Receptor for Advanced Glycation End Product (RAGE) Modulates Inflammation During Feeding of the Hard Tick, Haemaphysalis longicornis in Mice.

Ticks are notorious blood-sucking ectoparasites that affect both humans and animals. They serve as a unique vector of various deadly diseases. Here, we have shown the roles of the receptor for advanced glycation end products (RAGE) during repeated infestations by the tick Haemaphysalis longicornis using RAGE-/- mice. In primary infestation, a large blood pool developed, which was flooded with numerous RBCs, especially during the rapid feeding phase of the tick both in wild-type (wt) and RAGE-/- mice. Very few inflammatory cells were detected around the zones of haemorrhage in the primary infestations. However, the number of inflammatory cells gradually increased in the subsequent tick infestations, and during the third infestations, the number of inflammatory cells reached to the highest level (350.3 ± 16.8 cells/focus). The site of attachment was totally occupied by the inflammatory cells in wt mice, whereas very few cells were detected at the ticks' biting sites in RAGE-/- mice. RAGE was highly expressed during the third infestation in wt mice. In the third infestation, infiltration of CD44+ lymphocytes, eosinophils and expression of S100A8 and S100B significantly increased at the biting sites of ticks in wt, but not in RAGE-/- mice. In addition, peripheral eosinophil counts significantly increased in wt but not in RAGE-/- mice. Taken together, our study revealed that RAGE-mediated inflammation and eosinophils played crucial roles in the tick-induced inflammatory reactions.

Eosinophil-derived extracellular vesicles: isolation and classification techniques and implications for disease pathophysiology.

Eosinophils are leukocytes characterized by their ability to release granule content that is highly rich in enzymes and proteins. Besides the anti-helminthic, bactericidal, and antiviral properties of eosinophils and their secretory granules, these also play a prominent role in the pathophysiology of diseases like asthma, eosinophilic esophagitis, and other hypereosinophilic conditions by causing tissue damage and airway hyperresponsiveness. Although this cell was first recognized mainly for its capacity to release granule content, nowadays other capabilities such as cytokine secretion have been linked to its physiology, and research has found that eosinophils are not only involved in innate immunity, but also as orchestrators of immune responses. Nearly 10 years ago, eosinophil-derived extracellular vesicles (EVs) were first described; since then, the EV field has grown exponentially, revealing their vital roles in intracellular communication. In this review, we synthesize current knowledge on eosinophil-derived EVs, beginning with a description of what they are and what makes them important regulators of disease, followed by an account of the methodologies used to isolate and characterize EVs. We also summarize current understanding of eosinophil-derived vesicles functionality, especially in asthma, the disease in which eosinophil-derived EVs have been most widely studied, describing how they modulate the role of eosinophils themselves (through autocrine signaling) and the way they affect airway structural cells and airway remodeling. Deeper understanding of this cell type could lead to novel research in eosinophil biology, its role in other diseases, and possible use of eosinophil-derived EVs as therapeutic targets.

Eosinophils and chronic obstructive pulmonary diseases (COPD) in hospitalized COVID-19 patients.

BACKGROUND: The emergence of coronavirus disease 2019 (COVID-19) as a global health emergency necessitates continued investigation of the disease progression. This study investigated the relationship between eosinophilia and the severity of COVID-19 in chronic obstructive pulmonary disease (COPD) patients. METHODS: This cross-sectional study was conducted on 73 COPD patients infected by COVID-19 in Afzalipour Hospital, Iran. Peripheral blood samples were collected for hematological parameter testing, including eosinophil percentage, using Giemsa staining. Eosinophilia was defined as≥ 2% and non-eosinophilia as< 2%. The severity of pulmonary involvement was determined based on chest CT severity score (CT-SS) (based on the degree of involvement of the lung lobes, 0%: 0 points, 1-25%: 1 point, 26-50%: 2 points, 51-75%: 3 points, and 76-100%: 4 points). The CT-SS was the sum of the scores of the five lobes (range 0-20). RESULTS: The average age of patients was 67.90±13.71 years, and most were male (54.8%). Non-eosinophilic COPD patients were associated with more severe COVID-19 (P= 0.01) and lower oxygen saturation (P= 0.001). In addition, the study revealed a significant difference in the chest CT severity score (CT-SS) between non-eosinophilic (9.76±0.7) and eosinophilic COPD patients (6.26±0.63) (P< 0.001). Although non-eosinophilic COPD patients had a higher mortality rate, this difference was not statistically significant (P= 0.16). CONCLUSIONS: Our study demonstrated that reduced peripheral blood eosinophil levels in COPD patients with COVID-19 correlate with unfavorable outcomes. Understanding this association can help us identify high-risk COPD patients and take appropriate management strategies to improve their prognosis.

Associations between eosinophils and cancer risk in the UK Biobank.

Eosinophils exhibit anti-tumor cytotoxic responses in the tumor microenvironment and may contribute to tumor immunosurveillance. To assess the relationship between circulating eosinophils and cancer risk, we analyzed data from 443,542 adults aged 38-73 in the UK Biobank, who were initially cancer-free, had over a year of follow-up, and baseline white blood cell count measurements. Using multivariable Cox regression, we estimated hazard ratios (aHR) and 95% confidence intervals (95%CI) for each quartile increase in absolute eosinophil count (AEC) across 58 cancer types, adjusting for relevant confounders. During a median follow-up of 5.8 years, 22,747 incident cancer cases were diagnosed. We observed an inverse association, which met Bonferroni significance, between AEC and overall cancer risk (aHR, 95%CI 0.97, 0.95-0.98). Notably, 16 cancer types showed borderline associations (p <.05) with AEC, with 12 types displaying an inverse relationship. These included four hematologic cancers (acute and other myeloid leukemia, other lymphocytic leukemia, and chronic lymphocytic leukemia/small lymphocytic lymphoma; aHR range; 0.58-0.87) and eight nonhematologic cancers (melanoma and nose/middle ear, soft tissue/heart, gum/other mouth, tongue, lung, colon, and breast cancers; aHR range: 0.65-0.95). Higher AEC showed a borderline significant association with increased risk for intrahepatic bile duct cancer, Hodgkin lymphoma, diffuse large B-cell lymphoma, and chronic myeloid leukemia (aHR range: 1.13-1.42). Our study, the largest to date, provides insights into the relationship between blood eosinophils and a comprehensive list of incident cancers. The inverse association between AEC and overall cancer risk suggests a protective role for eosinophils in tumor surveillance.

Treating moderate-to-severe atopic dermatitis with benralizumab: results from the HILLIER study, a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: Atopic dermatitis (AD) is a chronic (long-lasting) skin disease that leads to dry, itchy, and swollen red spots, which can also be painful and flare up at any time. Some people with AD have a high number of eosinophils, a type of white blood cell, which are associated with worse disease. Medicated creams and lotions, prescribed by health care providers, are meant to reduce the symptoms of AD. For some people, these creams and lotions do not work. Benralizumab injection is a medication that reduces and removes eosinophils. A clinical trial called HILLER tested benralizumab to see if there was a difference in symptoms of AD after reducing or removing eosinophils. This article explains how benralizumab reduced eosinophils and the effect it had on AD symptoms in the HILLIER study. WHAT WERE THE MAIN CONCLUSIONS REPORTED BY THE RESEARCHERS?: Benralizumab reduced blood eosinophil numbers. However, benralizumab showed no evidence of treatment benefit on signs, symptoms, or severity of AD, as measured by three skin assessments compared with placebo. Benralizumab was well tolerated and had a safety profile that was consistent with previous studies. The five most commonly reported side effects were COVID-19 infection, upper respiratory tract infection, headache, swelling of the lymph nodes, and pink eye (conjunctivitis) in patients who received either benralizumab or placebo. WHAT ARE THE KEY TAKEAWAYS?: Benralizumab lowered the number of blood eosinophils without improving AD symptoms and was well tolerated.

Eosinophil biology from the standpoint of metabolism: implications for metabolic disorders and asthma.

Eosinophils, recognized for their immune and remodeling functions and participation in allergic inflammation, have recently garnered attention due to their impact on host metabolism, especially in the regulation of adipose tissue. Eosinophils are now known for their role in adipocyte beiging, adipokine secretion, and adipose tissue inflammation. This intricate interaction involves complex immune and metabolic processes, carrying significant implications for systemic metabolic health. Importantly, the interplay between eosinophils and adipocytes is bidirectional, revealing the dynamic nature of the immune-metabolic axis in adipose tissue. While the homeostatic regulatory role of eosinophils in the adipose tissue is appreciated, this relationship in the context of obesity or allergic inflammation is much less understood. Mechanistic details of eosinophil-adipose interactions, especially the direct regulation of adipocytes by eosinophils, are also lacking. Another poorly understood aspect is the metabolism of the eosinophils themselves, encompassing metabolic shifts during eosinophil subset transitions in different tissue microenvironments, along with potential effects of host metabolism on the programming of eosinophil hematopoiesis and the resulting plasticity. This review consolidates recent research in this emerging and fascinating frontier of eosinophil investigation, identifying unexplored areas and presenting innovative perspectives on eosinophil biology in the context of metabolic disorders and associated health conditions, including asthma.

Pharmacokinetics/pharmacodynamics of benralizumab in chronic rhinosinusitis with nasal polyps: Phase III, randomized, placebo-controlled OSTRO trial.

AIMS: Benralizumab, a humanized, afucosylated monoclonal antibody against the interleukin 5 receptor, α subunit, causes rapid depletion of eosinophils by antibody-dependent cellular cytotoxicity. We investigated the pharmacokinetic and pharmacodynamic effects of benralizumab in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) from the phase III OSTRO trial. METHODS: Patients received a placebo or 30 mg of benralizumab by subcutaneous injection every 8 weeks (first three doses every 4 weeks) to week 48; a subset of patients continued in an extended follow-up period to assess treatment durability to week 80. Serum benralizumab concentrations and blood eosinophil and basophil counts were assessed to week 80. Biomarker assessments were performed on nasal polyp tissue biopsies at week 56 and nasal lining fluid at weeks 24 and 56 to examine changes in immune cells and inflammatory mediators. RESULTS: Among 185 patients in this analysis, 93 received benralizumab. Serum benralizumab concentrations reached a steady state by week 24 (median concentration 385.52 ng mL-1); blood eosinophils were almost fully depleted and blood basophils were reduced between weeks 16 and 56. Nasal polyp tissue eosinophils decreased with benralizumab from 57.6 cells mm-2 at baseline to 0 cells mm-2 at week 56 (P < .001 vs placebo), and tissue mast cells were numerically reduced. In nasal lining fluid, eosinophil-derived neurotoxin was significantly reduced at weeks 24 and 56 (P < .001) and interleukin-17 at week 56 (P < .05) with benralizumab. CONCLUSION: Benralizumab treatment led to rapid, sustained, nearly complete depletion of eosinophils from blood and nasal polyp tissue in patients with CRSwNP.

[Burden and management of severe asthma in Russia: results from international observational study].

AIM: To assess clinical and demographic characteristics of severe asthma (SA) patients and their management in Russian Federation. MATERIALS AND METHODS: This publication provides data for Russian part of population of the international observational study. In Phase I, retrospective analysis of medical records of patients with SA was performed with assessment of clinical and demographic data, medical history, comorbidities, treatment approaches and healthcare utilization. Phase II was a cross-sectional collection of patient-reported outcomes: level of asthma control assessed by ACT (Asthma Control Test) and health-related quality of life (HRQoL) measured using the EQ-5D-5L questionnaire. Phase I patients were enrolled into Phase II if they signed a written consent form. RESULTS: A total of 315 patients were included in Phase I of the study, 106 (33.6%) of them entered Phase II. Majority of study participants were either obese (n=103; 39.8%) or overweight (n=94; 36.3%). The most common comorbidities were cardiovascular diseases (n=217; 71.4%), followed by chronic respiratory diseases (n=198; 68.8%). There were 268 (85.1%) patients who had at least one exacerbation during last 12 months. Data for blood eosinophil count were available in 176 patients; 81.3% of them (n=143) had only one test in the last 12 months. The mean (SD) last available blood eosinophil count was 161.2 (181.2) cells/mm3. Serum Immunoglobulin E (IgE) value was known for 88 patients, and the mean (SD) last measured IgE value was 254.3 (249.7) ng/mL. Only 4.7% of Phase II participants had ACT scores indicative of controlled asthma (>20). As much as 74.5% had scores ≤15 suggesting uncontrolled disease. Most patients also had impaired HRQoL. CONCLUSION: Most SA patients had poor disease control with frequent exacerbations and high number of comorbidities. Blood eosinophils and IgE level measurements were not evaluated routinely which might be a barrier for appropriate phenotyping and treatment selection.

Meta-analysis of peripheral blood eosinophils in clinical testing of chronic obstructive pulmonary disease patients.

Introduction: Meta-analysis was used to investigate the relationship between peripheral blood eosinophil (EOS) levels, clinical characteristics, and prognosis in chronic obstructive pulmonary disease (COPD)patients in previous literature. Aim: To analyse the correlation between peripheral blood EOS levels and clinical characteristics and prognosis of patients with COPD using meta-analysis. Material and methods: In databases such as PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wan Fang Data, literature related to the clinical characteristics or prognosis of COPD patients with high-level EOS published before July 2023 was searched for meta-analysis. Results: Through computer search and screening, 29 articles were ultimately included. The meta-analysis results showed that compared to conventional EOS levels, COPD patients with high EOS levels had a lower proportion of GOLD III-IV grade patients (OR = 00.78, 95% CI (0.68, 0.88), p < 0.001), lower CAT scores (OR = -1.01, 95% CI (-1.75, -0.28), p = 0.007), shorter hospital stay (OR = -1.33, 95% CI (-1.52, -1.14), p < 0.001), and lower mortality rate (OR = 0.53, 95% CI (0.42, 0.66), p < 0.001). The readmission rate was low (OR = 0.40, 95% CI (0.33, 0.48), p < 0.001), and there was no statistically significant difference in FEV1%pred (OR = -0.55, 95% CI (-1.33, 0.23), p = 0.17), higher FEV1/FVC values (OR = -0.45, 95% CI (-1.08, 0.18), p = 0.160), and mechanical ventilation usage rate (OR = 0.89, 95% CI (0.65, 1.21), p = 0.450) among COPD patients with different EOS levels. Conclusions: The levels of peripheral blood EOS in COPD patients are related to lung function, respiratory symptoms, etc.; Moreover, COPD patients with high-level EOS have shorter hospital stays, lower mortality and readmission rates. Therefore, ESO can be used as an auxiliary indicator for clinical symptom diagnosis of COPD patients and as an auxiliary indicator for predicting prognosis.

Kimura's Disease in Unusual Anatomical Locations: Clinical and Radiological Characteristics.

Purpose: To explore the clinical and imaging features of rare site Kimura's disease (KD). Methods: Retrospective analysis was conducted on the clinical manifestations, laboratory examinations, and imaging features of five patients with rare site KD. All imaging data, including the location, quantity, size, uniformity, boundary, and enhanced appearance of the lesion were evaluated by two independent radiologists. Results: Of the five patients, four were asymptomatic, and one experienced localized skin itching. Four cases involved subcutaneous nodules in the upper arm, while one was in the inguinal region. The main manifestations were single (three cases) or multiple (two cases) subcutaneous nodules/masses, with three patients accompanied by local lymph node enlargement. Four patients exhibited elevated eosinophil counts in their peripheral blood. Four patients had lesions with vascular flow voids; in three of these, the lesions also showed prominent enhancement. Notably, the lesion in a 5-year-old did not show vascular flow voids but displayed significant enhancement. Additionally, two patients showed edema around the lesions. Conclusion: The presence of solitary or multiple subcutaneous nodules/masses in the upper arm or inguinal area, accompanied by lymph node enlargement, elevated eosinophils in the peripheral blood, and the observation of internal vascular within the lesion, can aid in the diagnosis of KD occurring in uncommon anatomical locations.

Eosinophilic granulocytes as a potential prognostic marker for cancer progression and therapeutic response in malignant melanoma.

The importance of eosinophilic granulocytes in cancer has been widely discussed in recent years. The current study reviews the evidence on the role of eosinophilic granulocytes in melanoma as a prognostic marker for cancer progression and the efficacy of treatment with modern immune checkpoint inhibitors. A total of 33 human clinical studies were included in the review, with heterogeneous data due to differences in patients populations, study design and inclusion of small study groups. However, 28 of the 33 studies suggested that eosinophilic granulocytes could be used as a prognostic biomarker for outcome and/or potential response to systemic treatment and/or occurrence of adverse events in melanoma patients. Nevertheless, the exact role of eosinophils remains to be elucidated. Further prospective, larger and better controlled studies are warranted to clarify the significance of eosinophilic granulocytes in patients with melanoma, in more details.

Prevalence and Magnitude of Olfactory Dysfunction in Allergic Rhinitis.

BACKGROUND: Although allergic rhinitis (AR) can negatively impact the ability to smell, the degree to which this occurs is not clear and prevalence estimates vary among studies. This study had 4 main objectives: (1) To estimate the prevalence and the degree of olfactory dysfunction in AR patients; (2) To compare olfactory perception between AR patients with different persistence and severity of symptoms and determine if olfactory testing may aid in differentiating among Allergic Rhinitis and its Impact on Asthma (ARIA) groups; (3) To determine whether allergic reactions to different allergens differentially impact olfactory function, and (4) Verify possible changes in the olfactory epithelium (OE) caused by AR. METHODS: One hundred thirty-three patients with AR and one hundred controls were tested. The main outcome was the score in University of Pennsylvania Smell Identification Test (UPSIT®). The OE was examined using immunofluorescence markers for neuronal activity, apoptosis, oxidative stress, signal transduction, eosinophils, and epithelial thickness. RESULTS: Prevalence of olfactory dysfunction in the AR patients was higher (AR: 42.9% vs controls: 9%, P < .001). No difference was found either between intermittent and persistent disease cases (P = .58) or between cases with mild and those with moderate/severe symptomatology (P = .33). Lower olfactory capacity was not associated with the reaction to more (P = .48) or diverse types of allergens (Ps > .05). Although not significant, patients with AR had a greater amount of eosinophilia and a lower amount of cAMP (cyclic adenosine monophosphate) in the OE. CONCLUSION: The study highlights a higher prevalence of olfactory dysfunction in AR patients compared to controls, but olfactory testing may not effectively differentiate AR severity or allergen sensitivities. Although trends suggest potential pathophysiological changes in the OE of AR patients, further research is needed to validate these findings.

Androgens Modulate the Immune Profile in a Mouse Model of Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is associated with a low-grade inflammation, but it is unknown how hyperandrogenism, the hallmark of PCOS, affects the immune system. Using a PCOS-like mouse model, it is demonstrated that hyperandrogenism affects immune cell populations in reproductive, metabolic, and immunological tissues differently in a site-specific manner. Co-treatment with an androgen receptor antagonist prevents most of these alterations, demonstrating that these effects are mediated through androgen receptor activation. Dihydrotestosterone (DHT)-exposed mice displayed a drastically reduced eosinophil population in the uterus and visceral adipose tissue (VAT). A higher frequency of natural killer (NK) cells and elevated levels of IFN-γ and TNF-α are seen in uteri of androgen-exposed mice, while NK cells in VAT and spleen displayed a higher expression level of CD69, a marker of activation or tissue residency. Distinct alterations of macrophages in the uterus, ovaries, and VAT are also found in DHT-exposed mice and can potentially be linked to PCOS-like traits of the model. Indeed, androgen-exposed mice are insulin-resistant, albeit unaltered fat mass. Collectively, it is demonstrated that hyperandrogenism causes tissue-specific alterations of immune cells in reproductive organs and VAT, which can have considerable implications on tissue function and contribute to the reduced fertility and metabolic comorbidities associated with PCOS.

Multiple instance learning for eosinophil quantification of sinonasal histopathology images: A hierarchical determination on whole slide images.

KEY POINTS: We proposed a hierarchical framework including an unsupervised candidate image selection and a weakly supervised patch image detection based on multiple instance learning (MIL) to effectively estimate eosinophil quantities in tissue samples from whole slide images. MIL is an innovative approach that can help deal with the variability in cell distribution detection and enable automated eosinophil quantification from sinonasal histopathological images with a high degree of accuracy. The study lays the foundation for further research and development in the field of automated histopathological image analysis, and validation on more extensive and diverse datasets will contribute to real-world application.

Monitoring COPD patients: systemic and bronchial eosinophilic inflammation in a 2-year follow-up.

BACKGROUND: High blood eosinophils seem to predict exacerbations and response to inhaled corticosteroids (ICS) treatment in patients with chronic obstructive pulmonary disease (COPD). The aim of our study was to prospectively evaluate for 2 years, blood and sputum eosinophils in COPD patients treated with bronchodilators only at recruitment. METHODS: COPD patients in stable condition treated with bronchodilators only underwent monitoring of lung function, blood and sputum eosinophils, exacerbations and comorbidities every 6 months for 2 years. ICS was added during follow-up when symptoms worsened. RESULTS: 63 COPD patients were enrolled: 53 were followed for 1 year, 41 for 2 years, 10 dropped-out. After 2 years, ICS was added in 12/41 patients (29%) without any statistically significant difference at time points considered. Blood and sputum eosinophils did not change during follow-up. Only FEV1/FVC at T0 was predictive of ICS addition during the 2 year-follow-up (OR:0.91; 95% CI: 0.83-0.99, p = 0.03). ICS addition did not impact on delta (T24-T0) FEV1, blood and sputum eosinophils and exacerbations. After 2 years, patients who received ICS had higher blood eosinophils than those in bronchodilator therapy (p = 0.042). Patients with history of ischemic heart disease increased blood eosinophils after 2 years [p = 0.03 for both percentage and counts]. CONCLUSIONS: Blood and sputum eosinophils remained stable during the 2 year follow-up and were not associated with worsened symptoms or exacerbations. Almost 30% of mild/moderate COPD patients in bronchodilator therapy at enrollment, received ICS for worsened symptoms in a 2 year-follow-up and only FEV1/FVC at T0 seems to predict this addition. History of ischemic heart disease seems to be associated with a progressive increase of blood eosinophils.

The Role of Galectins in Asthma Pathophysiology: A Comprehensive Review.

Galectins are a group of ß-galactoside-binding proteins with several roles in immune response, cellular adhesion, and inflammation development. Current evidence suggest that these proteins could play a crucial role in many respiratory diseases such as pulmonary fibrosis, lung cancer, and respiratory infections. From this standpoint, an increasing body of evidence have recognized galectins as potential biomarkers involved in several aspects of asthma pathophysiology. Among them, galectin-3 (Gal-3), galectin-9 (Gal-9), and galectin-10 (Gal-10) are the most extensively studied in human and animal asthma models. These galectins can affect T helper 2 (Th2) and non-Th2 inflammation, mucus production, airway responsiveness, and bronchial remodeling. Nevertheless, while higher Gal-3 and Gal-9 concentrations are associated with a stronger degree of Th-2 phlogosis, Gal-10, which forms Charcot-Leyden Crystals (CLCs), correlates with sputum eosinophilic count, interleukin-5 (IL-5) production, and immunoglobulin E (IgE) secretion. Finally, several galectins have shown potential in clinical response monitoring after inhaled corticosteroids (ICS) and biologic therapies, confirming their potential role as reliable biomarkers in patients with asthma.

scRNA-seq profiling of human granulocytes reveals expansion of developmentally flexible neutrophil precursors with mixed neutrophil and eosinophil properties in asthma.

Neutrophils and eosinophils share common hematopoietic precursors and usually diverge into distinct lineages with unique markers before being released from their hematopoietic site, which is the bone marrow (BM). However, previous studies identified an immature Ly6g(+) Il-5Rα(+) neutrophil population in mouse BM, expressing both neutrophil and eosinophil markers suggesting hematopoietic flexibility. Moreover, others have reported neutrophil populations expressing eosinophil-specific cell surface markers in tissues and altered disease states, confusing the field regarding eosinophil origins, function, and classification. Despite these reports, it is still unclear whether hematopoietic flexibility exists in human granulocytes. To answer this, we utilized single-cell RNA sequencing (scRNA-seq) and CITE-seq to profile human BM and circulating neutrophils and eosinophils at different stages of differentiation and determine whether neutrophil plasticity plays role in asthmatic inflammation. We show that immature metamyelocyte neutrophils in humans expand during severe asthmatic inflammation and express both neutrophil and eosinophil markers. We also show an increase in tri-lobed eosinophils with mixed neutrophil and eosinophil markers in allergic asthma and that IL-5 promotes differentiation of immature blood neutrophils into tri-lobed eosinophilic phenotypes suggesting a mechanism of emergency granulopoiesis to promote myeloid inflammatory or remodeling response in patients with chronic asthma. By providing insights into unexpectedly flexible granulocyte biology and demonstrating emergency hematopoiesis in asthma, our results highlight the importance of granulocyte plasticity in eosinophil development and allergic diseases.

Pre-asthma: a useful concept? A EUFOREA paper. Part 2-late onset eosinophilic asthma.

The concept of pre-diabetes has led to provision of measures to reduce disease progression through identification of subjects at risk of diabetes. We previously considered the idea of pre-asthma in relation to allergic asthma and considered that, in addition to the need to improve population health via multiple measures, including reduction of exposure to allergens and pollutants and avoidance of obesity, there are several possible specific means to reduce asthma development in those most at risk (pre- asthma). The most obvious is allergen immunotherapy (AIT), which when given for allergic rhinitis (AR) has reasonable evidence to support asthma prevention in children (2) but also needs further study as primary prevention. In this second paper we explore the possibilities for similar actions in late onset eosinophilic asthma.

Considerations on the Evolutionary Biology and Functions of Eosinophils: What the 'Haeckel'?

The origins and evolution of the eosinophilic leukocyte has received only scattered attention since Paul Ehrlich first named this granulocyte. Studies suggest that myeloperoxidase, expressed by granulocytes, and eosinophil peroxidase diverged some 60-70 million years ago, but invertebrate to vertebrate evolution of the eosinophil lineage is unknown. Vertebrate eosinophils have been characterized extensively in representative species at light microscopic, ultrastructural, genetic, and biochemical levels. Understanding of eosinophil function continues to expand and includes to date regulation of "Local Immunity And/Or Remodeling/Repair" (the so-called LIAR hypothesis), modulation of innate and adaptive immune responses, maintenance of tissue and metabolic homeostasis, and under pathologic conditions, inducers of tissue damage, repair, remodeling, and fibrosis. This contrasts with their classically considered primary roles in host defense against parasites and other pathogens, and involvement in T-helper 2 inflammatory and immune responses. The eosinophils' early appearance during evolution and continued retention within the innate immune system across taxa illustrate their importance during evolutionary biology. However, successful pregnancies in eosinophil-depleted humans/primates treated with biologics, host immune responses to parasites in eosinophil-deficient mice, and the absence of significant developmental or functional abnormalities in eosinophil-deficient mouse strains under laboratory conditions, raise questions of the continuing selective advantages of the eosinophil lineage in mammals and humans. The objectives of this review are to provide an overview on evolutionary origins of eosinophils across the animal kingdom, discuss some of their main functions in the context of potential evolutionary relevance, and highlight the need for further research on eosinophil functions and functional evolution.