Addressing diagnostic dilemmas in eosinophilic esophagitis using esophageal epithelial eosinophil-derived neurotoxin.

OBJECTIVES: Eosinophil-derived neurotoxin (EDN) is a viable marker of eosinophilic esophagitis (EoE) disease activity. We studied the utility of measuring EDN from esophageal epithelial brushings for diagnosing EoE, focusing on two scenarios: (1) cases of exclusive distal eosinophilia and (2) cases of discrepancy between endoscopy and histology. METHODS: Records of patients who underwent esophagogastroduodenoscopy (EGD) with EDN measured via esophageal brushings at Arnold Palmer Hospital for Children in Orlando, Florida from January 2014 to October 2018 were retrospectively reviewed. Demographics, clinical, endoscopic, and histologic data were collected. RESULTS: We reviewed 231 patient records (66.7% male, mean age 10.3 years, range 1-22 years). EDN values correlated with endoscopic reference score (EREFS) and peak eosinophil count (PEC) (Spearman's rho = 0.756 (p < 0.001) and 0.824 (p < 0.001) respectively). Average PEC, EREFS, and EDN concentrations were higher in patients with active EoE than in controls or patients with EoE in remission (inactive). When grouping patients based on esophageal eosinophilia distribution, EDN mirrored PEC, and EREFS. Patients with exclusive distal eosinophilia had lower EDN concentrations than those with eosinophilia in >1 level of the esophagus (23.8 ± 46.1 mcg/mL vs. 171.3 ± 205.8 mcg/mL respectively, p < 0.001). EDN values were more consistent with EREFS in cases of discrepancies between endoscopic findings and pathology (p < 0.001). CONCLUSION: EDN measured in esophageal brushing samples reflects disease activity objectively and accurately. It also offers significant value in cases of exclusive distal esophageal eosinophilia and when discrepancies exist between endoscopy and histology.

Serum microRNA-223 as a potential biomarker for allergic rhinitis and its correlation to eosinophil-derived neurotoxin.

Allergic rhinitis (AR) is a global health problem. It is an inflammatory condition defined by a malfunction of the immune system's regulatory mechanism. MicroRNA-223 (miRNA-223) has been linked to the modulation of AR in the last few years. The goal of this study was to determine whether miR-223 can be utilized as a potential biomarker for diagnosis of AR, and whether it correlates with the total nasal symptom score (TNSS) along with serum interleukin-17 (IL-17), interleukin-4 levels (IL-4) and eosinophil-derived neurotoxin (EDN). This study included 76 adult participants, consisted of 38 AR patients and 38 apparently healthy controls. Serum levels of miR-223 were assayed using real-time PCR. The levels of EDN, IL-17 and IL-4 in the serum were determined using an enzyme-linked immunosorbent assay. The optimal cutoff value for the analyzed factors to diagnose AR was determined using a receiver operating characteristic curve analysis (ROC). The demographic features (age and gender) of the two study groups were matched. Patients with pollen-induced AR had significantly higher levels of miR-223 in their serum compared to the controls (median = 3.82; median = 1.03, respectively, p < 0.001). In AR cases, a significant positive association was observed between miR-223 expression level and TNSS (r = 0.492, p = 0.002), EDN serum level (r = 0.427, p = 0.008), IL-4 serum level (r = 0.341, p = 0.036) and IL-17 serum level (r = 0.324, p = 0.047). MiR-223, at a cutoff value of 1.18, had a sensitivity and specificity of 94.9 % and 92.5%, respectively. In conclusion, miR-223 expression is significantly greater in blood of AR patients. There is a significant association between miR-223 and clinical severity of AR, each of IL-17 and IL-4 as well as EDN. Therefore, miR-223 may be employed as an effective biomarker for AR diagnosis.

Eosinophil-derived neurotoxin levels in early childhood and association with preschool asthma - A prospective observational study.

INTRODUCTION: Eosinophil-derived neurotoxin (EDN) is related to childhood asthma, while normal values are lacking. We aimed to document serum EDN levels at 1 and 3 years in general and in non-atopic children, and explore if EDN levels differed by sex or were associated with preschool asthma at 3 years. METHODS: From the PreventADALL birth cohort, we included 1233 children with EDN analysed using ImmunoCAP at 1 and/or 3 years. Non-atopic children had no history of wheeze, asthma, allergic sensitization or atopic dermatitis. Preschool asthma was defined as having ≥3 episodes of bronchial obstruction between 2 and 3 years, plus doctor diagnosed asthma and/or asthma medication use by 3 years. The upper limit of normal (ULN) of EDN was defined as the 95th percentile. With Youden Index we calculated EDN cut-off levels for risk of preschool asthma. RESULTS: The overall median (ULN) EDN levels were 27.4 (121) µg/L at 1 year (n = 787), and 20.1 (87.8) µg/L at 3 years (n = 857). Non-atopic children had EDN levels of 24.0 (107) µg/L at 1 year (n = 147), and 17.3 (84.6) µg/L at 3 years (n = 173). EDN levels were higher in boys compared to girls; 32.0 (133) versus 24.5 (97.0) µg/L at 1 year, and 20.9 (96.3) versus 19.0 (72.4) µg/L at 3 years. Preschool asthma was observed in 109/892 (12.2%) children. Higher EDN levels at 1 (>26.7 µg/L) and 3 (≥20.5 µg/L) years were associated with preschool asthma; adjusted OR (95% CI) 2.20 (1.09, 4.41) and 4.68 (2.29, 9.55), respectively. CONCLUSION AND CLINICAL RELEVANCE: We report EDN values in early childhood, demonstrating higher levels at 1 compared to 3 years and in boys compared to girls at both ages. Higher EDN levels at both ages were associated with preschool asthma. However, EDN cut-off levels for preschool asthma were overall lower than the ULN of non-atopic children, limiting translation into clinical practice.

Antiviral effect of high-pressure nasal stimulation.

OBJECTIVE: In a previous study, we reported an increase of nasal nerve growth factor (NGF) in patients treated with high-pressure administration of sterile saline isotonic solution (HPpSIS). Herein we characterized the nasal mucosa in terms of innate immune response and cytokine signature, including antiviral properties. Potential NGF and antiviral benefits of HPpSIS were also discussed. PATIENTS AND METHODS: Twenty (20) patients (11 males, 9 females; age range 30-75 years old) underwent HPpSIS and nasal samples were collected before and after treatment. Nasal scraping was used for morphological (smears and Quick May-Grunwald Giemsa staining, MGG), biochemical (Histamine, Serotonin; ELISA) and molecular (messenger RNA, mRNA) analyses. Amplification of transcripts specific for Toll-like receptor (TLR) 3 (TLR3), TLR7, TLR9, Interleukin-(IL) 18 (IL18), IL13, IL12, eosinophil-derived neurotoxin (EDN), Eosinophil Cationic Protein (ECP), γ Interferon (γIFN), tryptase and serotonin was performed using the 2-step real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR). Clinical and laboratory data were analyzed and compared. RESULTS: The clinical evaluation showed a protective effect of our therapy. Smears showed the presence of leucocytes, eosinophils (EOs) and mast cells (MCs), and increased immunoreactivity for ECP/RNase3 and EDN after HPpSIS. ELISA showed increased levels of Serotonin and EDN associated with unchanged levels of substance P(SP) and histamine. Increased eosinophil-derived neurotoxin eosinophil-derived neurotoxin (EDN) levels were confirmed by in situ fluorescent analysis. HPpSIS induced the upregulation of TLR3, TLR7 and TLR9 transcripts, while no changes were observed for Intercellular Adhesion Molecule 1 (ICAM1), IL18, Interleukin-15 (IL15) and IL12 transcripts nor for Interleukin-6 (IL6) and IL13. No changes were also observed for γIFN and EDN/RNase2 transcripts, while ECP/RNase3 transcripts were significantly upregulated after HPpSIS. Finally, tryptase transcripts were unchanged while serotonin transcripts were significantly increased after HPpSIS. CONCLUSIONS: The clinical and biomolecular changes observed at the nasal mucosa due to HpSS treatment suggest the activation of an innate surveillance, by means of TLR transcription, and a possible anti-viral response due to EDN upregulation. It remains to be verified if NGF, known to be released locally upon HpSIS treatment, might in part be responsible for this local activation.

Association of EDN levels in patients with asthma and correlation with FEV1%: A meta-analysis.

Background: Eosinophil-derived neurotoxin (EDN), an eosinophil degranulation product, is a good biomarker for eosinophilic inflammation of the airway. Several articles have shown that EDN levels are higher in patients with asthma than in controls, and EDN levels are correlated with the percentage of predicted forced expiratory volume in the first second (FEV1%) in patients with asthma. Their results were inconclusive. Methods: A comprehensive meta-analysis was performed to assess EDN levels between patients with asthma and controls, and the correlations between EDN and FEV1% in the patients with asthma. Fourteen relevant articles were identified from electronic data bases. Pooled standardized mean difference (SMD) with a 95% confidence interval (CI) for the difference of EDN levels between the patients with asthma and controls, and pooled coefficient (r) values with 95% CI for the correlations between EDN and FEV1%, respectively, were calculated. Results: A total of 14 articles were selected. Among the included reports, six articles related to the difference and eight essays on the correlation. Pooled effect size showed that EDN levels were higher in patients with asthma than in controls (SMD 2.85 [95% CI, 1.92-3.78]). Furthermore, the pooled effect size showed that EDN levels were negatively correlated with FEV1% in patients with asthma (r -0.21 [95% CI, -0.28 to -0.14]). Conclusion: EDN levels increased in the patients with asthma compared with in the controls. They were correlated with FEV1% in the patients with asthma, which indicated that EDN could be a reliable marker to monitor asthma's therapeutic effects.

Olfactory cleft mucus eosinophil-derived neurotoxin better reflects olfactory loss than blood eosinophil counts in patients with chronic rhinosinusitis.

BACKGROUND: Eosinophils are associated with olfactory dysfunction in chronic rhinosinusitis (CRS) and eosinophil-derived neurotoxin (EDN) is a sensitive marker of intense eosinophil activation. This study aimed to analyze olfactory cleft mucus and olfactory mucosa EDN levels and their association with olfactory dysfunction in CRS. METHODS: We prospectively recruited 150 patients with CRS electing endoscopic sinus surgery and 25 healthy controls. Both superior turbinate biopsy specimens and olfactory cleft mucus were collected to analyze EDN levels. Sniffin' Sticks test scores, olfactory cleft computed tomography (CT) scores, and olfactory cleft endoscopy scale (OCES) were obtained. Multivariable logistic regression analysis was applied to analyze the predictability of EDN levels for olfactory dysfunction in CRS. RESULTS: Chronic rhinosinusitis with olfactory dysfunction presented significantly higher olfactory mucosa (p = 0.016) and olfactory cleft mucus (p < 0.001) EDN levels than CRS without olfactory dysfunction. Mucus EDN levels were positively correlated with blood eosinophils (r = 0.625, p = 0.002), olfactory cleft CT scores (r = 0.738, p < 0.001), and OCES (r = 0.605, p = 0.004) in CRS. Furthermore, mucus EDN levels were significantly negatively correlated with threshold, discrimination, and identification (TDI) (r = -0.688), olfactory threshold (r = -0.606), olfactory discrimination (r = -0.608), and olfactory identification (r = -0.697) scores. After adjusting for patient demographics and comorbidities, mucus EDN levels were significantly associated with olfactory dysfunction in CRS (odds ratio = 2.162; p = 0.027). Mucus EDN levels showed a significantly better performance for predicting olfactory dysfunction than blood eosinophil counts (area under the curve, 0.873 vs. 0.764, p = 0.024). CONCLUSION: Olfactory cleft mucus EDN level may be a better biomarker for predicting olfactory dysfunction in CRS than blood eosinophil counts.

The Role of Eosinophil-Derived Neurotoxin and Vascular Endothelial Growth Factor in the Pathogenesis of Eosinophilic Asthma.

Asthma is a chronic complex pulmonary disease characterized by airway inflammation, remodeling, and hyperresponsiveness. Vascular endothelial growth factor (VEGF) and eosinophil-derived neurotoxin (EDN) are two significant mediators involved in the pathophysiology of asthma. In asthma, VEGF and EDN levels are elevated and correlate with disease severity and airway hyperresponsiveness. Diversity in VEGF polymorphisms results in the variability of responses to glucocorticosteroids and leukotriene antagonist treatment. Targeting VEGF and eosinophils is a promising therapeutic approach for asthma. We identified lichochalcone A, bevacizumab, azithromycin (AZT), vitamin D, diosmetin, epigallocatechin gallate, IGFBP-3, Neovastat (AE-941), endostatin, PEDF, and melatonin as putative add-on drugs in asthma with anti-VEGF properties. Further studies and clinical trials are needed to evaluate the efficacy of those drugs. AZT reduces the exacerbation rate and may be considered in adults with persistent symptomatic asthma. However, the long-term effects of AZT on community microbial resistance require further investigation. Vitamin D supplementation may enhance corticosteroid responsiveness. Herein, anti-eosinophil drugs are reviewed. Among them are, e.g., anti-IL-5 (mepolizumab, reslizumab, and benralizumab), anti-IL-13 (lebrikizumab and tralokinumab), anti-IL-4 and anti-IL-13 (dupilumab), and anti-IgE (omalizumab) drugs. EDN over peripheral blood eosinophil count is recommended to monitor the asthma control status and to assess the efficacy of anti-IL-5 therapy in asthma.

Fecal Biomarkers of Neutrophil and Eosinophil Origin Reflect the Response to Biological Therapy and Corticosteroids in Patients With Inflammatory Bowel Disease.

INTRODUCTION: Fecal calprotectin (FC) is a noninvasive tool for examining response to biologics in inflammatory bowel disease (IBD), but its performance in relation to other novel fecal markers of various cellular origins is unknown. METHODS: We performed a prospective multicenter cohort study and included patients with active IBD who provided a fecal sample at initiation of biological therapy. Levels of FC, myeloperoxidase (MPO), human neutrophil lipocalin (HNL), and eosinophil-derived neurotoxin (EDN) were analyzed and related to clinical remission status at 3 months. Changes in levels of markers at 3 months were calculated, and the impact of concomitant use of corticosteroids at baseline was estimated. RESULTS: In patients achieving clinical remission (n = 27), a decrease in levels of FC ( P = 0.005), MPO ( P < 0.001), HNL ( P < 0.001), and EDN ( P < 0.001) was observed, whereas no significant decrease was seen in patients not achieving remission (n = 39). There was a significant difference in the change in the level of MPO ( P = 0.01) and HNL ( P = 0.02) between patients achieving clinical remission and those who did not, but changes in FC and EDN could not differentiate between these groups. Patients with concomitant systemic corticosteroids at inclusion had lower levels of HNL ( P = 0.01) and EDN ( P < 0.001) at baseline, compared with patients without corticosteroids. DISCUSSION: Fecal MPO, HNL, and EDN are all promising biomarkers for assessing the treatment outcome of biologics in patients with IBD. Fecal levels of EDN and HNL are significantly affected by corticosteroids indicating a greater sensitivity to the effects of corticosteroids compared with levels of FC and MPO.

Eosinophil Granule Proteins Involvement in Acute Appendicitis-An Allergic Disease?

Several pieces of evidence point to an allergic component as a trigger of acute appendicitis. As the Th2 immune response is characterized by eosinophil mobilization to the target organ and release of their cationic granule proteins, it is reasonable to investigate if the degranulation of eosinophils could be associated with the local injury. The primary aim of this study is to evaluate the participation of eosinophils granules proteins in acute appendicitis, both at local and systemic levels and the secondary aim is to evaluate the diagnostic accuracy of eosinophils granules proteins for the detection of acute appendicitis, as well as for distinguishing between complicated and uncomplicated acute appendicitis. Eosinophil-derived neurotoxin (EDN), eosinophil cationic protein (ECP) and eosinophil peroxidase (EP) are the most well-known eosinophil granule proteins. From August 2021 to April 2022, we present a prospective single-center study to evaluate the EDN, ECP, and EP concentrations simultaneously in appendicular lavage fluid (ALF) and the serum of 22 patients with acute phlegmonous appendicitis (APA), 24 with acute gangrenous appendicitis (AGA), and 14 normal controls. Concerning EDN, no differences were found between groups. ECP concentrations in ALF and serum were significantly higher in the histologically confirmed acute appendicitis compared to the control groups (p < 0.0001 and p < 0.0001, respectively). In ALF, no differences were found between ECP levels in APA: 38.85 ng/mL (IQR 26.50-51.77) and AGA 51.55 ng/mL (IQR 39.55-70.09) groups (p = 0.176). In the serum, no difference was found between ECP levels at APA: 39 ng/mL (IQR 21.30-56.90) and AGA: 51.30 ng/mL (IQR 20.25-62.59) (p = 0.100). For EP, the concentrations in ALF (p < 0.001) and serum (p < 0.001) were both higher in acute appendicitis compared to the control. In ALF, no difference was found between APA: 240.28 ng/mL (IQR 191.2-341.3) and AGA: 302.5 (IQR 227.7-535.85) (p = 0.236). In the serum, no differences were found between APA: 158.4 ng/mL (IQR 111.09-222.1) and AGA: 235.27 (IQR 192.33-262.51) (p = 0.179). Globally, the ALF concentrations were higher than serum concentrations, reflecting an intense inflammatory local reaction in AA. The optimal ECP cut-off for discriminating between acute appendicitis and the controls was >11.41 ng/mL, with a sensitivity of 93.5%, but with a specificity for identifying appendicitis of 21.4%, good discriminative power (AUC = 0.880). For EP, the optimal cut-off was >93.20 ng/mL, with a sensitivity of 87%, but with a specificity of 14.3% (AUC = 0.901), excellent discriminative power. For the diagnosis of perforated AA, the discriminative power of ECP and EP serum concentrations are weak (AUC = 0.562 and AUC = 0.664, respectively). Concerning the presence of peritonitis, the discriminative power of ECP and EP serum concentrations is acceptable, respectively: AUC = 0.724 and AUC = 0.735. Serum levels of EDN (p = 0.119), ECP (p = 0.586) and EP (p = 0.08) in complicated appendicitis were similar to uncomplicated appendicitis. Serum concentrations of ECP and EP can be added to decision-making AA diagnosis. A Th2-type immune response is present in AA. These data bring forward the role of an allergic reaction in the pathogenesis of acute appendicitis.

Biomarkers for predicting type 2-high and uncontrolled asthma in real-world practice.

BACKGROUND: Blood eosinophil count (BEC), immunoglobulin (Ig) E, and fractional exhaled nitric oxide (FeNO) are key clinical indicators for identifying type 2 (T2) asthma. OBJECTIVE: To provide optimal cutoff points of T2 markers for assessing T2-high or uncontrolled asthma in real-world practice. METHODS: Various clinical and laboratory parameters were analyzed according to the result of T2 markers (BEC, serum-free IgE, and FeNO) in adults with asthma who had maintained antiasthmatic medications. The cutoff levels for representing uncontrolled asthma were determined using receiver operating characteristic analysis. Blood levels of periostin and eosinophil-derived neurotoxin were measured by enzyme-linked immunosorbent assay. Activation markers of circulating eosinophils (Siglec8+) and neutrophils (CD66+) were analyzed by flow cytometry. RESULTS: Of 133 patients with asthma, 23 (17.3%) had 3 T2 markers (BEC ≥ 300 cells/µL, serum-free IgE ≥ 120 ng/mL, and FeNO ≥ 25 parts per billion) and significantly higher levels of sputum eosinophils, blood eosinophil-derived neurotoxin, and Siglec8+ eosinophils but lower 1-second forced expiratory volume percentage, in addition to a higher rate of uncontrolled status (P < .05 for all). Furthermore, patients with uncontrolled asthma had significantly higher levels of FeNO and BEC with lower 1-second forced expiratory volume percentage (P < .05 for all). The optimal cutoff values for predicting uncontrolled asthma were found to be 22 parts per billion of FeNO levels, 161.4 cells/L of BECs, and 85.9 ng/mL of serum-free IgE levels. CONCLUSION: We suggest the optimal cutoff values of BEC, IgE, and FeNO for classifying T2-high or uncontrolled asthma, which could be applied as candidate biomarkers for targeting patients with asthma who require T2 biologics.

Urine eosinophil-derived neurotoxin: A potential marker of activity in select eosinophilic disorders.

BACKGROUND: Biomarkers of eosinophilic disease activity, especially in the context of novel therapies that reduce blood eosinophil counts, are an unmet need. Absolute eosinophil count (AEC) does not accurately reflect tissue eosinophilia or eosinophil activation. Therefore, the aims of this study were to compare the reliability of plasma and urine eosinophil major basic protein 1, eosinophil cationic protein, eosinophil-derived neurotoxin (EDN), and eosinophil peroxidase measurement and to evaluate the usefulness of eosinophil granule protein (EGP) measurement for the assessment of disease activity in patients with eosinophil-associated diseases treated with mepolizumab, benralizumab, or dexpramipexole. METHODS: Eosinophil granule protein concentrations were measured in serum, plasma, and urine from healthy volunteers and patients with hypereosinophilic syndrome (HES), eosinophilic granulomatosis with polyangiitis (EGPA), and eosinophilic asthma using a multiplex assay. RESULTS: Urine EGP concentrations remained stable, whereas serum and plasma EGP concentrations increased significantly with delayed processing. Plasma (p) EDN, but not urine (u) EDN, concentration correlated with AEC and negatively correlated with prednisone dose. Both pEDN and uEDN decreased significantly following treatment of HES patients with benralizumab and EGPA patients with mepolizumab. uEDN appeared to increase with clinical relapse in both patient groups. CONCLUSIONS: Measurement of EGP in urine is noninvasive and unaffected by cellular lysis. Although plasma and urine EDN concentrations showed a similar pattern following benralizumab and mepolizumab treatment, the lack of correlation between AEC or prednisone dose and uEDN concentrations suggests that measurement of uEDN may provide a potential biomarker of disease activity in patients with HES and EGPA.

Clinical Potential of Eosinophil-Derived Neurotoxin in Asthma Management.

The assessment and management of patients with asthma is challenging because of the complexity of the underlying inflammatory mechanisms and heterogeneity of their clinical presentation. Optimizing disease management requires therapy individualization that should rely on reliable biomarkers to unravel the phenotypes and endotypes of asthma. The secretory activity and turnover of eosinophils, as assessed by measuring eosinophil-derived proteins, may provide an accurate and complementary tool that mirrors the eosinophil activation status. Emerging evidence suggests that eosinophil-derived neurotoxin has considerable potential as a precision medicine biomarker. In this review, we explore the suitability of eosinophil-derived neurotoxin as a biomarker in asthma management, with particular emphasis on its clinical significance in the management of both pediatric and adult populations.

Serum Levels of Vascular Endothelial Growth Factor, Platelet Activating Factor and Eosinophil-Derived Neurotoxin in Chronic Spontaneous Urticaria-A Pilot Study in Adult Patients.

Chronic spontaneous urticaria (CSU) is a skin disease characterized by the presence of wheals, angioedema, or both for at least 6 weeks. Although, CSU is often regarded as autoimmune in nature, its etiology is not fully explained and interactions between various small molecules are still taken under account. The aim of this research was to investigate the mean serum concentration of vascular endothelial growth factor (VEGF), platelet activating factor (PAF), and eosinophil-derived neurotoxin (EDN) in relation to the disease activity and pruritus intensity in adult patients with CSU. Fifteen patients with CSU and 15 healthy subjects participated in this pilot study. Blood samples were taken to examine the mean serum levels of VEGF, PAF, and EDN by the enzyme-linked immunosorbent assay test (ELISA). The Urticaria Activity Score (UAS7) and The Visual Analogue Scale (VAS) were used to assess the disease activity and the pruritus intensity, respectively. Obtained results revealed that VEGF, PAF, and EDN concentrations were higher in patients with CSU compared with those of the control group, but only for VEGF it was statistically significant (p = 0.008). However, levels of all investigated cytokines were not significantly correlated neither with the disease activity nor with the pruritus intensity. Our results showed higher serum levels of VEGF, PAF, and EDN among CSU patients which may highlight a functional role of these cytokines in the disease's pathogenesis. In contrast, VEGF, PAF, or EDN might not be useful to reflect the severity of symptoms.

Identification of novel genes influencing eosinophil-specific protein levels in asthma families.

BACKGROUND: Eosinophils play a key role in the asthma allergic response by releasing cytotoxic molecules such as eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN) that generate epithelium damages. OBJECTIVE: We sought to identify genetic variants influencing ECP and EDN levels in asthma-ascertained families. METHODS: We performed univariate and bivariate genome-wide association analyses of ECP and EDN levels in 1018 subjects from the EGEA study with follow-up in 153 subjects from the Saguenay-Lac-Saint-Jean study and combined the results of these 2 studies through meta-analysis. We then conducted Bayesian statistical fine mapping together with quantitative trait locus and functional annotation analyses to identify the most likely functional genetic variants and candidate genes. RESULTS: We identified 5 genome-wide significant loci (P &lt; 5 × 10^-8) including 7 distinct signals associated with ECP and/or EDN levels. The genes targeted by our fine mapping and functional search include RNASE2 and RNASE3 (14q11), which encode EDN and ECP, respectively, and 4 other genes that regulate ECP and EDN levels. These 4 genes were JAK1 (1p31), a transcription factor that plays a key role in the immune response and acts as a potential therapeutic target for eosinophilic asthma; ARHGAP25 (2p13), which is involved in leukocyte recruitment to inflammatory sites; NDUFA4 (7p21), which encodes a component of the mitochondrial respiratory chain and is involved in cellular response to stress; and CTSL (9q22), which is involved in immune response, extracellular remodeling, and allergic inflammation. CONCLUSION: Analysis of specific phenotypes produced by eosinophils allows the identification of genes that play a major role in allergic response and inflammation, and offers potential therapeutic targets for asthma.

Single-cell RNA Sequencing Identified Novel Nr4a1+ Ear2+ Anti-Inflammatory Macrophage Phenotype under Myeloid-TLR4 Dependent Regulation in Anti-Glomerular Basement Membrane (GBM) Crescentic Glomerulonephritis (cGN).

Previously, this study demonstrates the critical role of myeloid specific TLR4 in macrophage-mediated progressive renal injury in anti-glomerular basement membrane (anti-GBM) crescentic glomerulonephritis (cGN); however, the underlying mechanism remains largely unknown. In this study, single-cell RNA sequencing (scRNA-seq), pseudotime trajectories reconstruction, and motif enrichment analysis are used, and macrophage diversity in anti-GBM cGN under tight regulation of myeloid-TLR4 is uncovered. Most significantly, a myeloid-TLR4 deletion-induced novel reparative macrophage phenotype (Nr4a1+ Ear2+) with significant upregulated anti-inflammatory and tissue repair-related signaling is discovered, thereby suppressing the M1 proinflammatory responses in anti-GBM cGN. This is further demonstrated in vitro that deletion of TLR4 from bone marrow-derived macrophages (BMDMs) induces the Nr4a1/Ear2-expressing anti-inflammatory macrophages while blocking LPS-stimulated M1 proinflammatory responses. Mechanistically, activation of the Nr4a1/Ear2-axis is recognized as a key mechanism through which deletion of myeloid-TLR4 promotes the anti-inflammatory macrophage differentiation in vivo and in vitro. This is confirmed by specifically silencing macrophage Nr4a1 or Ear2 to reverse the anti-inflammatory effects on TLR4 deficient BMDMs upon LPS stimulation. In conclusion, the findings decode a previously unidentified role for a myeloid-TLR4 dependent Nr4a1/Ear2 negative feedback mechanism in macrophage-mediated progressive renal injury, implying that activation of Nr4a1-Ear2 axis can be a novel and effective immunotherapy for anti-GBM cGN.

RNASE2 Mediates Age-Associated B Cell Expansion Through Monocyte Derived IL-10 in Patients With Systemic Lupus Erythematosus.

Systemic lupus erythematosus (SLE) is characterized by the production of pathogenic autoantibodies. Ribonuclease A family member 2 (RNase2) is known to have antiviral activity and immunomodulatory function. Although RNASE2 level has been reported to be elevated in SLE patients based on mRNA microarray detection, its pathologic mechanism remains unclear. Here, we confirmed that RNASE2 was highly expressed in PBMCs from SLE patients and associated with the proportion of CD11c+T-bet+ B cells, a class of autoreactive B cells also known as age-associated B cells (ABCs). We showed that reduction of RNASE2 expression by small interfering RNA led to the decrease of ABCs in vitro, accompanied by total IgG and IL-10 reduction. In addition, we demonstrated that both RNASE2 and IL-10 in peripheral blood of lupus patients were mainly derived from monocytes. RNASE2 silencing in monocytes down-regulated IL-10 production and consequently reduced ABCs numbers in monocyte-B cell co-cultures, which could be restored by the addition of recombinant IL-10. Based on above findings, we concluded that RNASE2 might induce the production of ABCs via IL-10 secreted from monocytes, thus contributing to the pathogenesis of SLE.

Eosinophil-derived neurotoxin: An asthma exacerbation biomarker in children.

Background: Asthma is a heterogeneous disease, characterized by chronic airway inflammation. Asthma exacerbations (AE) are episodes characterized by a progressive increase in symptoms of shortness of breath, cough, wheezing, or chest tightness with a decrease in lung function. There have been previous studies that examined the role of eosinophil-derived neurotoxin (EDN) in asthma, but there have been no studies of the role of EDN in children experiencing AE. Objective: In this study, we aimed to examine the association of EDN with lung function and prognosis in children admitted for severe AE. Methods: We enrolled 82 children who were admitted for severe AE at two different university hospitals in South Korea between January 2018 and December 2019. Blood tests, including white blood cell count, myeloperoxidase (MPO), total eosinophil count, EDN, C-reactive protein (CRP) level, and interleukin (IL) 4, IL-5, IL-10 values, and lung function were measured on admission and at discharge in each patient. Results: We observed significant decreases in the levels of MPO, EDN, CRP, and IL-4, with significant improvement in lung function after treatment. We then classified the subjects into two groups of different clinical phenotypes: eosinophilic asthma exacerbation (EAE) group and non-EAE group. EDN levels were higher and lung functions were lower in the EAE group. Also, we found that the EDN level was a significant biomarker useful for predicting the number of days for hospital stay. Conclusion: We found that EDN can act as a biomarker that reflects lung function, and that EDN could act as a prognostic biomarker, which demonstrated the complex role of EDN in children experiencing AE.