination, where typically a type 1-skewed immunity is desirable in the context of intracellular pathogens like respiratory viruses. In the realm of breakthrough respiratory viral infection in vaccinated hosts, an event in which virus can still establish productive infection despite preexisting immunity, eosinophils are most prominently known for their link to vaccine-associated enhanced respiratory disease upon natural respiratory syncytial virus infection. This was observed in a pediatric cohort during the 1960s following vaccination with formalin-inactivated respiratory syncytial virus. More recent research has unveiled additional roles of the eosinophil in respiratory viral infection and breakthrough infection. The specific contribution of eosinophils to the quality of vaccine responses, vaccine efficacy, and antiviral responses to infection in vaccinated hosts remains largely unexplored, especially regarding their potential roles in protection. On the basis of current findings, we will speculate upon the suggested function of eosinophils and consider the many potential ways by which eosinophils may exert protective and pathological effects in breakthrough infections. We will also discuss how to balance vaccine efficacy with eosinophil-related risks, as well as the use of eosinophils and their products as potential biomarkers of vaccine efficacy or adverse events.

Effect of benralizumab on histopathology and inflammatory signatures in a clinical cohort of eosinophilic esophagitis

A preliminary report from the recent phase 3 trial of benralizumab, a monoclonal antibody that binds to interleukin-5 receptor alpha (IL5Rα), in patients with EoE revealed that medication use led to tissue eosinophil eradication but did not meet the clinical endpoint of symptom resolution. Here, we characterized the clinical, endoscopic, histologic, and transcriptional changes in patients with active EoE following benralizumab treatment. We retrospectively examined patients with EoE treated with benralizumab at the University of Utah (n = 11) and reviewed reported clinical symptoms, circulating and tissue eosinophilia, and endoscopic and histologic scores. Gene expression profiles from available esophageal tissue from benralizumab-treated patients were compared to those from patients with remission EoE (n = 5), active EoE (n = 10), and controls (n = 22). Benralizumab treatment resulted in partial symptom improvement and significant reduction in tissue eosinophilia, and endoscopic and histologic disease scoring (P < 0.01). Histologic score reductions were driven by eosinophil feature scores, while scores for epithelial features (basal cell hyperplasia and dilated intercellular spaces) were similar to those in active EoE. The gene signatures in benralizumab-treated patients mimicked those of active EoE (e.g. upregulation of POSTN, CDH26, CCL26, and downregulation of DSG1). RNA profiles and pathways support histologic findings of impaired epithelial function that persists despite benralizumab treatment. In conclusion, despite eosinophil eradication, patients treated with benralizumab had persistent epithelial injury at the histologic and transcriptional level. In this cohort, benralizumab therapy failed to eradicate inflammation and epithelial dysfunction showing that interleukin-5 receptor alpha blockade monotherapy is insufficient to control EoE.

Peripheral inflammation as a potential mechanism and preventive strategy for perioperative neurocognitive disorder under general anesthesia and surgery

General anesthesia, as a commonly used medical intervention, has been widely applied during surgical procedures to ensure rapid loss of consciousness and pain relief for patients. However, recent research suggests that general anesthesia may be associated with the occurrence of perioperative neurocognitive disorder (PND). PND is characterized by a decline in cognitive function after surgery, including impairments in attention, memory, learning, and executive functions. With the increasing trend of population aging, the burden of PND on patients and society's health and economy is becoming more evident. Currently, the clinical consensus tends to believe that peripheral inflammation is involved in the pathogenesis of PND, providing strong support for further investigating the mechanisms and prevention of PND.

Evaluation of Anticonvulsant-Induced Leukocytosis: A Review of Evidence for Carbamazepine, Lamotrigine, and Phenobarbital

Objective: The objective was to determine the incidence of leukocytosis associated with carbamazepine, lamotrigine, and phenobarbital. Data sources: A comprehensive literature review was conducted with the assistance of a medical reference librarian on PubMed, MEDLINE, Embase, and Google Scholar through June 2023 using the following search terminology: "leukocytosis/chemically induced"[MeSH Terms] AND ("Anticonvulsants"[MeSH Terms] OR ("Anticonvulsants"[Pharmacological Action] OR "Anticonvulsants"[MeSH Terms] OR "Anticonvulsants"[All Fields] OR "anticonvulsant"[All Fields] OR "anticonvulsion"[All Fields] OR "anticonvulsive"[All Fields] OR "anticonvulsives"[All Fields]) OR ("Anticonvulsants"[Pharmacological Action] OR "Anticonvulsants"[MeSH Terms] OR "Anticonvulsants"[All Fields] OR "antiepileptic"[All Fields] OR "antiepileptics"[All Fields])). Study selection and data extraction: Thirteen reports were included from 64 potential results of our literature review following the application of inclusion and exclusion criteria: 7 of the reports involved carbamazepine, 4 of the reports involved lamotrigine, and 2 of the reports involved phenobarbital. Data synthesis: Drug-induced leukocytosis is commonly a diagnosis of exclusion and is a phenomenon that has numerous ramifications to patients and clinicians at the bedside, including mandating a full infectious evaluation, the identification of confounding variables, and the eventual discontinuation of the offending agent. Despite several medications and medication classes possessing this adverse drug effect, an evaluation of the specific clinical presentation and management strategies for drug-induced leukocytosis associated with anticonvulsant medications has not been elucidated in the literature. Conclusions: Clinicians should be judicious when evaluating leukocytosis in patients on potentially precipitating medications, including carbamazepine, lamotrigine, and phenobarbital.

Skin, gut, and lung barrier: Physiological interface and target of intervention for preventing and treating allergic diseases

The epithelial barriers of the skin, gut, and respiratory tract are critical interfaces between the environment and the host, and they orchestrate both homeostatic and pathogenic immune responses. The mechanisms underlying epithelial barrier dysfunction in allergic and inflammatory conditions, such as atopic dermatitis, food allergy, eosinophilic oesophagitis, allergic rhinitis, chronic rhinosinusitis, and asthma, are complex and influenced by the exposome, microbiome, individual genetics, and epigenetics. Here, we review the role of the epithelial barriers of the skin, digestive tract, and airways in maintaining homeostasis, how they influence the occurrence and progression of allergic and inflammatory conditions, how current treatments target the epithelium to improve symptoms of these disorders, and what the unmet needs are in the identification and treatment of epithelial disorders.

Two-sample Mendelian randomization analysis of the causal relationship between blood eosinophils and allergic rhinitis

OBJECTIVES

Previous studies have revealed a correlation between eosinophils and allergic rhinitis, but the causal relationship has not been fully confirmed. This study aims to evaluate the causal link between blood eosinophils and allergic rhinitis using the Mendelian randomization (MR) method.

METHODS

Summary data from the Genome-Wide Association Study Catalog (GWAS) for eosinophil count (exposure variable) and allergic rhinitis (outcome variable) were collected. GWAS data for the exposure variable were obtained from the IEU Open GWAS Project developed by the Integrative Epidemiology Unit at the University of Bristol, while data for the outcome variable were sourced from the FinnGen Biobank (Finland) database. The causal relationship between eosinophils and allergic rhinitis was analyzed using the two-sample MR method with inverse variance weighted (IVW) analysis. Sensitivity analyses were conducted using the weighted median method, MR-Egger regression, leave-one-out analysis, and funnel plots.

RESULTS

An increase in blood eosinophil count showed a potential causal relationship with an increased risk of allergic rhinitis (OR=1.187, 95% CI 1.051 to 1.341, P=0.006). This finding was consistent across the weighted median method and MR-Egger regression. Leave-one-out analysis indicated that no single nucleotide polymorphism significantly influenced the causal inference.

CONCLUSIONS

There is a causal association between increased eosinophil count and a higher risk or worsening of allergic rhinitis.

Severe hypereosinophilia in a patient treated with dupilumab and shift to mepolizumab: the importance of multidisciplinary management. A case report and literature review

Type 2 inflammation is a heterogeneous condition due to the complex activation of different immunological pathways. Rapid progress in research to evaluate the efficacy of biologics for chronic rhinosinusitis with nasal polyps and asthma has led to the availability of effective therapeutic options. These drugs are safe, but temporary iatrogenic hypereosinophilia may sometimes be associated with clinical symptoms or organ damage. Here, we describe a case of severe hypereosinophilia in a patient with chronic rhinosinusitis with nasal polyps and asthma treated with dupilumab and a subsequent therapeutic shift to mepolizumab that led to maintenance of symptom control and concomitant normalization of blood eosinophil count.

Eosinophils and Cognitive Impairment in Schizophrenia: A New Perspective

Schizophrenia is a complex psychiatric disorder characterized by a wide array of cognitive impairments. While research has predominantly focused on the neurological aspects of schizophrenia, emerging evidence suggests that the immune system, specifically eosinophils, may play a significant role in the cognitive deficits associated with the disorder. This review presents a novel perspective on the interplay between eosinophils and cognitive impairment in schizophrenia. Eosinophils, traditionally associated with allergic responses and inflammation, have garnered limited attention within the realm of neuropsychiatry. Recent studies have hinted at a potential link between eosinophil activation and the pathogenesis of schizophrenia. In this comprehensive review, we delve into the world of eosinophils, elucidating their nature, functions, and interactions with the immune system. We examine the cognitive deficits observed in individuals with schizophrenia and discuss existing theories on the etiology of these impairments, focusing on immune system involvement. The paper also highlights the evolving body of research that supports the idea of eosinophilic influence on schizophrenia-related cognitive deficits. Furthermore, we explore potential mechanisms through which eosinophils may exert their effects on cognitive function in schizophrenia, including interactions with other immune cells and inflammatory pathways. By discussing the clinical implications and potential therapeutic avenues stemming from this newfound perspective, we underscore the practical significance of this emerging field of research. While this paper acknowledges the limitations and challenges inherent in studying eosinophils within the context of schizophrenia, it serves as a posit for novel thought in this vexing disease space as well as a call to action for future research endeavors. By providing a comprehensive survey of the existing literature and posing unanswered questions, we aim to inspire a reimagining of the relationship between eosinophils and cognitive impairment in schizophrenia, ultimately advancing our understanding and treatment of this debilitating disorder.

Multi-Disciplinary Expert Perspective on the Management of Type 2 Inflammation-Driven Severe CRSwNP: A Brief Overview of Pathophysiology and Recent Clinical Insights

Severe chronic rhinosinusitis with nasal polyposis (CRSwNP) is a disabling airway disease that significantly impacts patients' lives through the severity of symptoms, the need for long-term medical treatment and the high risk of recurrence post-surgery. Biological agents targeting type 2 immune responses underlying the pathogenesis of CRSwNP have shown effectiveness in reducing polyp size and eosinophilic infiltrate, and in decreasing the need for additional sinus surgeries. However, despite recent progress in understanding and treating the disease, type 2 inflammation-driven severe CRSwNP continues to pose challenges to clinical management due to several factors such as persistent inflammation, polyp recurrence, heterogeneity of disease, and comorbidities. This article presents the findings of a scientific discussion involving a panel of ear, nose and throat (ENT) specialists and pulmonologists across Sweden and Finland. The discussion aimed to explore current management practices for type 2 inflammation-driven severe CRSwNP in the Nordic region. The main topics examined encompassed screening and referral, measurements of disease control, treatment goals, and future perspectives. The experts emphasized the importance of a collaborative approach in the management of this challenging patient population. The discussion also revealed a need to broaden treatment options for patients with type 2 inflammation-driven CRSwNP and comorbid conditions with shared type 2 pathophysiology. In light of the supporting evidence, a shift in the disease model from the presence of polyps to that of type 2 inflammation may be warranted. Overall, this discussion provides valuable insights for the scientific community and can potentially guide the future management of CRSwNP.

The Role of Extracellular Traps in HIV Infection

Human immunodeficiency virus (HIV) infection is still an important public health problem, which justifies the research of new therapies to combat it. Recent studies show that Extracellular Traps (ETs) are cellular mechanisms useful in the capture and destruction of some viruses, such as the HIV. Here, we show that neutrophils from peripheral blood, genital tissues, and placenta are activated when exposed to human immunodeficiency virus type 1 (HIV-1) and release Neutrophil Extracellular Traps (NETs). The NETs can capture, neutralize, and inactivate the virus and, also, protect other target cells from HIV infection, as long as the DNA and other constituents of the NETs remain intact. Further, the review indicates that the immunoprotective role of NETs in the context of HIV-1 infection is a promising finding for the development of new antiviral therapies. It is necessary, however, the development of studies that evaluate the tissue injury that NETs can cause and the biological relationships with other cells to improve them as therapeutic targets.

Automated, Point-of-Care mobile flow cytometry: Bringing the laboratory to the sample

Background

Innate effector cells are very responsive to infectious and inflammatory cues found in damaged and inflamed tissues. Their activation is a potential target to assess the state of the immune system. Unfortunately, these cells are very susceptible for ex-vivo activation, hampering accurate interpretation of flow cytometry data. Whether a brief window exists before ex-vivo activation starts to occur is currently unknown.

Aims

1) This study extensively investigated ex-vivo activation of innate effector cells over time. 2) We tested the feasibility of applying a mobile, automated, flow cytometry laboratory for out-of-hospital Point-of-Care analyses to minimize ex-vivo activation bias.

Methods

1) Ex-vivo neutrophil, eosinophil and monocyte activation in a blood collection tube over time and the reactivity to a formyl-peptide was investigated in a healthy cohort. 2) To facilitate fast, out-of-hospital analysis, application of the mobile flow cytometry was tested by placing an automated flow cytometer into a van. The stability of the setup was assessed by repetitively measuring laser alignment and fluorescence verification beads.

Findings

1) Immediately after venipuncture activation marker expression on neutrophils, eosinophils and monocyte subsets started to change in a time-dependent manner. 2) The mobile flow cytometry laboratory travelled over 3000 km, performing measurements at 19 locations with a median single-person-set-up time of 14 min. The laser alignment and fluorescence were stable during all experiments.

Conclusions

Accurate flow data of innate immune cells are only obtained when ex-vivo activation is kept to minimum. The use of a mobile, fast, automated, flow cytometry laboratory for out-of-hospital Point-of-Care analyses provides new investigational and diagnostic possibilities outside major hospital flow cytometry laboratories.

Membrane damage by MBP-1 is mediated by pore formation and amplified by mtDNA

Eosinophils play a crucial role in host defense while also contributing to immunopathology through the release of inflammatory mediators. Characterized by distinctive cytoplasmic granules, eosinophils securely store and rapidly release various proteins exhibiting high toxicity upon extracellular release. Among these, major basic protein 1 (MBP-1) emerges as an important mediator in eosinophil function against pathogens and in eosinophil-associated diseases. While MBP-1 targets both microorganisms and host cells, its precise mechanism remains elusive. We demonstrate that formation of small pores by MBP-1 in lipid bilayers induces membrane permeabilization and disrupts potassium balance. Additionally, we reveal that mitochondrial DNA (mtDNA) present in eosinophil extracellular traps (EETs) amplifies MBP-1 toxic effects, underscoring the pivotal role of mtDNA in EETs. Furthermore, we present evidence indicating that absence of CpG methylation in mtDNA contributes to the regulation of MBP-1-mediated toxicity. Taken together, our data suggest that the mtDNA scaffold within extracellular traps promotes MBP-1 toxicity.

Eosinophilic giant cell arteritis: A different subset of disease?

OBJECTIVES

To describe the clinical findings, response to therapy and course of patients with transmural eosinophilic infiltration at temporal artery biopsy (TAB).

METHODS

The study consisted of a retrospective cohort of 254 consecutive GCA patients with evidence of transmural inflammation at TAB seen at the Santa Maria Nuova Hospital over a 28-year period. The findings of the 22 patients with eosinophilic infiltration (≥ 20 eosinophils/hpf) at TAB were compared with those of 232 patients without. Among these 232 patients, we sampled 42 GCA patients matched for age, sex and follow-up duration to the 22 with eosinophilic infiltration, to compare allergic manifestations.

RESULTS

GCA patients with eosinophilic infiltration compared to those without presented more frequently cranial symptoms (p = 0.052), headaches (p = 0.005), abnormalities of TAs at physical examination (p = 0.045), jaw claudication (p = 0.024), and systemic manifestations (p = 0.016) and had higher CRP levels at diagnosis (p = 0.001). Regarding histological lesions, a severe transmural inflammation, laminar necrosis and intraluminal acute thrombosis were more frequently observed in patients with eosinophilic infiltration (p = 0.066, p < 0.001, and p = 0.010, respectively). Long-term remission and flares were similar in the two groups. When 21 GCA patients with eosinophilic infiltration were compared to 42 without, blood eosinophilic counts at diagnosis were normal and no patients had evidence or developed allergic manifestations and/or clinical findings of systemic necrotizing vasculitis.

CONCLUSION

Patients with transmural eosinophilic infiltration represent a subset of GCA with cranial disease and more severe inflammation.

Peripheral Blood Eosinophilia in Patients with Diabetic Foot Infection Receiving Long-Term Antibiotic Therapy

Background: The eosinophil level in peripheral blood increases in response to various conditions, the most common being medication use. Since the outcome of increased levels of eosinophils can range from a benign finding to extensive damage to host organs and systemic consequences, this finding raises concern among clinicians. We aimed to assess the prevalence of prolonged antibiotic-therapy-induced eosinophilia and possible outcomes. Methods: We conducted a retrospective cohort study of diabetic patients admitted to the orthopedic department from December 2016 through December 2020 due to a moderate to severe diabetic foot infection and who received at least 14 days of antibiotic therapy. Patients were identified retrospectively through the orthopedic department registry, and their files were reviewed, extracting demographics, laboratory test results, antibiotic treatment, and outcomes. Results: The cohort included 347 patients; a total of 114 (32.8%) developed eosinophilia during the follow-up period. Patients who developed eosinophilia had a significantly longer duration of antibiotic treatment (p < 0.001) and a significantly longer hospitalization (p = 0.001). For multivariable analysis, the independent risk factors predicting drug-induced eosinophilia included older age, higher eosinophil count on admission (per quantile) and higher platelet count on admission (per quantile) (p = 0.012, p < 0.001, p = 0.009, respectively). There was no evidence of complications in patients who developed eosinophilia compared to patients who did not. No significant association with a specific type of antibiotic was found. Conclusions: We found a higher incidence of drug-induced eosinophilia than expected or previously described. The factors associated with eosinophilia included age and higher baseline eosinophil and platelet levels but not antibiotic type.

Combining WGCNA and machine learning to identify mechanisms and biomarkers of ischemic heart failure development after acute myocardial infarction

Background

Ischemic heart failure (IHF) is a serious complication after acute myocardial infarction (AMI). Understanding the mechanism of IHF after AMI will help us conduct early diagnosis and treatment.

Methods

We obtained the AMI dataset GSE66360 and the IHF dataset GSE57338 from the GEO database, and screened overlapping genes common to both diseases through WGCNA analysis. Subsequently, we performed GO and KEGG enrichment analysis on overlapping genes to elucidate the common mechanism of AMI and IHF. Machine learning algorithms are also used to identify key biomarkers. Finally, we performed immune cell infiltration analysis on the dataset to further evaluate immune cell changes in AMI and IHF.

Results

We obtained 74 overlapping genes of AMI and IHF through WGCNA analysis, and the enrichment analysis results mainly focused on immune and inflammation-related mechanisms. Through the three machine learning algorithms of LASSO, RF and SVM-RFE, we finally obtained the four Hub genes of IL1B, TIMP2, IFIT3, and P2RY2, and verified them in the IHF dataset GSE116250, and the diagnostic model AUC = 0.907. The results of immune infiltration analysis showed that 8 types of immune cells were significantly different in AMI samples, and 6 types of immune cells were significantly different in IHF samples.

Conclusion

We explored the mechanism of IHF after AMI by WGCNA, enrichment analysis, and immune infiltration analysis. Four potential diagnostic candidate genes and therapeutic targets were identified by machine learning algorithms. This provides a new idea for the pathogenesis, diagnosis, and treatment of IHF after AMI.

Presumptive pulmonary toxocariasis in a patient affected by acute myeloid leukemia and Hodgkin lymphoma: case report and review of the literature in immunocompromised hosts

Toxocariasis is a zoonosis transmitted by the nematode Toxocara spp. Immunocompromised hosts are more susceptible than general population to bacterial, viral, fungal and parasitic infections. In this population toxocariasis may present as exacerbation or reactivation and could have severe or atypical manifestations being a diagnostic challenge for healthcare providers. We report a case of a presumptive pulmonary toxocariasis during chemotherapy in a patient affected by acute myeloid leukaemia (AML) and Hodgkin lymphoma and we summarize current evidence of pulmonary involvement in immunocompromised population with Toxocara spp infection in a narrative review. The aim of this work is also to revise the current literature on pulmonary involvement during Toxocara spp infection in immunocompromised hosts to improve knowledge on clinical presentation, treatment and outcome. A 66 years old man who had undergone to a cytarabine and idarubicin chemotherapy induction scheme for AML, complained of febrile neutropenia and dry cought. At the chest computed tomography (CT) there were multiple nodular pulmonary lesions with subpleural consolidations. The lung biopsy revealed inflammatory infiltration with diffuse small granulomas with minor eosinophil component. The laboratory analysis showed high immunoglobulin E (IgE) count with normal peripherical eosinophils, among the extended parasitological analysis, Toxocara immunoblot assay resulted positive. In the most accepted hypothesis of a polmunary toxocariasis infection, the patient was treated with a combination of albendazole plus corticosteroids for four weeks, with a positive outcome. Infection complications during chemotherapy are not uncommon, however, this is the first reported case of pulmonary toxocariasis during cytarabine and idarubicin treatment in AML. The revised literature shows male gender and younger age as possible risk factors, nevertheless the majority of cases of seropositivity for Toxocara was reported in solid organ malignancies. In this case, the suspect was mainly based on laboratory total elevated IgE, confirmed by serological, anatomo-pathological and radiological findings. Hypereosinophilia is often not present in chronic infection. In conclusion, pulmonary toxocariasis should be ruled out in patients with pulmonary involvement and high IgE titre, with or without peripheral eosinophilia, especially in those with known immunocompromised status.

Eosinophils of patients with localized and diffuse cutaneous leishmaniasis: Differential response to Leishmania mexicana, with insights into mechanisms of damage inflicted upon the parasites by eosinophils

Eosinophils are mainly associated with parasitic infections and allergic manifestations. They produce many biologically active substances that contribute to the destruction of pathogens through the degranulation of microbicidal components and inflammatory tissue effects. In leishmaniasis, eosinophils have been found within inflammatory infiltrate with protective immunity against the parasite. We analyzed the responses of eosinophils from patients with localized (LCL) and diffuse (DCL) cutaneous leishmaniasis, as well as from healthy subjects, when exposed to Leishmania mexicana. All DCL patients exhibited blood eosinophilia, along with elevated eosinophil counts in non-ulcerated nodules. In contrast, only LCL patients with prolonged disease progression showed eosinophils in their blood and cutaneous ulcers. Eosinophils from DCL patients secreted significantly higher levels of IL-6, IL-8, and IL-13, compared to eosinophils from LCL patients. Additionally, DCL patients displayed higher serum levels of anti-Leishmania IgG antibodies. We also demonstrated that eosinophils from both LCL and DCL patients responded to L. mexicana promastigotes with a robust oxidative burst, which was equally intense in both patient groups and significantly higher than in healthy subjects. Coincubation of eosinophils (from donors with eosinophilia) with L. mexicana promastigotes in vitro revealed various mechanisms of parasite damage associated with different patterns of granule exocytosis: 1) localized degranulation on the parasite surface, 2) the release of cytoplasmic membrane-bound "degranulation sacs" containing granules, 3) release of eosinophil extracellular traps containing DNA and granules with major basic protein. In conclusion, eosinophils damage L. mexicana parasites through the release of granules via diverse mechanisms. However, despite DCL patients having abundant eosinophils in their blood and tissues, their apparent inability to provide protection may be linked to the release of cytokines and chemokines that promote a Th2 immune response and disease progression in these patients.

Staphylococcus aureus proteases trigger eosinophil-mediated skin inflammation

Staphylococcus aureus skin colonization and eosinophil infiltration are associated with many inflammatory skin disorders, including atopic dermatitis, bullous pemphigoid, Netherton's syndrome, and prurigo nodularis. However, whether there is a relationship between S. aureus and eosinophils and how this interaction influences skin inflammation is largely undefined. We show in a preclinical mouse model that S. aureus epicutaneous exposure induced eosinophil-recruiting chemokines and eosinophil infiltration into the skin. Remarkably, we found that eosinophils had a comparable contribution to the skin inflammation as T cells, in a manner dependent on eosinophil-derived IL-17A and IL-17F production. Importantly, IL-36R signaling induced CCL7-mediated eosinophil recruitment to the inflamed skin. Last, S. aureus proteases induced IL-36α expression in keratinocytes, which promoted infiltration of IL-17-producing eosinophils. Collectively, we uncovered a mechanism for S. aureus proteases to trigger eosinophil-mediated skin inflammation, which has implications in the pathogenesis of inflammatory skin diseases.

Cebp1 and Cebpβ transcriptional axis controls eosinophilopoiesis in zebrafish

Eosinophils are a group of granulocytes well known for their capacity to protect the host from parasites and regulate immune function. Diverse biological roles for eosinophils have been increasingly identified, but the developmental pattern and regulation of the eosinophil lineage remain largely unknown. Herein, we utilize the zebrafish model to analyze eosinophilic cell differentiation, distribution, and regulation. By identifying eslec as an eosinophil lineage-specific marker, we establish a Tg(eslec:eGFP) reporter line, which specifically labeled cells of the eosinophil lineage from early life through adulthood. Spatial-temporal analysis of eslec+ cells demonstrates their organ distribution from larval stage to adulthood. By single-cell RNA-Seq analysis, we decipher the eosinophil lineage cells from lineage-committed progenitors to mature eosinophils. Through further genetic analysis, we demonstrate the role of Cebp1 in balancing neutrophil and eosinophil lineages, and a Cebp1-Cebpβ transcriptional axis that regulates the commitment and differentiation of the eosinophil lineage. Cross-species functional comparisons reveals that zebrafish Cebp1 is the functional orthologue of human C/EBPεP27 in suppressing eosinophilopoiesis. Our study characterizes eosinophil development in multiple dimensions including spatial-temporal patterns, expression profiles, and genetic regulators, providing for a better understanding of eosinophilopoiesis.

Ethnic variation in asthma phenotypic presentation and outcomes: a cross-sectional analysis of the UK Biobank

Ethnic disparities exist within asthma; however, country of birth is rarely investigated. We described demographic and clinical characteristics by ethnicity and country of birth within the UK Biobank. Lung function and asthma hospitalisations were similar for white, black and North-East Asian participants, however, South-East (SE) Asians more commonly had an FEV1 below the lower limits of normal (LLN; 53.8% vs 32.3%, p<0.001), blood eosinophilia (38.6% vs 23.8%, p<0.001) and asthma hospitalisation (12.5% vs 8.3%, p<0.001) than white participants. First-generation SE Asian immigrants had poorer lung function (57.7% vs 27.7% FEV1 below LLN, p<0.001) than UK/Ireland born participants. These data demonstrate inter-ethnic and intra-ethnic disparities.

An assessment of the immune status of some stone quarry workers in Ondo state, Nigeria

Stone quarry activities in Nigeria are mostly unregulated such that the workers in these quarries are continuously exposed to the inhalation of silica dust. It has been observed that silica dust particles negatively impact the health of stone quarry workers which usually manifest as respiratory difficulties, asthma-like illnesses and other adventitious events of the lungs. The study was designed to evaluate the probable immunological impact of silica dust inhalation from stone crushing by workers. Blood samples were collected from consenting workers and analyzed for total white blood cells and their subsets. Absolute CD4 cells numbers were also determined. The results indicated that neutrophils and eosinophils numbers increased significantly (P < .05) and CD4 counts declined significantly (P < .001). Alteration in these proportions is a pointer to the injurious impact of silica dust on the immune system of these workers. The findings in this study should spur actions in the education of these workers on the need for the use of proper personal protection equipment and the establishment of a scheme to periodically carry out a health assessment check to identity those at most risk of developing chronic illnesses.

Association Between Elevated Blood Eosinophils and Chronic Kidney Disease Progression: Analyses of a Large United States Electronic Health Records Database

Background

Blood eosinophils can increase in response to infection, inflammation, and hypersensitivity reactions, yet their involvement in the progression of chronic kidney disease (CKD) is poorly understood. This study explores the relationship between blood eosinophils and CKD progression among patients in a real-world setting.

Methods

This retrospective study analyzed data obtained from the Optum® de-identified electronic health records dataset in the United States. Patients diagnosed with CKD stage 3 or 4 (International Classification of Diseases diagnosis code or estimated glomerular filtration rate [eGFR] <60 mL/min) between January 2011 and March 2018 were included and followed until progression to the next CKD stage, death, or dropout. The primary objective of this study was to assess the relationship between blood eosinophil counts (bEOS) and CKD progression, adjusting for clinical and demographic features as well as known risk factors for CKD stages 3-4. The primary outcomes were CKD progression and all-cause mortality.

Results

We found that high eosinophilic levels (bEOS ≥300 cells/µL) were associated with CKD progression from stage 3 to stages 4 or 5 (hazard ratio [HR] ranging from 1.30 to 1.50) and from stages 4 to 5 (HR ranging from 1.28 to 1.50). Among patients with CKD progression, those with blood eosinophils ≥300 cells/µL appeared to have a relatively lower eGFR, higher all-cause mortality, and reduced time to CKD progression and death than those with <300 cells/µL. Factors including sex, race, hypertension, anemia, and treatments for cardiovascular and hematopoietic drugs were associated with CKD progression.

Conclusion

Elevated eosinophils may increase the risk for CKD progression. Larger studies are needed to assess whether the risk of mortality is increased among patients with elevated eosinophils.

Association between low eosinophil count and acute bacterial infection, a prospective study in hospitalized older adults

BACKGROUND

The incidence of sepsis increases significantly with age, including a high incidence of bacterial infection in the old adults. Eosinopenia and the CIBLE score have been proposed in critically ill adults and in internal medicine wards. This study aimed to assess whether a low eosinophil count was associated with acute bacterial infection among hospitalized older adults, and to find the most efficient eosinophil count cut-off to differentiate acute bacterial infection from other inflammatory states.

METHODS

This was a prospective study from July 2020 to July 2022 in geriatric wards of the University Paul Brousse Hospital (Villejuif, France) including patients aged of 75 y/o or over suffering from fever or biological inflammation. Acute bacterial infection was assessed using biological identification and/or clinical and radiological data.

RESULTS

A total of 156 patients were included. Eighty-two (53%) patients suffered from acute bacterial infection (mean age (SD) 88.7 (5.9)). Low eosinophil count was independently associated with acute bacterial infection: OR [CI95%] 3.03 [1.04-9.37] and 6.08 [2.42-16.5] for eosinophil count 0-0.07 G/L and 0.07-0.172 G/L respectively (vs. eosinophil count > 0.172 G/L). Specificity and sensitivity for eosinophil count < 0.01 G/L and CIBLE score were 84%-49% and 72%-62%, respectively with equivalent AUCs (0.66 and 0.67).

CONCLUSION

Eosinophil count < 0.01 G/L is a simple, routinely used and inexpensive tool which can easily participate in antibiotic decisions for older adults. Further studies are needed to assess clinical benefits.

TRIAL REGISTRATION

The study was registered at Clinical trial.gov (NCT04363138-23/04/2020).

Syntaxin-4 and SNAP23 are involved in neutrophil degranulation, but not in the release of mitochondrial DNA during NET formation

Neutrophils are a specialized subset of white blood cells, which have the ability to store pre-formed mediators in their cytoplasmic granules. Neutrophils are well-known effector cells involved in host protection against pathogens through diverse mechanisms such as phagocytosis, degranulation, extracellular traps, and oxidative burst. In this study, we provide evidence highlighting the significance of the SNARE proteins syntaxin-4 and synaptosomal-associated protein (SNAP) 23 in the release of azurophilic granules, specific granules, and the production of reactive oxygen species in human neutrophils. In contrast, the specific blockade of either syntaxin-4 or SNAP23 did not prevent the release of mitochondrial dsDNA in the process of neutrophil extracellular trap (NET) formation. These findings imply that degranulation and the release of mitochondrial dsDNA involve at least partially distinct molecular pathways in neutrophils.

Eosinophils and tissue remodeling: Relevance to airway disease

The ability of human tissue to reorganize and restore its existing structure underlies tissue homeostasis in the healthy airways, but in disease can persist without normal resolution, leading to an altered airway structure. Eosinophils play a cardinal role in airway remodeling both in health and disease, driving epithelial homeostasis and extracellular matrix turnover. Physiological consequences associated with eosinophil-driven remodeling include impaired lung function and reduced bronchodilator reversibility in asthma, and obstructed airflow in chronic rhinosinusitis with nasal polyps. Given the contribution of airway remodeling to the development and persistence of symptoms in airways disease, targeting remodeling is an important therapeutic consideration. Indeed, there is early evidence that eosinophil attenuation may reduce remodeling and disease progression in asthma. This review provides an overview of tissue remodeling in both health and airway disease with a particular focus on eosinophilic asthma and chronic rhinosinusitis with nasal polyps, as well as the role of eosinophils in these processes and the implications for therapeutic interventions. Areas for future research are also noted, to help improve our understanding of the homeostatic and pathological roles of eosinophils in tissue remodeling, which should aid the development of targeted and effective treatments for eosinophilic diseases of the airways.

Assessment of common risk factors of diabetes and chronic kidney disease: a Mendelian randomization study

Background

The increasing prevalence of diabetes and its significant impact on mortality and morbidity rates worldwide has led to a growing interest in understanding its common risk factors, particularly in relation to chronic kidney disease (CKD). This research article aims to investigate the shared risk factors between type 1 diabetes (T1D), type 2 diabetes (T2D), and CKD using a Mendelian randomization (MR) design.

Methods

The study utilized genome-wide association study (GWAS) datasets for T1D, T2D, and CKD from the FinnGen research project. GWAS summary statistics datasets for 118 exposure traits were obtained from the IEU OpenGWAS database. MR analyses were conducted to examine the causal relationships between exposure traits and each of the three outcomes. Multiple methods, including inverse-variance weighted, weighted median, and MR-Egger, were employed for the MR studies.

Results

Phenome-wide MR analyses revealed that eosinophil percentage exhibited a significant and suggestive causal association with T1D and CKD, respectively, suggesting its potential as a shared risk factor for T1D and CKD. For T2D, 34 traits demonstrated significant associations. Among these 34 traits, 14 were also significantly associated with CKD, indicating the presence of common risk factors between T2D and CKD, primarily related to obesity, height, blood lipids and sex hormone binding globulin, blood pressure, and walking pace.

Conclusion

This research has uncovered the eosinophil percentage as a potential common risk factor for both T1D and CKD, while also identifying several traits, such as obesity and blood lipids, as shared risk factors for T2D and CKD. This study contributes to the understanding of the common risk factors between diabetes and CKD, emphasizing the need for targeted interventions to reduce the risk of these diseases.

The oxidative stress response of Streptococcus pneumoniae: its contribution to both extracellular and intracellular survival

Streptococcus pneumoniae is a gram-positive, aerotolerant bacterium that naturally colonizes the human nasopharynx, but also causes invasive infections and is a major cause of morbidity and mortality worldwide. This pathogen produces high levels of H2O2 to eliminate other microorganisms that belong to the microbiota of the respiratory tract. However, it also induces an oxidative stress response to survive under this stressful condition. Furthermore, this self-defense mechanism is advantageous in tolerating oxidative stress imposed by the host's immune response. This review provides a comprehensive overview of the strategies employed by the pneumococcus to survive oxidative stress. These strategies encompass the utilization of H2O2 scavengers and thioredoxins, the adaptive response to antimicrobial host oxidants, the regulation of manganese and iron homeostasis, and the intricate regulatory networks that control the stress response. Here, we have also summarized less explored aspects such as the involvement of reparation systems and polyamine metabolism. A particular emphasis is put on the role of the oxidative stress response during the transient intracellular life of Streptococcus pneumoniae, including coinfection with influenza A and the induction of antibiotic persistence in host cells.

Real-World Investigation of Eosinophilic-Associated Disease Overlap (REVEAL): Analysis of a US Claims Database

PURPOSE

The epidemiology of eosinophil-associated diseases (EADs) is not yet fully understood. While some studies have been conducted on stand-alone eosinophilic diseases, there is scarce evidence on the degree of overlap among rarer conditions.

METHODS

The retrospective Real-world inVestigation of Eosinophilic-Associated disease overLap (REVEAL) study used data from the Optum® Clinformatics® insurance claims database to describe and characterize disease overlap among 11 EADs: allergic bronchopulmonary aspergillosis, atopic dermatitis, chronic rhinosinusitis with nasal polyps, eosinophilic gastritis/gastroenteritis, eosinophilic granulomatosis with polyangiitis, eosinophilic esophagitis, bullous pemphigoid, chronic obstructive pulmonary disorder, chronic spontaneous urticaria, and non-cystic fibrosis bronchiectasis. Patient records with EADs of interest were identified between January 1, 2015, and June 30, 2018.

RESULTS

Overall, 1,326,645 patients were included; 74.4% had 1 EAD, 20.5% had ≥ 2 EADs, and 5.1% had ≥ 3 EADs. Higher rates of disease overlap were associated with older age. Higher blood eosinophil counts were also observed in patients with a greater number of overlapping conditions, suggesting a common role for eosinophilic inflammation in the pathogenesis of multiple diseases. Furthermore, greater disease overlap was associated with higher disease severity in most cohorts.

CONCLUSIONS

Results from this study have implications for quantifying unmet needs and can be used to inform treatment guidelines and raise the awareness of eosinophilic inflammation and EAD overlap among healthcare professionals from a range of disease specialties.

Influenza breakthrough infection in vaccinated mice is characterized by non-pathological lung eosinophilia

Eosinophils are important mediators of mucosal tissue homeostasis, anti-helminth responses, and allergy. Lung eosinophilia has previously been linked to aberrant Type 2-skewed T cell responses to respiratory viral infection and may also be a consequence of vaccine-associated enhanced respiratory disease (VAERD), particularly in the case of respiratory syncytial virus (RSV) and the formalin-inactivated RSV vaccine. We previously reported a dose-dependent recruitment of eosinophils to the lungs of mice vaccinated with alum-adjuvanted trivalent inactivated influenza vaccine (TIV) following a sublethal, vaccine-matched H1N1 (A/New Caledonia/20/1999; NC99) influenza challenge. Given the differential role of eosinophil subset on immune function, we conducted the investigations herein to phenotype the lung eosinophils observed in our model of influenza breakthrough infection. Here, we demonstrate that eosinophil influx into the lungs of vaccinated mice is adjuvant- and sex-independent, and only present after vaccine-matched sublethal influenza challenge but not in mock-challenged mice. Furthermore, vaccinated and challenged mice had a compositional shift towards more inflammatory eosinophils (iEos) compared to resident eosinophils (rEos), resembling the shift observed in ovalbumin (OVA)-sensitized allergic control mice, however without any evidence of enhanced morbidity or aberrant inflammation in lung cytokine/chemokine signatures. Furthermore, we saw a lung eosinophil influx in the context of a vaccine-mismatched challenge. Additional layers of heterogeneity in the eosinophil compartment were observed via unsupervised clustering analysis of flow cytometry data. Our collective findings are a starting point for more in-depth phenotypic and functional characterization of lung eosinophil subsets in the context of vaccine- and infection-induced immunity.

Prognostic Value of Routine Biomarkers in the Early Stage of COVID-19

Various biomarkers like certain complete blood cell count parameters and the derived ratios including neutrophil-lymphocyte ratio are commonly used to evaluate disease severity. Our study aimed to establish if baseline levels of complete blood cell count-derived biomarkers and CRP, measured before any treatment which can interfere with their values, could serve as a predictor of development of pneumonia and the need for hospitalization requiring oxygen therapy. We retrospectively analyzed the laboratory data of 200 consecutive patients without comorbidities, who denied usage of medications prior to blood analysis and visited a COVID-19 ambulance between October and December 2021. Multivariate regression analysis extracted older age, elevated CRP and lower eosinophil count as significant independent predictors of pneumonia (p = 0.003, p = 0.000, p = 0.046, respectively). Independent predictors of hospitalization were higher CRP (p = 0.000) and lower platelet count (p = 0.005). There was no significant difference in the neutrophil-lymphocyte and platelet-lymphocyte ratios between examined groups. Individual biomarkers such as platelet and eosinophil count might be better in predicting the severity of COVID-19 than the neutrophil-lymphocyte and platelet-lymphocyte ratios.

Platelets and mast cells promote pathogenic eosinophil recruitment during invasive fungal infection via the 5-HIAA-GPR35 ligand-receptor system

Cryptococcus neoformans is the leading cause of fungal meningitis and is characterized by pathogenic eosinophil accumulation in the context of type-2 inflammation. The chemoattractant receptor GPR35 is expressed by granulocytes and promotes their migration to the inflammatory mediator 5-hydroxyindoleacetic acid (5-HIAA), a serotonin metabolite. Given the inflammatory nature of cryptococcal infection, we examined the role of GPR35 in the circuitry underlying cell recruitment to the lung. GPR35 deficiency dampened eosinophil recruitment and fungal growth, whereas overexpression promoted eosinophil homing to airways and fungal replication. Activated platelets and mast cells were the sources of GPR35 ligand activity and pharmacological inhibition of serotonin conversion to 5-HIAA, or genetic deficiency in 5-HIAA production by platelets and mast cells resulted in more efficient clearance of Cryptococcus. Thus, the 5-HIAA-GPR35 axis is an eosinophil chemoattractant receptor system that modulates the clearance of a lethal fungal pathogen, with implications for the use of serotonin metabolism inhibitors in the treatment of fungal infections.

Treatment of Urticaria caused by severe cryptosporidiosis in a 17-month-old child - a case report

BACKGROUND

Cryptosporidium is an intracellular protozoan that causes gastrointestinal symptoms in humans and animals. In immunocompromised patients and children under 5 years of age, the infection is severe and can be life-threatening due to severe diarrhea.

CASE PRESENTATION

We report a case of urticaria associated with Cryptosporidium in a 17-month-old female Iranian child. The patient had moderate diarrhea (> 3 loose, watery stools but not more than 10 diarrhea stools in a day), weight loss, and acute urticarial (rash clears completely within 6 weeks). Since the child's father worked in livestock farming, the parasite may have been transferred from the cow or calve to the house and the child. Several Cryptosporidium oocysts were detected in the modified acid-fast staining of the child's stool sample. The patient was successfully treated with nitazoxanide (100 mg twice daily) and became negative for parasites three days after treatment and one week after discharge from the hospital. The child was observed to produce < 3 loose stools in the previous 24 h after 1-week post-treatment and after 6 months of follow-up.

CONCLUSION

A number of parasites are associated with urticaria, but to our knowledge, there is no information on Cryptosporidium-induced urticaria. Therefore, our result may be evidence for the role of this parasite in the development of urticaria if other causes such as food allergies, autoimmune diseases and etc. don't role in urticaria.

Eosinophils as potential biomarkers in respiratory viral infections

Eosinophils are bone marrow-derived granulocytes that, under homeostatic conditions, account for as much as 1-3% of peripheral blood leukocytes. During inflammation, eosinophils can rapidly expand and infiltrate inflamed tissues, guided by cytokines and alarmins (such as IL-33), adhesion molecules and chemokines. Eosinophils play a prominent role in allergic asthma and parasitic infections. Nonetheless, they participate in the immune response against respiratory viruses such as respiratory syncytial virus and influenza. Notably, respiratory viruses are associated with asthma exacerbation. Eosinophils release several molecules endowed with antiviral activity, including cationic proteins, RNases and reactive oxygen and nitrogen species. On the other hand, eosinophils release several cytokines involved in homeostasis maintenance and Th2-related inflammation. In the context of SARS-CoV-2 infection, emerging evidence indicates that eosinophils can represent possible blood-based biomarkers for diagnosis, prognosis, and severity prediction of disease. In particular, eosinopenia seems to be an indicator of severity among patients with COVID-19, whereas an increased eosinophil count is associated with a better prognosis, including a lower incidence of complications and mortality. In the present review, we provide an overview of the role and plasticity of eosinophils focusing on various respiratory viral infections and in the context of viral and allergic disease comorbidities. We will discuss the potential utility of eosinophils as prognostic/predictive immune biomarkers in emerging respiratory viral diseases, particularly COVID-19. Finally, we will revisit some of the relevant methods and tools that have contributed to the advances in the dissection of various eosinophil subsets in different pathological settings for future biomarker definition.

The interaction of Schistosoma mansoni infection with diabetes mellitus and obesity in mice

Human schistosomiasis is one of the most prevalent parasitic diseases worldwide. Various host factors can affect the host-parasite interactions. Therefore, the aim of the present work was to determine the parasitological, histopathological, biochemical, and immunological status of Schistosoma mansoni-infected hosts with metabolic disorders to identify the underlying possible mechanisms of these comorbidities. The study animals were divided into four groups. Group I represented the control groups, namely, the normal control group, the S. mansoni-infected control group, and the noninfected type 1 diabetes (T1DM), type 2 diabetes (T2DM), and obesity groups. The mice of the other three groups underwent induction of T1DM (Group II), T2DM (Group III) and obesity (Group IV) before being infected with S. mansoni. All mice were subjected to body weight measurement, blood glucose and insulin assessment, parasitological evaluation of adult worm count, tissue egg count and intestinal oogram. Histopathological and immunohistochemical study using anti-glial fibrillary acidic protein (GFAP) in hepatic stellate cells (HSCs) and image analysis of Masson's trichrome-stained liver sections using ImageJ (Fiji) software were carried out. Additionally, immunological analysis of tumour necrosis factor (TNF) beta, interleukin-5 (IL-5), IL-10, Forkhead box P3 (FOXP3) and pentraxin 3 (PTX3) levels besides biochemical study of total lipid profile were evaluated. The present study revealed a significant increase in the adult worm count and tissue egg output in the obesity group compared to the infected control group. The oogram of counted eggs showed prevalence of immature eggs in T1DM group, while T2DM and obese groups showed prevalence of mature eggs. The fibrosis area percentage showed significant increase in T2DM and obese groups while it was decreased in T1DM group in comparison to infected control group. Our data also showed significant increase in the levels of TNF-β, IL-5, PTX3 in T1DM, T2DM and obesity groups in comparison to infected control group, whilst the levels of FOXP3 and IL-10 were increased in the infected groups in comparison to their noninfected controls. Moreover, infected T1DM, T2DM and obesity groups showed higher blood glucose and lipid profile in comparison to the infected control group. However, these parameters were improved in comparison to their noninfected controls. In sum, induction of T2DM and obesity increased tissue egg counts, mature egg percentage, and fibrosis density, while schistosome infection induced changes in the lipid profile and blood glucose levels in infected diabetic and obese groups and impacted favorably insulin levels in obese mice. By better understanding the complexities of host-parasite interactions, efforts to reduce the burden of these debilitating diseases can be improved.

Clinical Implications of Longitudinal Blood Eosinophil Counts in Patients With Severe Asthma

BACKGROUND

The stability and variability of blood eosinophil counts (BECs) to phenotype patients with severe asthma is not fully understood.

OBJECTIVE

This post hoc, longitudinal, pooled analysis of placebo-arm patients from 2 phase 3 studies evaluated the clinical implications of BEC stability and variability in moderate-to-severe asthma.

METHODS

This analysis included patients from SIROCCO and CALIMA who received maintenance medium- to high-dosage inhaled corticosteroids plus long-acting β2-agonists; 2:1 patients with BECs of 300 cells/μL or higher and less than 300 cells/μL were enrolled. The BECs were measured 6 times over 1 year in a centralized laboratory. Exacerbations, lung function, and Asthma Control Questionnaire 6 scores were documented across patients grouped by BEC (<300 cells/μL or ≥300 cells/μL) and variability (<80% or ≥80% BECs less than or greater than 300 cells/μL).

RESULTS

Among 718 patients, 42.2% (n = 303) had predominantly high, 30.9% (n = 222) had predominantly low, and 26.9% (n = 193) had variable BECs. Prospective exacerbation rates (mean ± SD) were significantly greater in patients with predominantly high (1.39 ± 2.20) and variable (1.41 ± 2.09) BECs versus predominantly low (1.05 ± 1.66) BECs. Similar results were observed for the number of exacerbations while on placebo.

CONCLUSIONS

Although patients with variable BECs had intermittently high and low BECs, they experienced similar exacerbation rates to the predominantly high group, which were greater than those in the predominantly low group. A high BEC supports an eosinophilic phenotype in clinical settings without additional measurements, whereas a low BEC requires repeated measurements because it could reflect intermittently high or predominantly low BECs.

Strongyloidiasis-related lung involvement: too much of a bad thing

PURPOSE OF REVIEW

Strongyloidiasis is a soil-transmitted helminthiasis, a neglected tropical disease that affects 300-900 million individuals globally. Strongyloides stercoralis is associated with cutaneous, respiratory, and gastrointestinal clinical manifestations. Chronicity is due to an autoinfective cycle, and host immunosuppression can lead to severe and fatal disease. Lung involvement is significant in severe strongyloidiasis, and Strongyloides has a complex association with a number of lung diseases, which will be discussed in this review.

RECENT FINDINGS

The treatment of chronic lung diseases such as asthma and chronic obstructive pulmonary disease with corticosteroids is an important risk factor for Strongyloides hyperinfection syndrome (SHS)/disseminated strongyloidiasis. The use of corticosteroids in the treatment of coronavirus disease 2019 (COVID-19) and potentially COVID-19-induced eosinopenia are risk factors for severe strongyloidiasis. Recent findings have demonstrated a significant immunomodulatory role of Strongyloides in both latent and active pulmonary tuberculosis associated to an impaired immune response and poor outcomes in active pulmonary tuberculosis.

SUMMARY

Strongyloides lung involvement is a common finding in severe infection. Prompt recognition of Strongyloides infection as well as prevention of severe disease by screening or presumptive treatment are important goals in order to improve Strongyloides outcomes in at-risk population.

The multidisciplinary approach to eosinophilia

Eosinophilic granulocytes are normally present in low numbers in the bloodstream. Patients with an increased number of eosinophilic granulocytes in the differential count (eosinophilia) are common and can pose a clinical challenge because conditions with eosinophilia occur in all medical specialties. The diagnostic approach must be guided by a thorough medical history, supported by specific tests to guide individualized treatment. Neoplastic (primary) eosinophilia is identified by one of several unique acquired genetic causes. In contrast, reactive (secondary) eosinophilia is associated with a cytokine stimulus in a specific disease, while idiopathic eosinophilia is a diagnosis by exclusion. Rational treatment is disease-directed in secondary cases and has paved the way for targeted treatment against the driver in primary eosinophilia, whereas idiopathic cases are treated as needed by principles in eosinophilia originating from clonal drivers. The vast majority of patients are diagnosed with secondary eosinophilia and are managed by the relevant specialty-e.g., rheumatology, allergy, dermatology, gastroenterology, pulmonary medicine, hematology, or infectious disease. The overlap in symptoms and the risk of irreversible organ involvement in eosinophilia, irrespective of the cause, warrants that patients without a diagnostic clarification or who do not respond to adequate treatment should be referred to a multidisciplinary function anchored in a hematology department for evaluation. This review presents the pathophysiology, manifestations, differential diagnosis, diagnostic workup, and management of (adult) patients with eosinophilia. The purpose is to place eosinophilia in a clinical context, and therefore justify and inspire the establishment of a multidisciplinary team of experts from diagnostic and clinical specialties at the regional level to support the second opinion. The target patient population requires highly specialized laboratory analysis and therapy and occasionally has severe eosinophil-induced organ dysfunction. An added value of a centralized, clinical function is to serve as a platform for education and research to further improve the management of patients with eosinophilia. Primary and idiopathic eosinophilia are key topics in the review, which also address current research and discusses outstanding issues in the field.

Management of eosinophil-associated inflammatory diseases: the importance of a multidisciplinary approach

Elevated eosinophil counts in blood and tissue are a feature of many pathological processes. Eosinophils can migrate and accumulate in a wide variety of tissues and, by infiltrating a target organ, can mediate the development of several inflammatory diseases. The normalization of eosinophilia is a common biomarker of a treatable trait and can also be used as a prognostic and predictive biomarker since it implies a reduction in type 2 inflammation that contributes to disease pathogenesis. Biological therapies targeting this cell type and its proinflammatory mediators have been shown to be effective in the management of a number of eosinophilic diseases, and for this reason they constitute a potential common strategy in the treatment of patients with various multimorbidities that present with type 2 inflammation. Various biological options are available that could be used to simultaneously treat multiple target organs with a single drug, bearing in mind the need to offer personalized treatments under the umbrella of precision medicine in all patients with eosinophil-associated diseases (EADs). In addition to reviewing these issues, we also discuss a series of perspectives addressing the management of EAD patients from a multidisciplinary approach, with the collaboration of health professionals from different specialties who manage the different multimorbidities that frequently occur in these patients. We examine the basic principles of care that this multidisciplinary approach must cover and present a multidisciplinary expert opinion regarding the ideal management of patients with EADs, from diagnosis to therapeutic approach and follow-up.

White blood cells in a healthy adolescent population according to social and health characteristics

BACKGROUND

The immune system constitutes a sensory system both for heritable and non-heritable factors. Among the latter, social and environmental determinants of health may influence and shape the immune system in early life. To study the relationship between leukocytes and determinants of health in adolescence, we assessed total and differential white blood cells (WBC) according to social and environmental determinants of health in a healthy adolescent population.

METHODS

As part of the population-based cohort Epidemiological Health Investigation of Teenagers in Porto (EPITeen), 1213 adolescents were evaluated at the age of 13. Total and differential WBC were evaluated through a venous blood sample using an automated blood counter (Sysmex®XE-5000, Hyogo, Japan). Sociodemographic, behavioral, and clinical data were collected through self-administered questionnaires.

RESULTS

Participants with better socioeconomic conditions (enrolled at private schools or higher parental education) had significantly lower total WBC levels, and the latter showed a lower percentage of neutrophils and higher percentage of lymphocytes. Those who practiced sports had significantly lower total WBC levels and neutrophil percentage, as well as a significantly higher percentage of eosinophils and lymphocytes. Adolescents with chronic disease, chronic medication, or allergic diseases had a significantly higher percentage of eosinophils and a lower percentage of monocytes. With increasing body mass index and systemic inflammation, we found a significant increase in total WBC levels.

CONCLUSION

WBC linked to different immune response patterns are associated with several social and environmental determinants of health in adolescence.

Bilateral pulmonary embolism associated with peripheral blood eosinophilia and positive antiphospholipid antibodies in a patient with cellulitis

Key Clinical Message

This report described the pathophysiology, diagnostic workup, and management of thrombosis possibly associated with peripheral blood eosinophilia and transient positive antiphospholipid antibodies in the setting of cellulitis.

Abstract

Peripheral blood eosinophilia is a risk factor for thrombosis and the presence of other prothrombotic factors such as antiphospholipid antibodies can potentiate that risk. The authors present a case of acute pulmonary embolism which developed at the peak of eosinophilia, later found to have transient positive antiphospholipid antibodies in a male patient with right lower limb cellulitis and a history of intravenous drug abuse. This report illustrates the pathophysiology, diagnosis workup, and therapeutic options of thrombosis possibly associated with peripheral blood eosinophilia and positive antiphospholipid antibodies, which include anticoagulants, corticosteroids, and immunosuppressants. Clinicians should be aware of this possible association which may guide the choice and duration of anticoagulants. Although direct oral anticoagulants are effective anticoagulants in various thromboembolic events, studies showed unfavorable outcomes for their use in antiphospholipid syndrome.