Comparison of pancreatic enzyme abnormalities and protease-activated receptor-2-positive eosinophils in the duodenum of patients with functional dyspepsia-irritable bowel syndrome overlap with functional dyspepsia alone in Asian populations

BACKGROUND AND AIM

Some patients with functional gastrointestinal disorders exhibit pancreatic dysfunctions and pancreatic enzyme abnormalities. Thus, we aimed to clarify whether significant differences in clinical characteristics, prevalence of pancreatic enzyme abnormalities, duodenal inflammation, and protease-activated receptor 2 (PAR2) expression levels related to hypersensitivity exist between functional dyspepsia (FD) alone and FD-irritable bowel syndrome (IBS) overlap group.

METHODS

Ninety-three patients based on the Rome IV criteria, FD alone (n = 44) and FD overlapped with IBS (n = 49) group were enrolled. The patients scored their own clinical symptoms after consuming high-fat meals. Serum trypsin, PLA2, lipase, p-amylase, and elastase-1 levels were measured. PAR2, eotaxin-3, and TRPV4 mRNA levels in duodenum were determined using real-time polymerase chain reaction methods. PRG2- and PAR2 in the duodenum were evaluated using immunostaining.

RESULTS

FD score and global GSRS in patients with FD-IBS overlap were significantly higher than FD alone. Although the prevalence of pancreatic enzyme abnormalities in patients with FD alone was significantly (P < 0.01) higher than that in FD-IBS overlap, the ratio of aggravation of clinical symptoms following high-fat intake in patients with FD-IBS overlap was significantly higher (P = 0.007) than that in patients with FD alone. PAR2- and PRG2-double positive cells were localized in the degranulated eosinophils in the duodenum of patients with FD-IBS overlap. The number of PAR2- and PRG2-double positive cells in FD-IBS overlap was significantly (P < 0.01) higher than FD alone.

CONCLUSIONS

Pancreatic enzyme abnormalities and PAR2 expression on degranulated eosinophils infiltrations in the duodenum may be associated with the pathophysiology of patients with FD-IBS overlap in Asian populations.

Eosinophilia in cancer and its regulation by sex hormones

Gender differences in the functionality of the immune system have been attributed, in part, to direct and indirect effects of sex steroids, especially estrogens, on immune cell repertoire and activity. Notable are studies that have defined roles for estrogens in the regulation of the biology of dendritic cells (DCs), macrophages, T cells and natural killer (NK) cells. Although estrogens can modulate eosinophil function, the mechanisms by which this occurs and how it contributes to the pathobiology of different diseases remains underexplored. Furthermore, although the importance of eosinophils in infection is well established, it remains unclear as to how these innate immune cells, which are present in different tumors, impact the biology of cancer cells and/or response to therapeutics. The observation that eosinophilia influences the efficacy of immune checkpoint blockers (ICBs) is significant considering the role of estrogens as regulators of eosinophil function and recent studies suggesting that response to ICBs is impacted by gender. Thus, in this review, we consider what is known about the roles of estrogen(s) in regulating tissue eosinophilia/eosinophil function and how this influences the pathobiology of breast cancer (in particular). This information provides the context for a discussion of how estrogens/the estrogen receptor (ER) signaling axis can be targeted in eosinophils and how this would be expected to influence the activity of standard-of-care interventions and contemporary immunotherapy regimens in cancer(s).

Differential role of mucus plugs in asthma: Effects of smoking and association with airway inflammation

BACKGROUND

The physiological importance of mucus plugs in computed tomography (CT) imaging is being increasingly recognized. However, whether airway inflammation and smoking affect the association between mucus plugs and clinical-physiological outcomes in asthma remains to be elucidated. The objective of this study is to examine how airway inflammation and/or smoking affect the correlation of CT-based mucus plug scores with exacerbation frequency and airflow limitation indices in asthma.

METHODS

A total of 168 patients with asthma who underwent chest CT and sputum evaluation were enrolled and classified in eosinophilic asthma (EA; n = 103) and non-eosinophilic asthma (NEA; n = 65) groups based on sputum eosinophil percentage (cut-off: 3%). The mucus plug score was defined as the number of lung segments with mucus plugs seen on CT.

RESULTS

More mucus plugs were detected on CT scans in the EA group than in the NEA group, regardless of smoking status. Mucus plug score and exacerbation frequency during one year after enrollment were significantly associated in the EA group but not in the NEA group after adjusting for demographics, blood eosinophil count, and fractional exhaled nitric oxide. Mucus plug score was associated with percentage of predicted forced expiratory volume in 1 s in non-smoking individuals in the EA and NEA group and in smoking individuals in the EA group but not in the NEA group after adjusting for demographics.

CONCLUSIONS

The association of mucus plug score with exacerbation frequency and reduced lung function may vary due to airway inflammatory profile and smoking status in asthma.

Solving the Conundrum of Eosinophils in Alloimmunity

Eosinophils are bone-marrow-derived granulocytes known for their ability to facilitate clearance of parasitic infections and their association with asthma and other inflammatory diseases. The purpose of this review is to discuss the currently available human observational and animal experimental data linking eosinophils to the immunologic response in solid organ transplantation. First, we present observational human studies that demonstrate a link between transplantation and eosinophils yet were unable to define the exact role of this cell population. Next, we describe published experimental models and demonstrate a defined mechanistic role of eosinophils in downregulating the alloimmune response to murine lung transplants. The overall summary of this data suggests that further studies are needed to define the role of eosinophils in multiple solid organ allografts and points to the possibility of manipulating this cell population to improve graft survival.

Eosinophils mediate SIgA production triggered by TLR2 and TLR4 to control Ascaris suum infection in mice

Human ascariasis is the most prevalent but neglected tropical disease in the world, affecting approximately 450 million people. The initial phase of Ascaris infection is marked by larval migration from the host's organs, causing mechanical injuries followed by an intense local inflammatory response, which is characterized mainly by neutrophil and eosinophil infiltration, especially in the lungs. During the pulmonary phase, the lesions induced by larval migration and excessive immune responses contribute to tissue remodeling marked by fibrosis and lung dysfunction. In this study, we investigated the relationship between SIgA levels and eosinophils. We found that TLR2 and TLR4 signaling induces eosinophils and promotes SIgA production during Ascaris suum infection. Therefore, control of parasite burden during the pulmonary phase of ascariasis involves eosinophil influx and subsequent promotion of SIgA levels. In addition, we also demonstrate that eosinophils also participate in the process of tissue remodeling after lung injury caused by larval migration, contributing to pulmonary fibrosis and dysfunction in re-infected mice. In conclusion, we postulate that eosinophils play a central role in mediating host innate and humoral immune responses by controlling parasite burden, tissue inflammation, and remodeling during Ascaris suum infection. Furthermore, we suggest that the use of probiotics can induce eosinophilia and SIgA production and contribute to controlling parasite burden and morbidity of helminthic diseases with pulmonary cycles.

Role of Eosinophils in Intestinal Inflammation and Fibrosis in Inflammatory Bowel Disease: An Overlooked Villain?

Eosinophils are leukocytes which reside in the gastrointestinal tract under homeostatic conditions, except for the esophagus which is normally devoid of eosinophils. Research on eosinophils has primarily focused on anti-helminth responses and type 2 immune disorders. In contrast, the search for a role of eosinophils in chronic intestinal inflammation and fibrosis has been limited. With a shift in research focus from adaptive to innate immunity and the fact that the eosinophilic granules are filled with inflammatory mediators, eosinophils are becoming a point of interest in inflammatory bowel diseases. In the current review we summarize eosinophil characteristics and recruitment as well as the current knowledge on presence, inflammatory and pro-fibrotic functions of eosinophils in inflammatory bowel disease and other chronic inflammatory conditions, and we identify research gaps which should be covered in the future.

Eosinophils are part of the granulocyte response in tuberculosis and promote host resistance in mice

Host resistance to Mycobacterium tuberculosis (Mtb) infection requires the activities of multiple leukocyte subsets, yet the roles of the different innate effector cells during tuberculosis are incompletely understood. Here we uncover an unexpected association between eosinophils and Mtb infection. In humans, eosinophils are decreased in the blood but enriched in resected human tuberculosis lung lesions and autopsy granulomas. An influx of eosinophils is also evident in infected zebrafish, mice, and nonhuman primate granulomas, where they are functionally activated and degranulate. Importantly, using complementary genetic models of eosinophil deficiency, we demonstrate that in mice, eosinophils are required for optimal pulmonary bacterial control and host survival after Mtb infection. Collectively, our findings uncover an unexpected recruitment of eosinophils to the infected lung tissue and a protective role for these cells in the control of Mtb infection in mice.

Ding Chuan Tang Attenuates Airway Inflammation and Eosinophil Infiltration in Ovalbumin-Sensitized Asthmatic Mice

Asthma is a T helper 2 (Th2) cell-associated chronic inflammatory diseases characterized with airway obstruction, increased mucus production, and eosinophil infiltration. Conventional medications for asthma treatment cannot fully control the symptoms, and potential side effects are also the concerns. Thus, complement or alternative medicine (CAM) became a new option for asthma management. Ding Chuan Tang (DCT) is a traditional Chinese herbal decoction applied mainly for patients with coughing, wheezing, chest tightness, and asthma. Previously, DCT has been proved to improve children airway hyperresponsiveness (AHR) in a randomized and double-blind clinical trial. However, the mechanisms of how DCT alleviates AHR remain unclear. Since asthmatic features such as eosinophil infiltration, IgE production, and mucus accumulation are relative with Th2 responses, we hypothesized that DCT may attenuate asthma symptoms through regulating Th2 cells. Ovalbumin (OVA) was used as a stimulant to sensitize BALB/c mice to establish an asthmatic model. AHR was detected one day before sacrifice. BALF and serum were collected for immune cell counting and antibody analysis. Splenocytes were cultured with OVA in order to determine Th2 cytokine production. Lung tissues were collected for histological and gene expression analyses. Our data reveal that DCT can attenuate AHR and eosinophil accumulation in the 30-day sensitization asthmatic model. Histological results demonstrated that DCT can reduce cell infiltration and mucus production in peribronchial and perivascular site. In OVA-stimulated splenocyte cultures, a significant reduction of IL-5 and IL-13 in DCT-treated mice suggests that DCT may alleviate Th2 responses. In conclusion, the current study demonstrates that DCT has the potential to suppress allergic responses through the reduction of mucus production, eosinophil infiltration, and Th2 activity in asthma.

Detrimental role of IL-33/ST2 pathway sustaining a chronic eosinophil-dependent Th2 inflammatory response, tissue damage and parasite burden during Toxocara canis infection in mice

Toxocariasis is a neglected disease that affects people around the world. Humans become infected by accidental ingestion of eggs containing Toxocara canis infective larvae, which upon reaching the intestine, hatch, penetrate the mucosa and migrate to various tissues such as liver, lungs and brain. Studies have indicated that Th2 response is the main immune defense mechanism against toxocariasis, however, there are still few studies related to this response, mainly the IL-33/ST2 pathway. Some studies have reported an increase in IL-33 during helminth infections, including T. canis. By binding to its ST2 receptor, IL-33 stimulating the Th2 polarized immune cell and cytokine responses. Thus, we aimed to investigate the role of the IL-33/ST2 pathway in the context of T. canis larval migration and the immunological and pathophysiological aspects of the infection in the liver, lungs and brain from Wild-Type (WT) BALB/c background and genetically deficient mice for the ST2 receptor (ST2^-/-). The most important findings revealed that the IL-33/ST2 pathway is involved in eosinophilia, hepatic and cerebral parasitic burden, and induces the formation of granulomas related to tissue damage and pulmonary dysfunction. However, ST2^-/- mice, the immune response was skewed to Th1/Th17 type than Th2, that enhanced the control of parasite burden related to IgG2a levels, tissue macrophages infiltration and reduced lung dysfunction. Collectively, our results demonstrate that the Th2 immune response triggered by IL-33/ST2 pathway mediates susceptibility to T. canis, related to parasitic burden, eosinophilia and granuloma formation in which consequently contributes to tissue inflammation and injury.

Toxocariasis is a neglected disease caused by Toxocara canis, which has 19% worldwide seroprevalence, and is associated with socioeconomic, geographic and environmental factors. Humans become infected by accidental ingestion of T. canis eggs present in contaminated food, water or soil. After ingestion, the larvae hatch in the intestine and can reach various tissues such as liver, lung and brain. Helminth infections usually trigger a Th2 immune response in the host, by releasing cytokines such as IL-4, IL-5, IL-13 and IL-33. IL-33 is an alarmin that binds to the ST2 receptor, and some studies have observed an increase in this cytokine in toxocariasis, however there are no studies regarding the IL-33/ST2 role in this infection. Thus, we evaluated the influence of this pathway by analyzing immunological and pathophysiological aspects in T. canis-infected mice. Our results demonstrated that the IL-33/ST2 pathway is related to parasite burden on the liver and brain and also increases the number of eosinophils in the blood and tissues. In addition, it involved with the pulmonary immune response and granulomas with impact in lung function. In conclusion, the IL-33/ST2 pathway governs the host susceptibility to T. canis in mice.

The JAK1/2 inhibitor baricitinib suppresses eosinophil effector function and restricts allergen-induced airway eosinophilia

BACKGROUND

Eosinophilic asthma is increasingly recognized as one of the most severe and difficult-to-treat asthma subtypes. The JAK/STAT pathway is the principal signaling mechanism for a variety of cytokines and growth factors involved in asthma. However, the direct effect of JAK inhibitors on eosinophil effector function has not been addressed thus far.

OBJECTIVE

Here we compared the effects of the JAK1/2 inhibitor baricitinib and the JAK3 inhibitor tofacitinib on eosinophil effector function in vitro and in vivo.

METHODS

Differentiation of murine bone marrow-derived eosinophils. Migratory responsiveness, respiratory burst, phagocytosis and apoptosis of human peripheral blood eosinophils were assessed in vitro. In vivo effects were investigated in a mouse model of acute house dust mite-induced airway inflammation in BALB/c mice.

RESULTS

Baricitinib more potently induced apoptosis and inhibited eosinophil chemotaxis and respiratory burst, while baricitinib and tofacitinib similarly affected eosinophil differentiation and phagocytosis. Of the JAK inhibitors, oral application of baricitinib more potently prevented lung eosinophilia in mice following allergen challenge. However, both JAK inhibitors neither affected airway resistance nor compliance.

CONCLUSION

Our data suggest that the JAK1/2 inhibitor baricitinib is even more potent than the JAK3 inhibitor tofacitinib in suppressing eosinophil effector function. Thus, targeting the JAK1/2 pathway represents a promising therapeutic strategy for eosinophilic inflammation as observed in severe eosinophilic asthma.

Dynamic Decrease in Eosinophil After Intravenous Thrombolysis Predicts Poor Prognosis of Acute Ischemic Stroke: A Longitudinal Study

Background and Purpose

Blood eosinophil counts are thought to be associated with atherosclerosis in acute ischemic stroke (AIS) and AIS severity. We aimed to investigate 1): the temporal profile of eosinophil in AIS patients treated with recombinant tissue plasminogen activator (r-tPA); 2): The association between dynamic eosinophil and 3-month outcomes in different AIS etiologies; 3): incremental predictive ability of dynamic eosinophil adding to conventional model; and 4): the longitudinal change of neutrophil-to-lymphocyte ratio (NLR) and compared its prognostic value with eosinophils.

Methods

A total of 623 AIS patients with intravenous thrombolysis in two hospitals were included. Blood samples were obtained on admission, within 24 h after an intravenous thrombolysis and on the seventh day. A multivariate logistic regression model with restricted cubic spline was performed to explore the association between dynamic eosinophil and a 3-month poor outcome. C-statistic, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were adopted to explore the incremental predictive ability.

Results

Percent change in eosinophil counts after intravenous thrombolysis was median -25.00% (IQR -68.25%-+14.29%). Decrease in eosinophil >75% after intravenous thrombolysis was associated with 2.585 times risk for poor outcome and 13.836 times risk for death. However, the association were weak for patients outside of cardioembolic stroke. Adding eosinophil changes to a conventional model improved the discriminatory ability of poor outcome (NRI = 53.3%; IDI = 2.2%) and death (NRI = 101.0%; IDI = 6.9%).

Conclusions

Dynamic decrease in eosinophil after intravenous thrombolysis predicts a 3-month poor outcome and death in AIS patients with r-tPA treatment and improved the predictive ability of conventional model. However, this result needs to be interpreted carefully in non-cardioembolic AIS patients.

Emerging Evidence for Pleiotropism of Eosinophils

Eosinophils are complex granulocytes with the capacity to react upon diverse stimuli due to their numerous and variable surface receptors, which allows them to respond in very different manners. Traditionally believed to be only part of parasitic and allergic/asthmatic immune responses, as scientific studies arise, the paradigm about these cells is continuously changing, adding layers of complexity to their roles in homeostasis and disease. Developing principally in the bone marrow by the action of IL-5 and granulocyte macrophage colony-stimulating factor GM-CSF, eosinophils migrate from the blood to very different organs, performing multiple functions in tissue homeostasis as in the gastrointestinal tract, thymus, uterus, mammary glands, liver, and skeletal muscle. In organs such as the lungs and gastrointestinal tract, eosinophils are able to act as immune regulatory cells and also to perform direct actions against parasites, and bacteria, where novel mechanisms of immune defense as extracellular DNA traps are key factors. Besides, eosinophils, are of importance in an effective response against viral pathogens by their nuclease enzymatic activity and have been lately described as involved in severe acute respiratory syndrome coronavirus SARS-CoV-2 immunity. The pleiotropic role of eosinophils is sustained because eosinophils can be also detrimental to human physiology, for example, in diseases like allergies, asthma, and eosinophilic esophagitis, where exosomes can be significant pathophysiologic units. These eosinophilic pathologies, require specific treatments by eosinophils control, such as new monoclonal antibodies like mepolizumab, reslizumab, and benralizumab. In this review, we describe the roles of eosinophils as effectors and regulatory cells and their involvement in pathological disorders and treatment.

Prognostic impact of eosinophils in peripheral blood and tumor site in patients with esophageal squamous cell carcinoma treated with concurrent chemoradiotherapy

To date, no effective biological markers have been identified for predicting the prognosis of esophageal cancer patients. Recent studies have shown that eosinophils are independent prognostic factors in some cancers. This study aimed to identify the prognostic impact of eosinophils in esophageal squamous cell carcinoma patients treated with concurrent chemoradiotherapy (CCRT).This study enrolled 136 patients who received CCRT for locally advanced unresectable esophageal squamous cell carcinoma (ESCC). We evaluated the survival time and clinical pathological characteristics of eosinophils. The Kaplan-Meier method was used to estimate survival data. The log-rank test was used for univariate analysis and the Cox proportional hazards regression model was used to conduct a multivariate analysis.Kaplan-Meier analysis revealed that high eosinophil infiltration correlated with better overall survival (OS) (P = .008) and better progression-free survival (PFS) (P = .015). The increase in absolute eosinophil count after CCRT also enhanced OS (P = .005) and PFS (P = .007). The PFS and OS in patients with high blood eosinophil count before CCRT (>2%) was better than those with low blood eosinophil count(<2%) (P = .006 and P = .001, respectively). Additionally, the multivariate analysis revealed that disease stage and high eosinophil infiltration, increased peripheral blood absolute eosinophil count after CCRT, and high peripheral blood eosinophil count before CCRT were independent prognostic indicators.High eosinophil count of tumor site, increased peripheral blood absolute eosinophil count after CCRT, and high peripheral blood eosinophil count before CCRT are favorable prognostic factors for patients with ESCC treated with CCRT.

Generation of Mouse Eosinophils in Tissue Culture from Unselected Bone Marrow Progenitors

Human eosinophilic leukocytes are found in peripheral blood and tissues at homeostasis and at elevated levels in atopic disorders. As inbred strains of mice (Mus musculus) are currently the models of choice for the study of disease mechanisms in vivo, a full understanding of mouse eosinophils is critical for interpretation of experimental findings. Toward this end, several years ago we presented a protocol for generating mouse eosinophils in tissue culture from unselected bone marrow progenitors (Dyer et al., J Immunol 181: 4004-4009, 2008). This method has been implemented widely and has proven to be effective for generating phenotypically normal eosinophils from numerous mouse strains and genotypes. Here we provide a detailed version of this protocol, along with suggestions and notes for its careful execution. We have also included several protocol variations and suggestions for improvements.

Eosinophils: Cells known for over 140 years with broad and new functions

Eosinophils are multifunctional leukocytes, being involved in the host defense against helminth infection, tissue homeostasis and repair of injured tissue. However, eosinophils also play critical roles in shaping the pathogenesis of allergic diseases, including fibrotic responses in allergic diseases. Eosinophils consist of various granules that are a source of cytokines, chemokines, enzymes, extracellular matrix and growth factors. Recent studies have revealed that eosinophil extracellular trap cell death (EETosis) exacerbates eosinophilic inflammation by releasing the products, including Charcot-Leyden crystals (CLCs). In type 2 inflammatory diseases, memory-type pathogenic helper T (Tpath) cells are involved in shaping the pathogenesis of eosinophilic inflammation by recruiting and activating eosinophils in vivo. We herein review the molecular mechanisms underlying the development of eosinophils and the various functions of granules, including CLCs, during eosinophilic inflammation. We also discuss the double-edged roles of eosinophils in tissue repair and type 2 immune inflammation.

How to detect eosinophil ETosis (EETosis) and extracellular traps

Eosinophils are short-lived and comprise only a small population of circulating leukocytes; however, they play surprisingly multifunctional roles in homeostasis and various diseases including allergy and infection. Recent research has shed light on active cytolytic eosinophil cell death that releases eosinophil extracellular traps (EETs) and total cellular contents, namely eosinophil extracellular trap cell death (EETosis). The pathological contribution of EETosis was made more cogent by recent findings that a classical pathological finding of eosinophilic inflammation, that of Charcot-Leyden crystals, is closely associated with EETosis. Currently no gold standard methods to identify EETosis exist, but “an active eosinophil lysis that releases cell-free granules and net-like chromatin structure” appears to be a common feature of EETosis. In this review, we describe several approaches that visualize EETs/EETosis in clinical samples and in vitro studies using isolated human eosinophils. EETs/EETosis can be observed using simple chemical or fluorescence staining, immunostaining, and electron microscopy, although it is noteworthy that visualization of EETs is greatly changed by sample preparation including the extracellular space of EETotic cells and shear flow. Considering the multiple aspects of biological significance, further study into EETs/EETosis is warranted to give a detailed understanding of the roles played in homeostasis and disease pathogenesis.

The multiple functions and subpopulations of eosinophils in tissues under steady-state and pathological conditions

Eosinophils not only play a critical role in the pathogenesis of eosinophil-associated diseases, but they also have multiple important biological functions, including the maintenance of homeostasis, host defense against infections, immune regulation through canonical Th1/Th2 balance modulation, and anti-inflammatory and anti-tumorigenic activities. Recent studies have elucidated some emerging roles of eosinophils in steady-state conditions; for example, eosinophils contribute to adipose tissue metabolism and metabolic health through alternatively activated macrophages and the maintenance of plasma cells in intestinal tissue and bone marrow. Moreover, eosinophils exert tissue damage through eosinophil-derived cytotoxic mediators that are involved in eosinophilic airway inflammation, leading to diseases including asthma and chronic rhinosinusitis with nasal polyps characterized by fibrin deposition through excessive response by eosinophils-induced. Thus, eosinophils possessing these various effects reflect the heterogenous features of these cells, which suggests the existence of distinct different subpopulations of eosinophils between steady-state and pathological conditions. Indeed, a recent study demonstrated that instead of dividing eosinophils by classical morphological changes into normodense and hypodense eosinophils, murine eosinophils from lung tissue can be phenotypically divided into two distinct subtypes: resident eosinophils and inducible eosinophils gated by Siglec-F^int CD62L⁺ CD101^low and Siglec-F^high CD62L^- CD101^high, respectively. However, it is difficult to explain every function of eosinophils by rEos and iEos, and the relationship between the functions and subpopulations of eosinophils remains controversial. Here, we overview the multiple roles of eosinophils in the tissue and their biological behavior in steady-state and pathological conditions. We also discuss eosinophil subpopulations.

Diabetes mellitus impairs circulating proangiogenic granulocytes

AIMS/HYPOTHESIS

Cardiovascular risk in diabetes is at least in part attributable to defective angiogenesis. Since diabetes negatively affects blood cells involved in angiogenesis, we herein evaluated whether diabetes impairs proangiogenic granulocytes (PAGs).

METHODS

We characterised and quantified PAGs as CD49d⁺ granulocytes in peripheral blood of participants with type 2 or type 1 diabetes and in non-diabetic control participants. We evaluated PAG antigenic profile and assessed in vitro functional properties of CD49d⁺ granulocytes using 2D and 3D angiogenesis assays. We also quantified PAGs before and after glucose control with a sodium-glucose cotransporter 2 (SGLT2) inhibitor, dapagliflozin. In parallel, we measured Ly6G⁺CD49d⁺ PAGs in streptozotocin-induced type 1-like diabetic mice vs non-diabetic control mice.

RESULTS

PAGs were composed of eosinophils (>80%) and neutrophils (<20%). Within both populations, CD49d identified CXCR4^high/VEGFR1^high cells. CD49d⁺ granulocytes supported in vitro angiogenesis by endothelial cells significantly more than CD49d^- control granulocytes, and physically interacted with endothelial cells. Granulocytes from type 2 diabetic participants had a profoundly impaired capacity to stimulate endothelial cell tubule formation compared with those from non-diabetic control participants. CD49d⁺ PAGs were reduced by 30-40% and were functionally impaired in diabetic vs control individuals. PAG levels inversely correlated with plasma glucose (r = -0.25; p = 0.025) and significantly increased 1.8-times after glucose control with dapagliflozin, which reduced HbA_1c by 1.0% (11 mmol/mol). Levels of Ly6G⁺CD49d⁺ PAGs were also significantly reduced also in type 1 diabetic mice vs control mice.

CONCLUSIONS/INTERPRETATION

We illustrate a significant impairment of PAGs in diabetes and provide evidence for a direct role of hyperglycaemia. These findings add mechanistic information to explain the defective angiogenesis in diabetes. Graphical abstract.

Eosinophils regulate adipose tissue inflammation and sustain physical and immunological fitness in old age

Adipose tissue eosinophils (ATEs) are important in the control of obesity-associated inflammation and metabolic disease. However, the way in which ageing impacts the regulatory role of ATEs remains unknown. Here, we show that ATEs undergo major age-related changes in distribution and function associated with impaired adipose tissue homeostasis and systemic low-grade inflammation in both humans and mice. We find that exposure to a young systemic environment partially restores ATE distribution in aged parabionts and reduces adipose tissue inflammation. Approaches to restore ATE distribution using adoptive transfer of eosinophils from young mice into aged recipients proved sufficient to dampen age-related local and systemic low-grade inflammation. Importantly, restoration of a youthful systemic milieu by means of eosinophil transfers resulted in systemic rejuvenation of the aged host, manifesting in improved physical and immune fitness that was partially mediated by eosinophil-derived IL-4. Together, these findings support a critical function of adipose tissue as a source of pro-ageing factors and uncover a new role of eosinophils in promoting healthy ageing by sustaining adipose tissue homeostasis.

IL-5 Exposure In Utero Increases Lung Nerve Density and Airway Reactivity in Adult Offspring

Asthma is characterized by airway hyperreactivity and inflammation. In the lungs, parasympathetic and sensory nerves control airway tone and induce bronchoconstriction. Dysregulation of these nerves results in airway hyperreactivity. Humans with eosinophilic asthma have significantly increased sensory nerve density in airway epithelium, suggesting that type 2 cytokines and inflammatory cells promote nerve growth. Similarly, mice with congenital airway eosinophilia also have airway hyperreactivity and increased airway sensory nerve density. Here, we tested whether this occurs during development. We show that transgenic mice that overexpress IL-5, a cytokine required for eosinophil hematopoiesis, give birth to wild-type offspring that have significantly increased airway epithelial nerve density and airway hyperreactivity that persists into adulthood. These effects are caused by in utero exposure to maternal IL-5 and resulting fetal eosinophilia. Allergen exposure of these adult wild-type offspring results in severe airway hyperreactivity, leading to fatal reflex bronchoconstriction. Our results demonstrate that fetal exposure to IL-5 is a developmental origin of airway hyperreactivity, mediated by hyperinnervation of airway epithelium.

Lysophosphatidylcholines inhibit human eosinophil activation and suppress eosinophil migration in vivo

Eosinophils are important multifaceted effector cells involved in allergic inflammation. Following allergen challenge, eosinophils and other immune cells release secreted phospholipases, generating lysophosphatidylcholines (LPCs). LPCs are potent lipid mediators, and serum levels of LPCs associate with asthma severity, suggesting a regulatory activity of LPCs in asthma development. As of yet, the direct effects of LPCs on eosinophils remain unclear. In the present study, we tested the effects of the major LPC species (16:0, 18:0 and 18:1) on eosinophils isolated from healthy human donors. Addition of saturated LPCs in the presence of albumin rapidly disrupted cholesterol-rich nanodomains on eosinophil cell membranes and suppressed multiple eosinophil effector responses, such as CD11b upregulation, degranulation, chemotaxis, and downstream signaling. Furthermore, we demonstrate in a mouse model of allergic cell recruitment, that LPC treatment markedly reduces immune cell infiltration into the lungs. Our observations suggest a strong modulatory activity of LPCs in the regulation of eosinophilic inflammation in vitro and in vivo.

Eosinophil accumulation in postnatal lung is specific to the primary septation phase of development

Type 2 immune cells and eosinophils are transiently present in the lung tissue not only in pathology (allergic disease, parasite expulsion) but also during normal postnatal development. However, the lung developmental processes underlying airway recruitment of eosinophils after birth remain unexplored. We determined that in mice, mature eosinophils are transiently recruited to the lung during postnatal days 3-14, which specifically corresponds to the primary septation/alveolarization phase of lung development. Developmental eosinophils peaked during P10-14 and exhibited Siglec-Fmed/highCD11c-/low phenotypes, similar to allergic asthma models. By interrogating the lung transcriptome and proteome during peak eosinophil recruitment in postnatal development, we identified markers that functionally capture the establishment of the mesenchymal-epithelial interface (Nes, Smo, Wnt5a, Nog) and the deposition of the provisional extracellular matrix (ECM) (Tnc, Postn, Spon2, Thbs2) as a key lung morphogenetic event associating with eosinophils. Tenascin-C (TNC) was identified as one of the key ECM markers in the lung epithelial-mesenchymal interface both at the RNA and protein levels, consistently associating with eosinophils in development and disease in mice and humans. As determined by RNA-seq analysis, naïve murine eosinophils cultured with ECM enriched in TNC significantly induced expression of Siglec-F, CD11c, eosinophil peroxidase, and other markers typical for activated eosinophils in development and allergic inflammatory responses. TNC knockout mice had an altered eosinophil recruitment profile in development. Collectively, our results indicate that lung morphogenetic processes associated with heightened Type 2 immunity are not merely a tissue "background" but specifically guide immune cells both in development and pathology.

Intersection of biology and therapeutics: type 2 targeted therapeutics for adult asthma

Asthma is a disease of reversible airflow obstruction characterised clinically by wheezing, shortness of breath, and coughing. Increases in airway type 2 cytokine activity, including interleukin-4 (IL-4), IL-5, and IL-13, are now established biological mechanisms in asthma. Inhaled corticosteroids have been the foundation for asthma treatment, in a large part because they decrease airway type 2 inflammation. However, inhaled or systemic corticosteroids are ineffective treatments in many patients with asthma and few treatment options exist for patients with steroid resistant asthma. Although mechanisms for corticosteroid refractory asthma are likely to be numerous, the development of a new class of biologic agents that target airway type 2 inflammation has provided a new model for treating some patients with corticosteroid refractory asthma. The objective of this Therapeutic paper is to summarise the new type 2 therapeutics, with an emphasis on the biological rationale and clinical efficacy of this new class of asthma therapeutics.

Contributions of Eosinophils to Human Health and Disease

The human eosinophil has long been thought to favorably influence innate mucosal immunity but at times has also been incriminated in disease pathophysiology. Research into eosinophil biology has uncovered a number of interesting contributions by eosinophils to health and disease. However, it appears that not all eosinophils from all species are created equal. It remains unclear, for example, exactly how having eosinophils benefits the human host when helminth infections in the developed world have become scarce. This review focuses on our current state of knowledge as it relates to human eosinophils. When information is lacking, we discuss lessons learned from mouse studies that may or may not directly apply to human biology and disease. It is an exciting time to be an "eosinophilosopher" because the use of biologic agents that selectively target eosinophils provides an unprecedented opportunity to define the contribution of this cell to eosinophil-associated human diseases.

Leptin Elicits In Vivo Eosinophil Migration and Activation: Key Role of Mast Cell-Derived PGD2

Eosinophils are key regulators of adipose tissue homeostasis, thus characterization of adipose tissue-related molecular factors capable of regulating eosinophil activity is of great interest. Leptin is known to directly activate eosinophils in vitro, but leptin ability of inducing in vivo eosinophilic inflammatory response remains elusive. Here, we show that leptin elicits eosinophil influx as well as its activation, characterized by increased lipid body biogenesis and LTC₄ synthesis. Such leptin-triggered eosinophilic inflammatory response was shown to be dependent on activation of the mTOR signaling pathway, since it was (i) inhibited by rapamycin pre-treatment and (ii) reduced in PI3K-deficient mice. Local infiltration of activated eosinophils within leptin-driven inflammatory site was preceded by increased levels of classical mast cell-derived molecules, including TNFα, CCL5 (RANTES), and PGD₂. Thus, mice were pre-treated with a mast cell degranulating agent compound 48/80 which was capable to impair leptin-induced PGD₂ release, as well as eosinophil recruitment and activation. In agreement with an indirect mast cell-driven phenomenon, eosinophil accumulation induced by leptin was abolished in TNFR-1 deficient and also in HQL-79-pretreated mice, but not in mice pretreated with neutralizing antibodies against CCL5, indicating that both typical mast cell-driven signals TNFα and PGD₂, but not CCL5, contribute to leptin-induced eosinophil influx. Distinctly, leptin-induced eosinophil lipid body (lipid droplet) assembly and LTC₄ synthesis appears to depend on both PGD₂ and CCL5, since both HQL-79 and anti-CCL5 treatments were able to inhibit these eosinophil activation markers. Altogether, our data show that leptin triggers eosinophilic inflammation in vivo via an indirect mechanism dependent on activation of resident mast cell secretory activity and mediation by TNFα, CCL5, and specially PGD₂.

Eosinophils Affect Antibody Isotype Switching and May Partially Contribute to Early Vaccine-Induced Immunity against Coxiella burnetii

Coxiella burnetii is an obligate intracellular Gram-negative bacterium which causes human Q fever. An acidified citrate cysteine medium (ACCM-2) has been developed which mimics the intracellular replicative niche of C. burnetii and allows axenic growth of the bacteria. To determine if C. burnetii cultured in ACCM-2 retains immunogenicity, we compared the protective efficacies of formalin-inactivated C. burnetii Nine Mile phase I (PIV) and phase II (PIIV) vaccines derived from axenic culture 7, 14, and 28 days postvaccination. PIV conferred significant protection against virulent C. burnetii as early as 7 days postvaccination, which suggests that ACCM-2-derived PIV retains immunogenicity and protectivity. We analyzed the cellular immune response in spleens from PIV- and PIIV-vaccinated mice by flow cytometry at 7 and 14 days postvaccination and found significantly more granulocytes in PIV-vaccinated mice than in PIIV-vaccinated mice. Interestingly, we found these infiltrating granulocytes to be SSChigh CD11b+ CD125+ Siglec-F+ (where SSChigh indicates a high side scatter phenotype) eosinophils. There was no change in the number of eosinophils in PIV-vaccinated CD4-deficient mice compared to the level in controls, which suggests that eosinophil accumulation is CD4+ T cell dependent. To evaluate the importance of eosinophils in PIV-mediated protection, we vaccinated and challenged eosinophil-deficient ΔdblGATA mice. ΔdblGATA mice had significantly worse disease than their wild-type counterparts when challenged 7 days postvaccination, while no significant difference was seen at 28 days postvaccination. Nevertheless, ΔdblGATA mice had elevated serum IgM with decreased IgG1 and IgG2a whether mice were challenged at 7 or 28 days postvaccination. These results suggest that eosinophils may play a role in early vaccine protection against C. burnetii and contribute to antibody isotype switching.

Intravital imaging allows real-time characterization of tissue resident eosinophils

Eosinophils are core components of the immune system, yet tools are lacking to directly observe eosinophils in action in vivo. To better understand the role of tissue resident eosinophils, we used eosinophil-specific CRE (eoCRE) mice to create GFP and tdTomato reporters. We then employed intravital microscopy to examine the dynamic behaviour of eosinophils in the healthy GI tract, mesentery, liver, lymph node, skin and lung. Given the role of eosinophils in allergic airway diseases, we also examined eosinophils in the lung following ovalbumin sensitization and challenge. We were able to monitor and quantify eosinophilic behaviours including patrolling, crawling, clustering, tissue distribution and interactions with other leukocytes. Thus, these reporter mice allow eosinophils to be examined in real-time in living animals, paving the way to further understanding the roles eosinophils play in both health and disease.

Eosinophilic esophagitis: novel concepts regarding pathogenesis and clinical manifestations

This report explores two hypotheses regarding eosinophilic esophagitis (EoE): (1) that the use of proton pump inhibitors (PPIs) might contribute to the pathogenesis of EoE by preventing peptic digestion of food allergens, by increasing gastric mucosal permeability to enable gastric absorption of those undegraded food allergens, and by causing microbial dysbiosis, and (2) that EoE, like eosinophilic gastroenteritis, might have mucosal-predominant and muscle-predominant forms, and that the muscle-predominant form of EoE might cause a variety of esophageal motility disorders including achalasia.

Autopsy and Imaging Studies of Mucus in Asthma. Lessons Learned about Disease Mechanisms and the Role of Mucus in Airflow Obstruction

Autopsy studies in fatal asthma have clearly documented the central role of airway plugging with pathologic mucus in the pathophysiology of death from asthma, but the role of mucus plugs in chronic severe asthma has been less well understood. Recently, multidetector computerized tomography imaging of the lungs has emerged as a valuable method to visualize mucus plugs in asthma. These multidetector computerized tomography data have revealed mucus plugs as a common occurrence in severe forms of asthma. In addition, an image-based mucus plug scoring system shows that mucus plugs are strongly associated with measures of airflow obstruction and with biomarkers of type 2 cytokine and eosinophilic inflammation. These data provide a rationale for treating airflow obstruction in severe asthma with mucolytics, and they also raise the possibility that treatments that target type 2 inflammation may decrease mucus plugs in asthma.

New Insights Into the Role of Tissue Eosinophils in the Progression of Colorectal Cancer: A Literature Review

INTRODUCTION

Amongst the inflammatory cells implicated in the immune surveillance of colorectal cancer, a growing body of evidence suggests a role for eosinophils in carcinogenesis. We aimed to review the value of tumour-associated tissue eosinophilia (TATE) in the prognosis of colorectal cancer emphasizing the identification and measurement of tissue-infiltrating eosinophils and their association with the clinicopathological features of the disease.

MATERIAL AND METHODS

We used PubMed and Web of Science search engines to retrieve studies that looked at the association between tissue eosinophils and colorectal cancer prognosis.

RESULTS

We selected 15 studies for our review. In the majority of the studies, eosinophils were identified in hematoxylin-eosin stained sections and scores were generated for analysis. Most of the studies pointed to tumour-associated tissue eosinophilia as a favourable prognostic marker in colorectal cancer and found an inverse association between eosinophil count and the metastatic potential of these neoplasms. The association between tumour-associated tissue eosinophilia and established prognostic markers of colorectal cancer was assessed in some studies, with inconsistent results. Additionally, tumour-associated tissue eosinophilia decreased with the adenoma-carcinoma progression of colorectal lesions.

DISCUSSION

Several mechanisms have been proposed regarding eosinophil chemoatraction to tumour tissues and eosinophil-cancer cell cross-talk, suggesting that eosinophils are actively involved in colorectal cancer progression. Although a scoring system is still lacking, tumour-associated tissue eosinophilia meets the criteria of a convenient histopathological prognosticator in colorectal cancer.

CONCLUSION

Collectively, current evidence associates the presence of eosinophils in the colorectal cancer microenvironment with the modulation of tumour progression. The clinical impact of this finding deserves future research.

Eosinophils Mediate Tissue Injury in the Autoimmune Skin Disease Bullous Pemphigoid

Eosinophils are typically associated with unique inflammatory settings, including allergic inflammation and helminth infections. However, new information suggests that eosinophils contribute more broadly to inflammatory responses and participate in local immune regulation and the tissue remodeling/repair events linked with a variety of diseases. Eosinophilic infiltration has long been a histologic hallmark of bullous pemphigoid (BP), a subepidermal autoimmune blistering disease characterized by autoantibodies directed against basement membrane protein BP180. However, the exact role of eosinophils in disease pathogenesis remains largely unknown. We show here that eosinophils are necessary for IgE autoantibody-mediated BP blister formation in a humanized IgE receptor mouse model of BP. Disease severity is IgE dose dependent and correlates with the degree of eosinophil infiltration in the skin. Furthermore, IgE autoantibodies fail to induce BP in eosinophil-deficient mice, confirming that eosinophils are required for IgE-mediated tissue injury. Thus, eosinophils provide the cellular link between IgE autoantibodies and skin blistering in this murine model of BP. These findings suggest a role for eosinophils in autoimmune disease and have important implications for the treatment of BP and other antibody-mediated inflammatory and autoimmune diseases.

Activation of Eosinophils and Mast Cells in Functional Dyspepsia: an Ultrastructural Evaluation

We recently identified mucosal mast cell and eosinophil hyperplasia in association with a duodenal impaired barrier function in functional dyspepsia (FD). We aimed to further describe the implication of these immune cells by assessing their activation state at the ultrastructural level and by evaluating the association between impaired epithelial integrity and immune activation. Duodenal biopsies were obtained from 24 FD patients and 37 healthy controls. The ultrastructure of mast cells and eosinophils was analyzed by transmission electron microscopy. Transepithelial electrical resistance and paracellular permeability were measured to evaluate epithelial barrier function. The type of degranulation in eosinophils and mast cells was piecemeal. Eosinophils displayed higher degree of degranulation in FD patients than in controls (p < 0.0001). Quantification revealed a decreased granular density in eosinophils of FD patients (p < 0.0001). The degree of degranulation in mast cells was similar in both groups. However, a more heterogeneous profile was found in the FD group (p < 0.0001). No association between epithelial integrity and the number and activation state of mucosal eosinophils and mast cells was found. We demonstrated ultrastructural changes in degranulation state of eosinophils and mast cells, suggesting that eosinophil and mast cell activation play a role in the pathophysiology of FD.

Characterization of Cotton Rat (Sigmodon hispidus) Eosinophils, Including Their Response to Respiratory Syncytial Virus Infection

Eosinophils have been postulated to play a protective role against infection with respiratory syncytial virus (RSV), increase the severity of allergic asthma during respiratory viral infection, and drive vaccine-enhanced disease. To address these questions in the cotton rat model of RSV infection, we characterized cotton rat eosinophils by electron microscopy as well as by bronchoalveolar lavage and histology of lung sections. Using these methods, we demonstrated that eosinophils comprise approximately half of all cells in the bronchoalveolar lavage fluids from cotton rats. The function of these cells was comparable to that of eosinophils of other species. Ex vivo, eosinophils stimulated with calcium ionophores secreted eosinophil peroxidase. In vivo, treatment with house dust mite antigen increased eosinophil numbers in lung. Infection with Staphylococcus aureus lead to a marked increase in neutrophils without an increase in eosinophils, and eosinophil numbers were not influenced by infection with influenza virus or measles virus. Similarly, infection with RSV did not result in an increase in eosinophils. Lastly, RSV infection did not increase eosinophil recruitment into the lung after challenge with house dust mite antigen, but it did increase eosinophil recruitment into the lungs of cotton rats previously immunized with formalin-inactivated RSV vaccine, thus contributing to vaccine-enhanced disease.

Activation of human eosinophils with palladium nanoparticles (Pd NPs): importance of the actin cytoskeleton in Pd NPs-induced cellular adhesion

Palladium (Pd) is known to be released into the environment in the fine and ultrafine (at the nanoscale) airborne particle fractions mainly from automobile catalytic converters leading to an increase human exposure to this noble metal. It was reported that Pd can induce allergic reactions in individuals exposed to it via different ways. Some studies reported an increased number of eosinophils into airways following NP exposure in vivo in rodent models of allergies and inflammation. Knowing the importance of eosinophils in allergies, asthma and other lung diseases, it is surprising to observe that the direct effect of Pd at the nanoscale in eosinophils has been poorly documented. The aim of this study was to determine how Pd NPs will affect the biology of human eosinophils. Characterization of Pd NPs by dynamic light scattering indicates the presence of some aggregates when suspended in diverse solutions used here for the different experiments. Pd NPs did not significantly induce cell necrosis and apoptosis in eosinophils (0.5-150μg/ml) as assessed by trypan blue exclusion assay, flow cytometry after staining with FITC-annexin V and propidium iodide and by morphological observations by optical microscopy. PD NPs, unlike the positive controls, did not induce reactive oxygen species (ROS) but were found to target the actin cytoskeleton, since actin was differently re-located intracellularly when compared to untreated cells as determined by fluorescence microscopy. Clearly, Pd NPs were found to increase adhesion of eosinophils onto human endothelial EA.hy926 cells. Using cytochalasin D, a cell-permeable and potent inhibitor of actin polymerization, this ability to increase adhesion was drastically reversed. Our results indicate that Pd NPs can target the cytoskeleton and increase the adhesion of human eosinophils by an actin-dependent mechanism. These findings show that human eosinophils can be activated by Pd NPs emphasizing the importance of fully investigating how these NPs could alter the biology of human cells involved in allergies, asthma and other lung diseases as well as in various other inflammatory disorders.

Functions of tissue-resident eosinophils

Eosinophils are a prominent cell type in particular host responses such as the response to helminth infection and allergic disease. Their effector functions have been attributed to their capacity to release cationic proteins stored in cytoplasmic granules by degranulation. However, eosinophils are now being recognized for more varied functions in previously underappreciated diverse tissue sites, based on the ability of eosinophils to release cytokines (often preformed) that mediate a broad range of activities into the local environment. In this Review, we consider evolving insights into the tissue distribution of eosinophils and their functional immunobiology, which enable eosinophils to secrete in a selective manner cytokines and other mediators that have diverse, 'non-effector' functions in health and disease.

Ozone-induced eosinophil recruitment to airways is altered by antigen sensitization and tumor necrosis factor-α blockade

Ozone is an atmospheric pollutant that causes lung inflammation and airway hyperresponsiveness. Ozone's effects occur in two distinct phases that are mediated by different populations of eosinophils. In the acute phase 1 day after exposure, mature airway-resident eosinophils alter parasympathetic nerve function that results in airway hyperresponsiveness. At this time point, the severity of hyperresponsiveness correlates with the number of eosinophils in close proximity to airway nerves, but not with eosinophils in bronchoalveolar lavage. Three days later, newly divided eosinophils are recruited to airways by a tumor necrosis factor-α-dependent mechanism. These new eosinophils paradoxically attenuate ozone-induced airway hyperresponsiveness. Ozone's effects on airway tissue eosinophils and nerve-associated eosinophils 3 days after exposure are unknown. Thus, we tested ozone's effects on eosinophils in airway subepithelium and around airway nerves 1 and 3 days after ozone in nonsensitized and ovalbumin-sensitized guinea pigs with or without the tumor necrosis factor-α antagonist, etanercept, and compared changes in eosinophils with ozone-induced airway hyperresponsiveness. More eosinophils were present in small, noncartilaginous airways and along small airway nerves compared to large cartilaginous airways in all treatment groups. The number of airway and nerve-associated eosinophils were unaffected 1 day after ozone exposure, whereas significantly fewer airway eosinophils were present 3 days later. Airway and nerve-associated eosinophils were also decreased in small airways 3 days after ozone in sensitized animals. These changes were blocked by etanercept. Airway eosinophils, but not nerve-associated or bronchoalveolar lavage eosinophils correlated with airway hyperresponsiveness 3 days after ozone. Our findings indicate ozone causes persistent alterations in airway eosinophils and reinforce the importance of characterizing eosinophils' effects within distinct airway compartments.

Microenvironmental regulation of tumour angiogenesis

Tumours display considerable variation in the patterning and properties of angiogenic blood vessels, as well as in their responses to anti-angiogenic therapy. Angiogenic programming of neoplastic tissue is a multidimensional process regulated by cancer cells in concert with a variety of tumour-associated stromal cells and their bioactive products, which encompass cytokines and growth factors, the extracellular matrix and secreted microvesicles. In this Review, we discuss the extrinsic regulation of angiogenesis by the tumour microenvironment, highlighting potential vulnerabilities that could be targeted to improve the applicability and reach of anti-angiogenic cancer therapies.

The role of B cell Activating Factor (BAFF) expression on pathogenesis of nasal polyp in chronic rhinosinusitis with nasal polyposis

BACKGROUND

B cells, plasma cells, and local immunoglobulins, are important as a mucosal immune barrier function, and tend to increase in patients with chronic rhinosinusitis with nasal polyposis (CRSwNP). However, their association with eosinophils' aggregation has not been fully understood. The objectives of this study was to explore whether BAFF expression in the subepithelial area in nasal polyp tissues of CRSwNP was associated with eosinophils' accumulation, and also to evaluate cells which cells produce BAFF.

METHODOLOGY

Immunohistochemical and immunofluorescence staining were used to analyse expression of BAFF, CD20, immunoglobulin A (IgA) and a proliferation inducing ligand (APRIL) on nasal tissues from CRSwNP patients to control subjects. To identify the relationship between BAFF and tissue eosinophilia, CRSwNP subjects were divided into eosinophilic polyp and non-eosinophilic groups. Double immunofluorescence analysis for BAFF and CD11c or CD11b was performed to identify cells producing BAFF.

RESULTS

The numbers of BAFF, CD20, and IgA-positive cells in the subepithelial area were significantly higher in the CRSwNP group (both eosinophilic polyps and non-eosinophilic polyps. There were statistically significant correlations between the number of BAFF and CD20-positive cells, CD20 and IgA-positive cells, and BAFF and IgA-positive cells. CD11b-positive were co-localized with BAFF positive cells.

CONCLUSION

The subepithelial expression of BAFF was associated with increased number of B cells and plasma cells, and increased production of IgA in the patients with CRSwNP, especially eosinophilic nasal polyps. Therefore, BAFF-induced IgA production may be associated with eosinophils' aggregation and degranulation, which cause aggravation of tissue inflammation and finally polyp formation. The expression of BAFF in the subepithelial area may be associated with innate inflammatory cells (CD11b+ cells), such as monocytes, granulocytes, macrophages, and natural killer cells.

Eosinophil fungal rhinosinusitis caused by Fusarium infection secondary to odontogenic maxillary sinus disease: when collaboration between otolaryngologist and allergologist leads to the correct diagnosis and therapy

Rhinitis and sinusitis usually coexist and are concurrent in most individuals; thus, the correct terminology is now "rhinosinusitis". On the basis of numerous causative factors, often co-existing in the same patient, the diagnosis of rhinosinusitis is also made by a wide variety of practitioners (allergologists, otolaryngologists, pulmonologists, primary care physicians, paediatricians, and many others). Approximately 5-15% of the population suffers from chronic rhinosinusitis, and in 10-12% of them, it is of dental origin. The treatment of odontogenic maxillary sinus disease is directed to the management of the rhinosinusitis and of the odontogenic source. The widespread use of dental implants and reconstructive procedures for dental implant placement has led to new types of complication, as in this case report, due to chronic eosinophilic rhinosinusitis secondary to Fusarium infection in the maxillary sinus. The patient was initially evaluated by the allergologist, and subsequently successfully treated by the otolaryngologist with Functional Endoscopic Sinus Surgery. The advantages of endoscopic sinus surgery include more accurate visualization, no external incision, reduced soft tissue dissection, and reduced hospital stay. Chronic maxillary sinusitis of dental origin is a common disease that requires treatment of the sinusitis as well as of the odontogenic source.

[Effect of heat shock factor 1 on airway hyperresponsiveness and airway inflammation in mice with allergic asthma]

OBJECTIVE

To investigate the effect of heat shock factor 1 (HSF1) on airway hyperresponsiveness and airway inflammation in mice with asthma and possible mechanisms.

METHODS

A total of 36 mice were randomly divided into four groups: control, asthma, HSF1 small interfering RNA negative control (siHSF1-NC), and siHSF1 intervention (n=9 each). Ovalbumin (OVA) sensitization and challenge were performed to induce asthma in the latter three groups. The mice in the siHSF1-NC and siHSF1 groups were treated with siHSF1-NC and siHSF1, respectively. A spirometer was used to measure airway responsiveness at 24 hours after the last challenge. The direct count method was used to calculate the number of eosinophils. ELISA was used to measure the serum level of OVA-specific IgE and levels of interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-13 (IL-13), and interferon-γ (IFN-γ) in lung tissues and bronchoalveolar lavage fluid (BALF). Quantitative real-time PCR was used to measure the mRNA expression of HSF1 in asthmatic mice. Western blot was used to measure the protein expression of HSF1, high-mobility group box 1 (HMGB1), and phosphorylated c-Jun N-terminal kinase (p-JNK).

RESULTS

The asthma group had significant increases in the mRNA and protein expression of HSF1 compared with the control group (P<0.05). The siHSF1 group had significantly reduced mRNA and protein expression of HSF1 compared with the siHSF1-NC group (P<0.05). The knockdown of HSF1 increased airway wall thickness, airway hyperresponsiveness, OVA-specific IgE content, and the number of eosinophils (P<0.05). Compared with the siHSF1-NC group, the siHSF1 group had significantly increased levels of IL-4, IL-5, and IL-13 and significantly reduced expression of IFN-γ in lung tissues and BALF (P<0.05), as well as significantly increased expression of HMGB1 and p-JNK (P<0.05).

CONCLUSIONS

Knockdown of HSF1 aggravates airway hyperresponsiveness and airway inflammation in asthmatic mice, and its possible mechanism may involve the negative regulation of HMGB1 and JNK.

IL-33-driven ILC2/eosinophil axis in fat is induced by sympathetic tone and suppressed by obesity

Group 2 innate lymphoid cells (ILC2s) in white adipose tissue (WAT) promote WAT browning and assist in preventing the development of obesity. However, how ILC2 in adipose tissue is regulated remains largely unknown. Here, our study shows that ILC2s are present in brown adipose tissue (BAT) as well as subcutaneous and epididymal WAT (sWAT and eWAT). The fractions of ILC2s, natural killer T (NKT) cells and eosinophils in sWAT, eWAT and BAT are significantly decreased by high-fat-diet (HFD) feeding and leptin deficiency-induced obesity. Consistent with this, the adipose expression and circulating levels of IL-33, a key inducing cytokine of ILC2, are significantly downregulated by obesity. Furthermore, administration of IL-33 markedly increases the fraction of ILC2 and eosinophil as well as the expression of UCP1 and tyrosine hydroxylase (TH), a rate-limiting enzyme in catecholamine biosynthesis, in adipose tissue of HFD-fed mice. On the other hand, cold exposure induces the expression levels of IL-33 and UCP1 and the population of ILC2 and eosinophil in sWAT, and these promoting effects of cold stress are reversed by neutralization of IL-33 signaling in vivo Moreover, the basal and cold-induced IL-33 and ILC2/eosinophil pathways are significantly suppressed by sympathetic denervation via local injection of 6-hydroxydopamine (6-OHDA) in sWAT. Taken together, our data suggest that the ILC2/eosinophil axis in adipose tissue is regulated by sympathetic nervous system and obesity in IL-33-dependent manner, and IL-33-driven ILC2/eosinophil axis is implicated in the development of obesity.

T-Cell Lymphoma with Eosinophilic Infiltration Involving the Intestinal Tract in 11 Dogs

Among the intestinal tumors of hematopoietic cell origin, lymphoma is the most common in the dog. Herein, we characterized the clinical and pathologic features of 11 dogs (average age, 10.6 ± 2.5 years) with T-cell lymphoma of the intestinal tract with eosinophil infiltrates. No sex predominance was apparent. All had localized tumor masses in the small intestine. Grossly, the intestinal wall was thickened, and the lumen of the affected intestine was usually narrowed. Microscopically, we observed transmural diffuse invasion of round to pleomorphic tumor cells. Tumor cells showed varying morphology, from scanty to abundant cytoplasm, and round to ovoid nuclei with scattered to dense chromatin. In seven of the dogs, tumor cells had infiltrated into the epithelium. All showed infiltration of eosinophils and all 11 tumors had a T-cell phenotype (CD3+,CD79-). Only one tumor stained positive for the mast cell marker c-kit and none was positive for mast cell tryptase. We did not observe ultrastructurally apparent granules in any of the tumor cells. These results suggest that, in dogs, T-cell lymphomas of intestinal origin resemble mast cell tumors of intestinal origin with respect to cell structure and eosinophil infiltration. Therefore, in the absence of epitheliotropism, it is difficult to confirm the differential diagnosis without immunostaining for mast cell and lymphocyte markers, including mast cell tryptase, c-kit, CD3, and CD79.

Cylindromatosis (Cyld) gene mutation in T cells promotes the development of an IL-9-dependent allergic phenotype in experimental asthma

Cylindromatosis (CYLD) is a ubiquitously expressed deubiquitinating enzyme which removes activating ubiquitin residues from important signaling molecules of the NF-κB pathway. In CYLD^ex7/8 transgenic mice, a naturally occurring short isoform (sCYLD) is overexpressed in the absence of full length CYLD, leading to excessive NF-κB activity. Herein, we investigated the impact of the CYLD^ex7/8 mutation selectively in T cells on the development of experimental allergic airway disease induced by sensitization and challenge with ovalbumin. Compared with their wildtype littermates, mice bearing the T cell-specific mutation (CD4⁺CYLD^ex7/8) display stronger eosinophilia and mucus production in the lungs and higher IgE serum levels. The reason for these observations is excessive production of T cell-derived IL-9, a cytokine to whom allergy-promoting properties were ascribed. Consequently, blockade of IL-9 in CD4⁺CYLD^ex7/8 mice alleviates the development of disease symptoms. Thus, by polarization of the T cell cytokine response, sCYLD can favor the development of allergic airway disease.

The role of eosinophils in stroke: a pilot study

OBJECTIVE

To evaluate the factors that may have an impact on the prognosis of ischemic stroke.

PATIENTS AND METHODS

The study included 973 patients who were diagnosed with an ischemic stroke. The patients were divided into 6 groups according their eosinophil counts' level and occurred times. All patients were supervised by NIHSS score in three months.

RESULTS

Baseline characteristics of all study groups were comparable. Thirty-four patients in group 2 and group 5 had higher eosinophil counts. In addition, the patients experienced impaired function on the face, but no impairment of limbs. All patients in these groups recovered quicker than the other groups (p < 0.05). Furthermore, 169 patients in both group 3 and group 6 had lower eosinophil counts. These patients experienced functional impairment in limbs and difficulty recovering from the disease. The NIHSS score was lower in both group 2 and group 5, compared with group 3 and group 6 (p < 0.05).

CONCLUSIONS

This study suggests that eosinophil counts may have a significant impact on outcomes in stroke patients. The data underscore the importance in further investigating eosinophil dysregulation as well as the potential relationship between eosinophil dysregulation and organ functions in stroke patients.

Family Functioning, Eosinophil Activity, and Symptoms in Children With Asthma

OBJECTIVE

We examined prospective connections among parental depressive symptoms, family dysfunction, and eosinophil activity in children with asthma.

METHODS

81 children with asthma and their parents completed two laboratory visits across a 1-year period. At baseline and 1 year later, parents reported about their depressive symptoms and family dysfunction. We collected peripheral blood in children to measure eosinophil counts and eosinophil cationic protein. Following visits, children recorded their asthma symptoms for 2 weeks.

RESULTS

After controlling for demographic and biomedical covariates, a significant T1 × T2 Family Dysfunction interaction emerged, suggesting that the links between family dysfunction at T1 and eosinophil counts and activity at T2 depended on family functioning at T2. Parental depressive symptoms were unrelated to eosinophil activity and asthma symptoms.

CONCLUSIONS

These findings suggest that improvements in family functioning are associated with decreases in eosinophil activity, which may contribute to inflammatory processes that affect airway function.

Histamine 1 Receptor Blockade Enhances Eosinophil-Mediated Clearance of Adult Filarial Worms

Filariae are tissue-invasive nematodes that cause diseases such as elephantiasis and river blindness. The goal of this study was to characterize the role of histamine during Litomosoides sigmodontis infection of BALB/c mice, a murine model of filariasis. Time course studies demonstrated that while expression of histidine decarboxylase mRNA increases throughout 12 weeks of infection, serum levels of histamine exhibit two peaks—one 30 minutes after primary infection and one 8 weeks later. Interestingly, mice treated with fexofenadine, a histamine receptor 1 inhibitor, demonstrated significantly reduced worm burden in infected mice compared to untreated infected controls. Although fexofenadine-treated mice had decreased antigen-specific IgE levels as well as lower splenocyte IL-5 and IFNγ production, they exhibited a greater than fourfold rise in eosinophil numbers at the tissue site where adult L. sigmodontis worms reside. Fexofenadine-mediated clearance of L. sigmodontis worms was dependent on host eosinophils, as fexofenadine did not decrease worm burdens in eosinophil-deficient dblGATA mice. These findings suggest that histamine release induced by tissue invasive helminths may aid parasite survival by diminishing eosinophilic responses. Further, these results raise the possibility that combining H1 receptor inhibitors with current anthelmintics may improve treatment efficacy for filariae and other tissue-invasive helminths.

Filariae are tissue-invasive parasitic roundworms that infect over 100 million people worldwide and cause debilitating conditions such as river blindness and elephantiasis. One of the major factors limiting our ability to eliminate these infections is the lack of drugs that kill adult worms when given as a short course therapy. Additionally, the mechanisms by which adult worms are cleared from infected individuals remains poorly understood. In this study, we demonstrate that treatment of infected mice with fexofenadine, an inhibitor of histamine receptor 1, significantly reduces adult worm numbers through a mechanism dependent on host eosinophils. These findings suggest that histamine release induced by parasitic worms may aid parasite survival by decreasing eosinophilic responses. Further, as antihistamines are generally safe medications, these results raise the possibility that antihistamine therapy may be useful either alone, or potentially in combination with other antifilarial medications such as diethylcarbamazine (DEC), to eliminate adult filarial worms from infected individuals.