Eosinophils from Physiology to Disease: A Comprehensive Review

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.

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.

The Role of Benralizumab in Eosinophilic Immune Dysfunctions: A Case Report-Based Literature Review

In the past years, the knowledge of eosinophils playing a primary pathophysiologic role in several associated conditions has led to the development of biologics targeting therapies aiming at normalizing the immune response, reducing chronic inflammation, and preventing tissue damage. To better illustrate the potential relationship between different eosinophilic immune dysfunctions and the effects of biological therapies in this scenario, here, we present a case of a 63-year-old male first referred to our department in 2018 with a diagnosis of asthma, polyposis, and rhinosinusitis and presenting a suspicion of nonsteroidal anti-inflammatory drugs' allergy. He also had a past medical history of eosinophilic gastroenteritis/duodenitis (eosinophilia counts >50 cells/high-power field HPF). The use of multiple courses of corticosteroid therapy failed to completely control these conditions. In October 2019, after starting benralizumab (an antibody directed against the alpha chain of the IL-5 cytokine receptor) as add-on treatment for severe eosinophilic asthma, important clinical improvements were reported both on the respiratory (no asthma exacerbations) and gastrointestinal systems (eosinophilia count 0 cells/HPF). Patients' quality of life also increased. Since June 2020, systemic corticosteroid therapy was reduced without worsening of gastrointestinal symptoms or eosinophilic inflammation. This case warns of the importance of early recognition and appropriate individualized treatment of eosinophilic immune dysfunctions and suggests the conduction of further larger studies on the use of benralizumab in gastrointestinal syndromes aiming at better understanding its relying mechanisms of action in the intestinal mucosa.

Unmet needs and evidence gaps in hypereosinophilic syndrome and eosinophilic granulomatosis with polyangiitis

Hypereosinophilic syndrome (HES) and eosinophilic granulomatosis with polyangiitis (EGPA) are rare systemic inflammatory disorders with overlapping symptoms, elevated eosinophil counts, and heterogenous clinical presentations. Although progress has been made in recent years, there are substantial gaps in our understanding of the pathologic mechanisms involved in these diseases, as well as numerous unmet needs relating to both diagnosis and patient management. For example, in most cases of HES, the underlying cause of hypereosinophilia is unknown, while in EGPA, although a polygenic genetic susceptibility has been found, understanding of the pathogenic mechanisms remains largely elusive. Delineating differences between certain disease variants may be challenging, and there are no reliable predictive markers of disease course. In addition, the current diagnostic criteria for HES and classification criteria for EGPA are not easy to implement in a nonspecialist setting, and specialist referral pathways need to be signposted more clearly. Furthermore, disease-specific activity scores need to be developed to aid the assessment of treatment effects, and improved biomarkers are needed to aid with treatment stratification. In this review, we outline the limitations of our current understanding of HES and EGPA and highlight areas for future work, which ultimately should help improve patient management and outcomes.

The role of anti-eosinophilic therapies in eosinophilic granulomatosis with polyangiitis: a systematic review

Eosinophilic granulomatosis with polyangiitis (EGPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, mostly affecting small-sized arteries and usually occurring in patients with an allergic background. Eosinophils seem to play a significant role in the pathogenesis of the disease and, therefore, biologics targeting interleukin 5 (IL5), a cytokine tightly linked to eosinophils, have emerged as a promising therapeutic tool. A systematic review of Medline was conducted from 2007 to 2022 to search for data regarding the use of anti-IL5 therapies in patients with EGPA. Ongoing or unpublished trials were also searched in ClinicalTrials.gov and the World Health Organization trials portal. The efficacy and safety of mepolizumab, an anti-IL5 monoclonal antibody (mAb), was confirmed by a randomized controlled trial (RCT), although a significant proportion of patients did not respond to this treatment. Other studies showed that both doses of 100 mg and 300 mg of mepolizumab are almost equally effective in EGPA. Benralizumab, an anti-IL5 receptor mAb has preliminary promising results and an RCT is planned to be conducted. Apart from their clinical efficacy in EGPA, anti-IL5 therapies may have steroid-sparing properties. Anti-IL5 therapies seem to be effective and safe in patients with refractory/relapsing EGPA and can be used as a steroid-sparing treatment. Nevertheless, more research is needed to clarify the pathophysiology of the disease; this may potentially lead to the identification of biomarkers to pinpoint patients most likely to respond to anti-IL5-blockade.

Subsets of Eosinophils in Asthma, a Challenge for Precise Treatment

The existence of eosinophils was documented histopathologically in the first half of the 19th century. However, the term “eosinophils” was first used by Paul Ehrlich in 1878. Since their discovery and description, their existence has been associated with asthma, allergies, and antihelminthic immunity. Eosinophils may also be responsible for various possible tissue pathologies in many eosinophil-associated diseases. Since the beginning of the 21st century, the understanding of the nature of this cell population has undergone a fundamental reassessment, and in 2010, J. J. Lee proposed the concept of “LIAR” (Local Immunity And/or Remodeling/Repair), underlining the extensive immunoregulatory functions of eosinophils in the context of health and disease. It soon became apparent that mature eosinophils (in line with previous morphological studies) are not structurally, functionally, or immunologically homogeneous cell populations. On the contrary, these cells form subtypes characterized by their further development, immunophenotype, sensitivity to growth factors, localization, role and fate in tissues, and contribution to the pathogenesis of various diseases, including asthma. The eosinophil subsets were recently characterized as resident (rEos) and inflammatory (iEos) eosinophils. During the last 20 years, the biological therapy of eosinophil diseases, including asthma, has been significantly revolutionized. Treatment management has been improved through the enhancement of treatment effectiveness and a decrease in the adverse events associated with the formerly ultimately used systemic corticosteroids. However, as we observed from real-life data, the global treatment efficacy is still far from optimal. A fundamental condition, “sine qua non”, for correct treatment management is a thorough evaluation of the inflammatory phenotype of the disease. We believe that a better understanding of eosinophils would lead to more precise diagnostics and classification of asthma subtypes, which could further improve treatment outcomes. The currently validated asthma biomarkers (eosinophil count, production of NO in exhaled breath, and IgE synthesis) are insufficient to unveil super-responders among all severe asthma patients and thus give only a blurred picture of the adepts for treatment. We propose an emerging approach consisting of a more precise characterization of pathogenic eosinophils in terms of the definition of their functional status or subset affiliation by flow cytometry. We believe that the effort to find new eosinophil-associated biomarkers and their rational use in treatment algorithms may ameliorate the response rate to biological therapy in patients with severe asthma.

Hypothiocyanite and host-microbe interactions

The pseudohypohalous acid hypothiocyanite/hypothiocyanous acid (OSCN^- /HOSCN) has been known to play an antimicrobial role in mammalian immunity for decades. It is a potent oxidant that kills bacteria but is non-toxic to human cells. Produced from thiocyanate (SCN^- ) and hydrogen peroxide (H₂ O₂ ) in a variety of body sites by peroxidase enzymes, HOSCN has been explored as an agent of food preservation, pathogen killing, and even improved toothpaste. However, despite the well-recognized antibacterial role HOSCN plays in host-pathogen interactions, little is known about how bacteria sense and respond to this oxidant. In this work, we will summarize what is known and unknown about HOSCN in innate immunity and recent advances in understanding the responses that both pathogenic and non-pathogenic bacteria mount against this antimicrobial agent, highlighting studies done with three model organisms, Escherichia coli, Streptococcus spp., and Pseudomonas aeruginosa.

Eosinophils protect against pulmonary hypertension through 14-HDHA and 17-HDHA

BACKGROUND

Pulmonary hypertension (PH) is a life-threatening disease featuring pulmonary vessel remodelling and perivascular inflammation. The effect, if any, of eosinophils (EOS) on the development of PH remains unclear.

METHODS

EOS infiltration and chemotaxis were investigated in peripheral blood and lung tissues from pulmonary arterial hypertension (PAH) patients without allergic history and from sugen/hypoxia-induced PH mice. The role of EOS deficiency in PH development was investigated using GATA1-deletion (ΔdblGATA) mice and anti-interleukin 5 antibody-treated mice and rats. Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was conducted to identify the critical oxylipin molecule(s) produced by EOS. Culture supernatants and lysates of EOS were collected to explore the mechanisms in co-culture cell experiments.

RESULTS

There was a lower percentage of EOS in peripheral blood but higher infiltration in lung tissues from PAH patients and PH mice. PAH/PH lungs showed increased EOS-related chemokine expression, mainly C-C motif chemokine ligand 11 derived from adventitial fibroblasts. EOS deficiency aggravated PH in rodents, accompanied by increased neutrophil and monocyte/macrophage infiltration. EOS highly expressed arachidonate 15-lipoxygenase (ALOX15). 14-hydroxy docosahexaenoic acid (14-HDHA) and 17-HDHA were critical downstream oxylipins produced by EOS, which showed anti-inflammatory effects on recruitment of neutrophils and monocytes/macrophages through N-formyl peptide receptor 2. They also repressed pulmonary artery smooth muscle cell (PASMC) proliferation by activating peroxisome proliferator-activated receptor γ and blunting Stat3 phosphorylation.

CONCLUSIONS

In PH development without external stimuli, peripheral blood exhibits a low EOS level. EOS play a protective role by suppressing perivascular inflammation and maintaining PASMC homeostasis via 14/17-HDHA.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): Focus on the Pathophysiological and Diagnostic Role of Viruses

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a heterogeneous, multiorgan and potentially life-threatening drug-hypersensitivity reaction (DHR) that occurs several days or weeks after drug initiation or discontinuation. DHRs constitute an emerging issue for public health, due to population aging, growing multi-organ morbidity, and subsequent enhanced drug prescriptions. DRESS has more consistently been associated with anticonvulsants, allopurinol and antibiotics, such as sulphonamides and vancomycin, although new drugs are increasingly reported as culprit agents. Reactivation of latent infectious agents such as viruses (especially Herpesviridae) plays a key role in prompting and sustaining aberrant T-cell and eosinophil responses to drugs and pathogens, ultimately causing organ damage. However, the boundaries of the impact of viral agents in the pathophysiology of DRESS are still ill-defined. Along with growing awareness of the multifaceted aspects of immune perturbation caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the ongoing SARS-CoV-2-related disease (COVID-19) pandemic, novel interest has been sparked towards DRESS and the potential interactions among antiviral and anti-drug inflammatory responses. In this review, we summarised the most recent evidence on pathophysiological mechanisms, diagnostic approaches, and clinical management of DRESS with the aim of increasing awareness on this syndrome and possibly suggesting clues for future research in this field.

The BNT162b2 mRNA COVID-19 Vaccine Increases the Contractile Sensitivity to Histamine and Parasympathetic Activation in a Human Ex Vivo Model of Severe Eosinophilic Asthma

The BNT162b2 COVID-19 vaccine is composed of lipid-nanoparticles (LNP) containing the mRNA that encodes for SARS-CoV-2 spike glycoprotein. Bronchospasm has been reported as an early reaction after COVID-19 mRNA vaccines in asthmatic patients. The aim of this study was to investigate the acute impact of BNT162b2 in a human ex vivo model of severe eosinophilic asthma. Passively sensitized human isolated bronchi were challenged with the platelet-activating factor to reproduce ex vivo the hyperresponsiveness of airways of patients suffering from severe eosinophilic asthma. BNT162b2 was tested on the contractile sensitivity to histamine and parasympathetic activation via electrical field stimulation (EFS); some experiments were performed after mRNA denaturation. BNT162b2 increased the resting tone (+11.82 ± 2.27%) and response to histamine in partially contracted tissue (+42.97 ± 9.64%) vs. the control (p < 0.001); it also shifted the concentration-response curve to histamine leftward (0.76 ± 0.09 logarithm) and enhanced the response to EFS (+28.46 ± 4.40%) vs. the control. Denaturation did not significantly modify (p > 0.05) the effect of BNT162b2. BNT162b2 increases the contractile sensitivity to histamine and parasympathetic activation in hyperresponsive airways, a detrimental effect not related to the active component but to some excipient. A possible candidate for the bronchospasm elicited by BNT162b2 could be the polyethylene glycol/macrogol used to produce LNP.

Evaluation of myocardial performance by serial speckle tracking echocardiography in diagnosis and follow-up of a patient with eosinophilic myocarditis

BACKGROUND

Speckle tracking echocardiography (STE) has been used as an adjunct diagnostic modality in patients with eosinophilic myocarditis. Its serial dynamic nature, however, has never been reported before.

CASE PRESENTATION

A 17-year-old boy presented in cardiogenic shock state. His full blood count revealed an absolute eosinophilic count of 11.18 × 10³/μL. An emergency 2D echocardiogram (2DE) showed global left ventricular hypokinesia with LVEF = 9.0% by Simpson's method and a large amount of pericardial effusion. STE showed a global longitudinal strain (GLS) of - 4.1%. Because of his poor clinical status and presence of marked hypereosinophilia and the possibility of eosinophilic myocarditis (EM), parenteral pulse therapy with methylprednisolone and inotropes was started with subsequent improvement within the next 48 h. Over the next few days, he had his first cardiovascular magnetic resonance imaging (CMR), which showed late gadolinium enhancement (LGE) in different cardiac regions. After two weeks of therapy, he left the hospital in a stable condition, with LVEF = 38.0%, and GLS = - 13.9%. He did well during his two months of outpatient follow-ups and was found to have an absolute eosinophil count of 0.0% on several occasions. Unfortunately, he was re-admitted because of treatment non-compliance with almost the same, albeit milder, symptoms. The WBC count was 18.1 × 10³ per microliter, and the eosinophilic count was 5.04 × 10³/μL (28%). Heart failure treatment and high-dose prednisolone were started. After 15 days of admission, he got better and was discharged. During both hospital admissions and several months of follow-up, he had multiple 2DEs, STE, and two CMR studies. None of his STEs were identical to the prior studies and were dynamic with frequent wax and wanes throughout the admissions and follow-ups. Thus a single admission-time STE study was not sufficient enough to properly predict the patient's outcome. Follow-up STEs showed new sites of myocardial involvement despite the absence of eosinophilia.

CONCLUSION

The use of STE in this patient, proved to have an added value in the evaluation and stratification of the left ventricular function in patients with EM and can be used as a diagnostic adjunct to CMR for diagnosis of EM.

Delayed Drug Hypersensitivity Reactions: Molecular Recognition, Genetic Susceptibility, and Immune Mediators

Drug hypersensitivity reactions are classified into immediate and delayed types, according to the onset time. In contrast to the immediate type, delayed drug hypersensitivity mainly involves T lymphocyte recognition of the drug antigens and cell activation. The clinical presentations of such hypersensitivity are various and range from mild reactions (e.g., maculopapular exanthema (MPE) and fixed drug eruption (FDE)), to drug-induced liver injury (DILI) and severe cutaneous adverse reactions (SCARs) (e.g., Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP)). The common culprits of delayed drug hypersensitivity include anti-epileptics, antibiotics, anti-gout agents, anti-viral drugs, etc. Delayed drug hypersensitivity is proposed to be initiated by different models of molecular recognition, composed of drug/metabolite antigen and endogenous peptide, HLA presentation, and T cell receptor (TCR) interaction. Increasing the genetic variants of HLA loci and drug metabolic enzymes has been identified to be responsible for delayed drug hypersensitivity. Furthermore, preferential TCR clonotypes, and the activation of cytotoxic proteins/cytokines/chemokines, are also involved in the pathogenesis of delayed drug hypersensitivity. This review provides a summary of the current understanding of the molecular recognition, genetic susceptibility, and immune mediators of delayed drug hypersensitivity.

Bullous pemphigoid: The role of type 2 inflammation in its pathogenesis and the prospect of targeted therapy

Bullous pemphigoid (BP) is an autoimmune disease that mainly occurs in the elderly, severely affecting their health and life quality. Traditional therapy for BP is mainly based on the systemic use of corticosteroids, but long-term use of corticosteroids results in a series of side effects. Type 2 inflammation is an immune response largely mediated by group 2 innate lymphoid cells, type 2 T helper cells, eosinophils, and inflammatory cytokines, such as interleukin (IL)-4, IL-5 and IL-13. Among patients with BP, the levels of immunoglobulin E and eosinophils are significantly increased in the peripheral blood and skin lesions, suggesting that the pathogenesis is tightly related to type 2 inflammation. To date, various targeted drugs have been developed to treat type 2 inflammatory diseases. In this review, we summarize the general process of type 2 inflammation, its role in the pathogenesis of BP and potential therapeutic targets and medications related to type 2 inflammation. The content of this review may contribute to the development of more effective drugs with fewer side effects for the treatment of BP.

The association between eosinophil count, serum lipids and metabolic syndrome in Taiwanese

BACKGROUND

Eosinophil count, dyslipidemia, and metabolic syndrome (MetS) are associated with systemic inflammation. We conducted this large population-based study to investigate the association between elevated eosinophil count, serum lipids, and MetS in the Taiwanese population.

METHODS

A cross-sectional study of 10,357 adults who underwent health checkups at Shin Kong Wu Ho-Su Memorial Hospital in Taiwan between January 2006 and December 2016 was conducted. MetS was defined according to criteria modified by the International Diabetes Federation specifically for the Chinese population. The measurement of serum lipids included high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-I (ApoA-I), and apolipoprotein B (ApoB). Pearson's correlation and linear regression were used to determine the association of eosinophil count with waist circumference, blood pressure, fasting glucose, and serum lipids. Multivariate logistic regression analysis was used to determine the odds ratio of MetS and abnormal serum lipid levels in each eosinophil count quartile.

RESULTS

Eosinophil count was positively associated with triglycerides levels and negatively associated with HDL-C levels; however, it was not significantly associated with ApoA-I and ApoB. The odds ratio of MetS increased significantly across eosinophil count quartiles. The adjusted odds ratios of MetS for the second, third, and fourth quartiles were 1.28, 1.38, and 1.42, respectively, with reference to the first quartile.

CONCLUSIONS

High eosinophil count is an independent risk factor for MetS. Hypertriglyceridemia and hypo-HDL-cholesterolemia might partly contribute to this result.

Emerging applications of nanotechnology in context to immunology: A comprehensive review

Numerous benefits of nanotechnology are available in many scientific domains. In this sense, nanoparticles serve as the fundamental foundation of nanotechnology. Recent developments in nanotechnology have demonstrated that nanoparticles have enormous promise for use in almost every field of life sciences. Nanoscience and nanotechnology use the distinctive characteristics of tiny nanoparticles (NPs) for various purposes in electronics, fabrics, cosmetics, biopharmaceutical industries, and medicines. The exclusive physical, chemical, and biological characteristics of nanoparticles prompt different immune responses in the body. Nanoparticles are believed to have strong potential for the development of advanced adjuvants, cytokines, vaccines, drugs, immunotherapies, and theranostic applications for the treatment of targeted bacterial, fungal, viral, and allergic diseases and removal of the tumor with minimal toxicity as compared to macro and microstructures. This review highlights the medical and non-medical applications with a detailed discussion on enhanced and targeted natural and acquired immunity against pathogens provoked by nanoparticles. The immunological aspects of the nanotechnology field are beyond the scope of this Review. However, we provide updated data that will explore novel theragnostic immunological applications of nanotechnology for better and immediate treatment.