The term “eosinophilic” asthma (EA) generally refers to the clinical inflammatory phenotype of asthma wherein a significant number of sputum, airway, and/or blood eosinophils are present. Conversely, individuals with “noneosinophilic” asthma (NEA) may still demonstrate low numbers of eosinophils, but the dominant inflammatory cell type may include neutrophils, mixed granulocyte inflammatory cells, or very few inflammatory cells, termed paucigranulocytic inflammation. Although the mechanisms driving EA are becoming clearer, by contrast much less attention has been given to the underlying mechanisms that drive NEA, leading to a lack of available therapies for this patient population. Although “phenotype” refers to the observable characteristics of disease in an individual, by “endotypes” we mean the specific biological mechanism that causes those observed properties of any given phenotype. Understanding the manifold mechanisms or endotypes contributing to EA and NEA and the resulting clinical phenotypes derived from these endotypes will lead to novel treatment options and provide an opportunity for more precise and tailored treatments. This review highlights the mechanisms currently believed to underlie the recognized subphenotypes of EA and NEA and briefly discusses their clinical presentations as well as implications for treatment. Definition of Eosinophilic and Noneosinophilic Asthma

/pdf/eosinophilic-and-noneosinophilic-asthma-3q3mikamn1.pdf

Eosinophilic and Noneosinophilic Asthma

Severe asthma is a debilitating and treatment refractory disease. As many as half of these patients have complex neutrophil-predominant lung inflammation that is distinct from milder asthma with type 2 eosinophilic inflammation. New insights into severe asthma pathogenesis are needed. Concomitant exposure of mice to an aeroallergen and endotoxin during sensitization resulted in complex neutrophilic immune responses to allergen alone during later airway challenge. Unlike allergen alone, sensitization with allergen and endotoxin led to NETosis. In addition to neutrophil extracellular traps (NETs), enucleated neutrophil cytoplasts were evident in the lungs. Surprisingly, allergen-driven airway neutrophilia was decreased in peptidyl arginine deiminase 4-deficient mice with defective NETosis but not by deoxyribonuclease treatment, implicating the cytoplasts for the non-type 2 immune responses to allergen. Neutrophil cytoplasts were also present in mediastinal lymph nodes, and the cytoplasts activated lung dendritic cells in vitro to trigger antigen-specific interleukin-17 (IL-17) production from naive CD4+ T cells. Bronchoalveolar lavage fluid from patients with severe asthma and high neutrophil counts had detectable NETs and cytoplasts that were positively correlated with IL-17 levels. Together, these translational findings have identified neutrophil cytoplast formation in asthmatic lung inflammation and linked the cytoplasts to T helper 17-mediated neutrophilic inflammation in severe asthma.

/pdf/neutrophil-cytoplasts-induce-th17-differentiation-and-skew-1qop9od45e.pdf

Neutrophil cytoplasts induce TH17 differentiation and skew inflammation toward neutrophilia in severe asthma.

Glucocorticoids are hormones that regulate several functions in living organisms and synthetic glucocorticoids are the most powerful anti-inflammatory pharmacological tool that is currently available. Although glucocorticoids have an immunosuppressive effect on immune cells, they exert multiple and sometimes contradictory effects on neutrophils. From being extremely sensitive to the anti-inflammatory effects of glucocorticoids to resisting glucocorticoid-induced apoptosis, neutrophils are proving to be more complex than they were earlier thought to be. The aim of this review is to explain these complex pathways by which neutrophils respond to endogenous or to exogenous glucocorticoids, both under physiological and pathological conditions.

https://www.mdpi.com/1422-0067/19/12/4090/pdf

How Glucocorticoids Affect the Neutrophil Life

Chronic obstructive pulmonary disease (COPD) is a common inflammatory lung disease. Sialic acid-binding immunoglobulin-type lectins 9 (Siglec-9) is predominantly expressed on innate immune cells and has been shown to exert regulatory effect on immune cells through glycan recognition. Soluble Siglec-9 (sSiglec-9), the extracellular region of Siglec-9, might fulfill its function partly by competitive inhibiting siglec-9 binding to its ligands; however, the role of Siglec-9 and sSiglec-9 in the pathogenesis COPD remain largely unknown. In this study, we showed that Siglec-9 expression in alveolar and peripheral blood neutrophil were increased in COPD patients by immunofluorescence and flow cytometry, respectively. Plasma levels of sSiglelc-9 were elevated in COPD patients by ELISA. In vitro, Siglec-9 expression and/or sSiglelc-9 levels were up-regulated by cigarette smoke extract (CSE), lipopolysaccharide (LPS), some cytokines, and dexamethasone (DEX). Recombinant sSiglce-9 increased oxidative burst in neutrophil and enhanced neutrophil chemotaxis toward IL-8 independent on CXCR1 and CXCR2 expression, but it did not affect neutrophil apoptosis or secretions of inflammatory cytokines. In conclusion, Siglec-9 was complementarily increased to induce a negative feedback loop to limit neutrophil activation in COPD, sSiglce-9 enhanced neutrophil ROS and chemotaxis toward IL-8 likely via competitively inhibiting ligands binding to Siglec-9.

/pdf/increased-expression-of-siglec-9-in-chronic-obstructive-2moz4ktq1d.pdf

Increased expression of Siglec-9 in chronic obstructive pulmonary disease

Background Chronic rhinosinusitis (CRS) can be divided to CRS without nasal polyps (CRSsNP) and eosinophilic and non-eosinophilic CRS with nasal polyps (CRSwNP). There is little evidence on the efficacy of glucocorticoids and macrolides in different phenotypic patients. The aim of this study was to compare the benefit of glucocorticoids and macrolides following endoscopic sinus surgery (ESS) in different phenotypic CRS. Methods This study was a prospective single-blind comparative effectiveness trial. A total of 187 Chinese patients with CRS were stratified to CRSsNP and eosinophilic and non-eosinophilic CRSwNP group and then randomized to receive fluticasone propionate nasal spray at 200 microgram or clarithromycin tablet at 250 mg once daily for 3 months after ESS. Oral prednisone was given as a rescue therapy after the stop of study medication. Patients were assessed before ESS and 1, 3, 6 and 12 months after dosing. Symptom severity was scored by patients using visual analog scale method and endoscopic findings were scored by the senior physician blinded to treatment according to European Position Paper on Rhinosinusitis and Nasal polyps 2012. Results The total and individual symptom scores, and total and individual endoscopic domain scores were reduced significantly after ESS in both medication groups, whereas no significant difference was observed for two medications at most follow-up visits in each subtype of CRS. No difference in the frequency of subjects with rescue therapy or refractory CRS was found between two medication groups either. Conclusions We could not show significant difference of effect between fluticasone propionate and clarithromycin in the post-operative treatment for CRSsNP and eosinophilic and non-eosinophilic CRSwNP patients.

/pdf/comparison-of-efficacy-of-fluticasone-propionate-versus-533e935pu1.pdf

Comparison of efficacy of fluticasone propionate versus clarithromycin for postoperative treatment of different phenotypic chronic rhinosinusitis: a randomized controlled trial.

In the lung, melanoma is mostly arranged as patterns of multiple nodules, solitary nodules, or miliary invasions. Very rarely, it also displays a “crazy paving” pattern (also described as a “paving stone,” “flagstone,” or “slabstone” pattern), which is rarer still in discrete bilateral nodules. This pattern is considered to be caused by pulmonary alveolar proteinosis, but its association with various diseases is unclear. A 60-year-old man was diagnosed with pulmonary melanoma. Computed tomography revealed discrete bilateral nodules surrounded by a “paving” pattern. A literature review found more than 40 types of diseases that have presented with “paving” patterns in the lung—predominantly pulmonary alveolar proteinosis, viral pneumonia, exogenous lipoid pneumonia, bacterial pneumonia, pulmonary alveolar microlithiasis, interstitial pneumonia, ARDS, squalene aspiration pneumonia, radiation pneumonitis, drug-induced pneumonitis, pulmonary leptospirosis, pulmonary hemorrhage, and pulmonary nocardiosis. We describe the first case of pulmonary melanoma in the form of discrete bilateral nodules accompanied with a computed tomography paving pattern. Although pulmonary paving patterns are rare, more than 40 diseases reportedly display them; clinicians should consider melanoma of the lung in differential diagnoses for patients who show such a pattern.

/pdf/pulmonary-melanoma-and-crazy-paving-patterns-in-chest-images-565wluol50.pdf

Pulmonary melanoma and “crazy paving” patterns in chest images: a case report and literature review

BACKGROUND Innate immunity has been thought to be involved in asthma pathogenesis. Pentraxins, acting as soluble pattern recognition molecules, play an important role in humoral innate immunity. Asthma is a heterogeneous inflammatory disease of airways and can be classified as eosinophilic or non-eosinophilic asthma. OBJECTIVE To investigate whether pentraxin levels differ in subjects with eosinophilic versus non-eosinophilic asthma. Furthermore, to access the predictive performance of pentraxin levels for discriminating asthma inflammatory phenotypes. METHODS A total of 80 asthmatic patients and 24 healthy control subjects underwent sputum induction at study inclusion. Differential leucocyte counts were performed on selected sputum. Plasma C-reactive protein (CRP), serum amyloid P (SAP), pentraxin 3 (PTX3), and sputum SAP, PTX3, IL-8 levels were determined by enzyme-linked immunosorbent assay. RESULTS Subjects with non-eosinophilic asthma had significantly increased pentraxin levels compared with those with eosinophilic asthma and healthy controls, with median (interquartile range) plasma CRP levels of 0.86 (0.28-2.07), 0.26 (0.14-0.85), and 0.15 (0.09-0.45)mg/L (P < .001), respectively, plasma SAP levels of 33.69 (19.79-58.39), 19.76 (16.11-30.58), and 20.06 (15.68-31.11)mg/L (P = .003), respectively, and sputum PTX3 levels of 4.9 (1.35-18.72), 0.87 (0.30-2.07), and 1.08 (0.31-4.32)ng/mL (P < .001), respectively. Conversely, sputum SAP concentrations of eosinophilic asthmatics (median, 21.49 ng/mL; IQR, 6.86-38.79 ng/mL) were significantly higher than those of non-eosinophilic patients (median, 8.15 ng/mL; IQR, 2.82-18.01 ng/mL) and healthy controls (median, 8.79 ng/mL; IQR, 2.00-16.18 ng/mL). Asthma patients with high plasma CRP (P = .004), SAP (P = .005) and sputum PTX3 levels (P < 0.001) also had significantly lower sputum eosinophil percentages. Sputum PTX3 levels had the best power (11.18-fold, P < .001) to predict non-eosinophilic airway inflammation in asthma patients. CONCLUSION AND CLINICAL RELEVANCE Pentraxin levels differed significantly between patients with non-eosinophilic asthma and those with eosinophilic asthma. Furthermore, elevated pentraxin expressions may predict non-eosinophilic airway inflammation in asthmatic patients.

Pentraxin levels in non-eosinophilic versus eosinophilic asthma.

Comparative study of two models of combined pulmonary fibrosis and emphysema in mice.

Steroid resistant (SR) asthma is characterized by persistent airway inflammation that fails to resolve despite treatment with high doses of corticosteroids. Furthermore, SR patient airways show increased numbers neutrophils, which are less responsive to glucocorticoid. The present study seeks to determine whether dexamethasone (DEX) has different effect on neutrophils from steroid sensitive (SS) asthmatics compared to SR asthmatics. Adults with asthma (n = 38) were classified as SR or SS based on changes in lung FEV1% following a one-month inhaled corticosteroid (ICS) treatment. Blood samples were collected from all patients during their first visit of the study. Neutrophils isolated from the blood were cultured with dexamethasone and/or atopic asthmatic serum for 18 h. The mRNA expression of mitogen-activated protein kinase phosphatase-1 (MKP-1), a glucocorticoid transactivation target, and glucocorticoid-induced transcript 1 (GLCCI1), an early marker of glucocorticoid-induced apoptosis whose expression was associated with the response to inhaled glucocorticoids in asthma , was determined by real-time PCR, and ELISA was used to assess the pro-inflammatory cytokine IL-8 levels in the supernatant. Constitutive neutrophil apoptosis was detected by flow cytometry. DEX significantly induced MKP-1 expression in both patients with SS and SR patients in a concentration-dependent manner, but greater induction was observed for SS patients at a low concentration (10−6 M). Asthmatic serum alone showed no MKP-1expression, and there was impaired induction of MKP-1 by DEX in SR asthma patients. The expression of GLCCI1 was not induced in neutrophils with DEX or DEX/atopic asthmatic serum combination. Greater inhibition of IL-8 production was observed in neutrophils from patients with SS asthma treated with DEX/atopic asthmatic serum combination compared with SR asthma patients, though DEX alone showed the same effect on neutrophils from SS and SR asthma patients. Meanwhile, DEX dependent inhibition of constitutive neutrophil apoptosis was similar between SS asthma and SR asthma patients. DEX exerted different effects on neutrophils from patients with SS asthma and SR asthma, which may contribute to glucocorticoid insensitivity.

https://link.springer.com/content/pdf/10.1186%2Fs12931-016-0462-0.pdf

Impaired anti-inflammatory action of glucocorticoid in neutrophil from patients with steroid-resistant asthma

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Pulmonary melanoma and “crazy paving” patterns in chest images: a case report and literature review

Pentraxin levels in non-eosinophilic versus eosinophilic asthma.

Comparative study of two models of combined pulmonary fibrosis and emphysema in mice.

Impaired anti-inflammatory action of glucocorticoid in neutrophil from patients with steroid-resistant asthma