Evidence for eosinophil and IL-17 mediated inflammation in allergic rhinitis

Up-regulation of systemic and local BDNF in non-allergic Nasal Polyps in China

Objective

Although the role of brain-derived neurotrophic factor (BDNF) in allergic rhinitis and/or nasal polyps (NPs) development has been studied, the contribution of BDNF in non-allergic NPs has not been evaluated yet. This study was to investigate the possible role of BDNF in non-allergic NPs pathogenesis.

Methods

The study was carried out at The Second Hospital of Shandong University from December 2020 to November 2021. The non-allergic NPs patients (n=26) and the control group (n=22) were included. Lund-Mackay CT scores, nasal endoscopy scores, and pulmonary function testing were evaluated before surgery. Tissue and serum levels of BDNF, eosinophil cationic protein (ECP), and cytokeratins 5 (CK5) were assessed between different groups.

Result

The BDNF level in serum and tissue, CK5 count, and eosinophil infiltration in tissue were higher in non-allergic NPs. The eosinophils infiltration, ECP mRNA expression level, as well as BDNF mRNA level were increased in the BDNFhigh subgroup compared with BDNFlow subgroup. Significantly negative correlations between BDNF count and the situation of airway obstruction were found in non-allergic NPs.

Conclusion

BDNF may have both local and systemic effects in non-allergic NPs pathogenesis. BDNF may be a possible therapeutic target or an indicator for eosinophilic NPs management.

TGF-β, IL-1β, IL-6 levels and TGF-β/Smad pathway reactivity regulate the link between allergic diseases, cancer risk, and metabolic dysregulations

The risk of cancer is higher in patients with asthma compared to those with allergic rhinitis for many types of cancer, except for certain cancers where a contrasting pattern is observed. This study offers a potential explanation for these observations, proposing that the premalignant levels of circulating transforming growth factor-β (TGF-β), IL-1β, and IL-6 as well as the reactivity of the TGF-β/Smad signaling pathway at the specific cancer site, are crucial factors contributing to the observed disparities. Circulating TGF-β, IL- β and IL-6 levels also help clarify why asthma is positively associated with obesity, Type 2 diabetes, hypertension, and insulin resistance, whereas allergic rhinitis is negatively linked to these conditions. Furthermore, TGF-β/Smad pathway reactivity explains the dual impact of obesity, increasing the risk of certain types of cancer while offering protection against other types of cancer. It is suggested that the association of asthma with cancer and metabolic dysregulations is primarily linked to the subtype of neutrophilic asthma. A binary classification of TGF-β activity as either high (in the presence of IL-1β and IL-6) or low (in the presence or absence of IL-1β and IL-6) is proposed to differentiate between allergy patients prone to cancer and metabolic dysregulations and those less prone. Glycolysis and oxidative phosphorylation, the two major metabolic pathways utilized by cells for energy exploitation, potentially underlie this dichotomous classification by reprogramming metabolic pathways in immune cells.

Bordetella spp. block eosinophil recruitment to suppress the generation of early mucosal protection

Bordetella spp. are respiratory pathogens equipped with immune evasion mechanisms. We previously characterized a Bordetella bronchiseptica mutant (RB50ΔbtrS) that fails to suppress host responses, leading to rapid clearance and long-lasting immunity against reinfection. This work revealed eosinophils as an exclusive requirement for RB50ΔbtrS clearance. We also show that RB50ΔbtrS promotes eosinophil-mediated B/T cell recruitment and inducible bronchus-associated lymphoid tissue (iBALT) formation, with eosinophils being present throughout iBALT for Th17 and immunoglobulin A (IgA) responses. Finally, we provide evidence that XCL1 is critical for iBALT formation but not maintenance, proposing a novel role for eosinophils as facilitators of adaptive immunity against B. bronchiseptica. RB50ΔbtrS being incapable of suppressing eosinophil effector functions illuminates active, bacterial targeting of eosinophils to achieve successful persistence and reinfection. Overall, our discoveries contribute to understanding cellular mechanisms for use in future vaccines and therapies against Bordetella spp. and extension to other mucosal pathogens.

RORα overexpression reduced interleukin-33 expression and prevented mast cell degranulation and inflammation by inducing autophagy in allergic rhinitis

BACKGROUND

Retinoid acid receptor related orphan receptor α (RORα) is a nuclear receptor that along with other bioactive factors regulates cell proliferation, differentiation, and immunomodulation in vivo.

AIMS

The objective of this study was to explore the function and mechanism of RORα in allergic rhinitis (AR).

MATERIALS AND METHODS

Derp1 was used to construct an AR cell model in HNEpC cells, and RORα was overexpressed or silenced in the AR HNEpC cells. Next, LAD2 cells were co-cultured with the Derp1-treated HNEpC cells. Additionally, an AR mouse model was established using by OVA, and a RORα Adenovirus was delivered by nebulizing. Pathological tissue structures were evaluated by hematoxylin-eosin staining, and the levels of RORα, interleukin-33 (IL-33), and other proteins were analyzed immunohistochemistry, western blotting, and immunofluorescence staining. IL-33, IL-4, IL-5, and IL-13 levels were detected using enzyme-linked immunosorbent assay kits and cell migration was assessed by Transwell assays.

RESULTS

Our data showed that RORα was downregulated in the nasal mucosa tissues of AR patients. Derp1 treatment could cause a downregulation of RORα, upregulation of IL-33, the induction of NLRP3 inflammasomes, and cell migration in HNEpC cells. Furthermore, RORα overexpression dramatically attenuated IL-33 levels, NLRP3 inflammasome activity, and the migration of AR HNEpC cells induced with Derp1. Moreover, RORα in AR HNEpC cells could prevent mast cell (MC) degranulation and inflammation by accelerating autophagy, RORα overexpression inhibited MC degranulation and NLRP3-induced inflammation in the AR model mice. RORα overexpression reduced IL-33 expression in nasal epithelial cells, and also suppressed MC degranulation and inflammation by promoting autophagy.

CONCLUSION

RORα inhibits NLRP3 inflammasome in HNEpC, and attenuated mast cells degranulation and inflammation through autophagy in AR.

Allergic rhinitis associated with the degree of pulmonary involvement due to COVID-19 in patients from a peruvian general hospital

OBJECTIVES.

To evaluate the association between allergic rhinitis and the degree of pulmonary involvement in patients with COVID-19 and to determine the frequencies of the main variables.

MATERIALS AND METHODS.

An observational, cross-sectional and analytical study was carried out by reviewing the medical records of patients diagnosed with COVID-19 from the Cayetano Heredia National Hospital between 2020 and 2021. We obtained information regarding the history of allergic rhinitis; pulmonary involvement was assessed by non-contrast tomography results using the chest computed tomography (CT) score. Data regarding sociodemographic and clinical variables was also obtained. Both crude (PR) and adjusted (aPR) prevalence ratios with their respective 95% confidence intervals (CI) were estimated. We also used a generalized linear Poisson family model with log link function and robust variances.

RESULTS.

We evaluated 434 patients, who were mostly male, older than 60 years and had no relevant medical history. Of these, 56.2% had a history of allergic rhinitis and 43.1% had moderate to severe pulmonary involvement. The adjusted regression model showed that the history of allergic rhinitis reduced the severity of COVID-19 according to the pulmonary involvement assessed by the CT score (aPR: 0.70; 95%CI: 0.56-0.88; p=0.002).

CONCLUSIONS.

The history of allergic rhinitis resulted in a 30.0% decrease in COVID-19 severity according to the CT score in hospitalized patients.

Efficacy and Safety of Diethylcarbamazine in Treatment of Allergic Rhinitis: A Double Blind Randomised Controlled Trial

There are many evidences showing diethylcarbamazine as a potential drug for the treatment of allergic rhinitis. This study evaluated the effectiveness of diethylcarbamazine in the treatment of allergic rhinitis and compared it with montelukast and levocetirizine. This parallel double-blind randomized clinical trial was done in allergic rhinitis patients. Seven hundred and twelve participants who met the inclusion criteria and provided informed written consent were randomized and divided into 2 equal groups. Diethylcarbamazine 300 mg/day orally in divided doses was given to group A, and montelukast 10 mg and levocetirizine 5 mg/day orally at night for 21 days was given to group B. Primary outcomes were the change in symptoms, absolute eosinophil count, serum total IgE, phadiatop and response in skin prick from baseline to 21 days and 3 months after treatment. Secondary outcome was to compare it with montelukast and levocetirizine. The mean (SD) age of the patients was 33 (10.6) years, with 374 (52.5%) males and 338 (47.5%) females. There was statistically significant improvement in all the parameters in both groups. Improvement was better with diethylcarbamazine compared to montelukast and levocetirizine and the effects were sustained for 3 months in diethylcarbamazine group. The findings suggest that diethylcarbamazine is effective in the treatment of allergic rhinitis. It gives better control and is cost-effective than montelukast and levocetirizine. Trial Registration: https://www.ctri.nic.in Identifier: CTRI/2020/03/024145 registered on 20-03-2020.

Scraping nasal cytology in the diagnostics of rhinitis and the comorbidities

Nasal scraping cytology is a non-invasive tool used in the diagnostics of allergic and non-allergic rhinitis. The study aimed to analyze to what extent the cytological picture of the nasal mucosa coincides with the diagnosis of a given disease, taking into account the content of eosinophils. Retrospective analysis of the cytograms performed in 842 patients was carried out in relation to the disease entities and the content of eosinophils. Significant relationship between the Epith:Infl ratio and the four groups of diseases (Chi² = 9.6488; p = .014) was confirmed. The more intensive inflammation was found, the higher percentage of patients had manifested the increased level of eosinophils (> 1% in the inflammatory cells). The value of 20% of eosinophils in all counted cells corresponds to around 45% of eosinophils in the inflammatory cells in patients with the evident inflammatory picture. Allergic rhinitis presents a different cytological picture regarding the eosinophilic reaction against the background of the inflammation process: the higher degree of inflammation observed, the lower amount of eosinophils detected, with the exception of allergic rhinitis provoked by pollen allergens.

[Diagnostic value of a novel test paper detection of ECP in nasal secretion for allergic rhinitis]

Objective:To explore the diagnostic value of a novel test paper, which detect eosinophil cationic protein（ECP） of nasal secretion in allergic rhinitis（AR）. Methods:Nasal secretion and serum samples from 107 patients with allergic rhinitis（AR group） and 40 healthy volunteers（control group） were selected. The nasal symptoms were also evaluated in AR group. The degree of ECP coloration was evaluated by nasal secretion eosinophil cationic protein-myeloperoxid（ECP-MPO） test paper, and the concentration of ECP in nasal secretion and the concentration of cytokines in serum were detected at the same time. The difference and correlation among these indexes were analyzed. The best cutoff value and test efficiency of ECP chromogenic grade and concentration of nasal secretion were calculated by receiver operating characteristic curve（ROC）. Results:The concentration of ECP in nasal secretion of AR patients was significantly higher than that of healthy controls（P<0.05）. The color grade of nasal secretion detected by the test paper was positively correlated with the concentration of ECP in nasal secretion（P<0.05）, and there was significant difference among different grades（P<0.05）. There was a satisfying symmetry between the ECP color grade of nasal secretion and the serum specific IgE（sIgE） level as well as a high diagnostic consistency between them（P<0.05）. The area under the curve（AUC） of ECP concentration ROC in nasal secretion was 0.807 2, corresponding to 64% sensitivity and 85% specificity when the cutoff value was set at 0.980 5; when the cutoff value was set at 1, the AUC of nasal secretion ECP color grading was 0.941 9, corresponding to 92% sensitivity and 94% specificity. No clear correlation between the concentration of ECP in nasal secretion and serum cytokines was found（P>0.05）. Conclusion:The results of this novel test paper is in good agreement with those of serological allergens. It could serve as a preliminary test to evaluate the severity of allergy with satisfactory sensitivity and specificity, and is especially suitable in clinical practice for primary hospital.

Systemic and local cytokine profile and risk factors for persistent allergic airway inflammation in patients sensitised to house dust mite allergens

Objective

To evaluate cytokine profile, vitamin D status, symptom score and quality of life in patients with persistent allergic airway diseases sensitised to house dust mites (HDM) in comparison with healthy individuals.

Material and methods

Patients sensitized to HDM with persistent AR and having symptoms for at least 2 years with or without AA were involved into the study. Measurements of vitamin D level in serum and IL-10, IL-13, IL-17, IL-22, IL-33 and IFN-gamma in serum and nasal lavage were performed by ELISA.

Results

Eighty-one subjects were involved into the study. Serum IL-10 concentration was higher in patients with AR than in patients with AR and AA (6.71 ± 1.73 vs. 1.98 ± 0.24, p < 0.05). IFN-gamma level in nasal lavage was higher in patients with AR and AA than in patients with AR (p < 0.01) and healthy individuals (p < 0.05) (7.50 ± 0.37 vs. 6.80 ± 0.99 vs. 6.50 ± 0.22). Serum IL-22 negatively correlated with IL-22 in nasal lavage, whereas serum IFN-gamma positively correlated with IFN-gamma in nasal lavage. Positive correlation between serum IL-17 and total IgE and negative correlation between IL-17 in nasal lavage and eosinophils in nasal smear were found in patients with AR and AA. Serum IFN-gamma decreased the risk of AR for healthy individuals. Serum IL-10 and vitamin D decreased risk for development of AA for patients with AR. IL-22 in serum and IL-10 and IL-33 in nasal lavage increased this risk.

Conclusion

Novel cytokines such as IL-22, IL-17 and IL-33 and vitamin D may be involved in pathogenesis of persistent airway inflammation in patients sensitized to HDM.

Role of IL-17 in atopy-A systematic review

PURPOSE OF REVIEW

Atopy is defined as the genetic predisposition to react with type I allergic diseases such as food-, skin-, and respiratory allergies. Distinct molecular mechanisms have been described, including the known Th2 driven immune response. IL-17A (IL-17) is mainly produced by Th17 cells and belongs to the IL-17 family of cytokines, IL-17A to F. While IL-17 plays a major role in inflammatory and autoimmune disorders, more data was published in recent years elucidating the role of IL-17 in allergic diseases. The present study aimed to elaborate specifically the role of IL-17 in atopy.

METHODS

A systematic literature search was conducted in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials, regarding IL-17 and atopy/allergic diseases.

RESULTS

In total, 31 novel publications could be identified (food allergy n = 3, allergic asthma n = 7, allergic rhinitis [AR] n = 10, atopic dermatitis [AD] n = 11). In all allergic diseases, the IL-17 pathway has been investigated. Serum IL-17 was elevated in all allergic diseases. In AR, serum and nasal IL-17 levels correlated with the severity of the disease. In food allergies, serum IL-17E was also elevated in children. In AD, there is a trend for higher IL-17 values in the serum and skin specimen, while it is more expressed in acute lesions. In allergic asthma, serum IL-17 levels were increased. In two studies, higher serum IL-17 levels were found in severe persistent asthmatic patients than in intermittent asthmatics or healthy controls. Only one therapeutic clinical study exists on allergic diseases (asthma patients) using a monoclonal antibody against the IL-17 receptor A. No clinical efficacy was found in the total study population, except for a subgroup of patients with (post-bronchodilator) high reversibility.

SUMMARY

The role of IL 17 in the pathogenesis of allergic diseases is evident, but the involvement of the Th17 cytokine in the pathophysiological pathway is not conclusively defined. IL-17 is most likely relevant and will be a clinical target in subgroups of patients. The current data indicates that IL-17 is elevated more often in acute and severe forms of allergic diseases.

Lipid Profile and IL-17A in Allergic Rhinitis: Correlation With Disease Severity and Quality of Life

BACKGROUND

Recent data display the possible role of cytokines such as interleukin-10 (IL-10), IL-17 and IL-23 as a link between dyslipidemia and atopy; however, the relationship between dyslipidemia, allergic rhinitis (AR), and the underlying mechanisms involved is unclear.

PURPOSE

To measure the lipid profile and IL-17A level in AR patients in comparison to healthy controls, and correlate serum lipid level with the severity of symptoms and quality of life (QoL) of AR patients.

PATIENTS AND METHODS

Peripheral blood samples were collected from AR patients (n=70) and a control group (n=80). Samples were analyzed for serum total IgE by ELISA, serum lipid profile, and IL-17A level by ELISA. Severity of AR symptoms was assessed by visual analogue scale (VAS) score and the rhinoconjunctivitis QoL questionnaire.

RESULTS

Serum lipid profile and level of IL-17A in AR patients were significantly higher in comparison to controls (P < 0.001). Positive correlations were found between total cholesterol (TC) and the severity of AR and QoL. IL-17A was positively correlated with triglyceride (TG) level and low-density lipoprotein cholesterol (LDL-C) (P=0.011, r=0.303; P=0.043, r=0.242, respectively). Additionally, IL-17A was negatively correlated with high-density lipoprotein cholesterol (HDL-C) level (P=0.036, r=-0.251). IL-17A was positively correlated with both age and VAS score with statistical significance (P=0.033, r=0.225; P=0.011, r=0.302, respectively).

CONCLUSION

Dyslipidemia might play a potential role in the severity of AR symptoms and impairment of patients' QoL. Highlighting this association might alert physicians to evaluate the lipid profile in AR patients for timely diagnosis and treatment of dyslipidemia in an attempt to improve disease control and improve QoL.

Mechanisms of Allergen Immunotherapy in Allergic Rhinitis

PURPOSE OF REVIEW

Allergic rhinitis (AR) is a chronic inflammatory immunoglobulin (Ig) E-mediated disease of the nasal mucosa that can be triggered by the inhalation of seasonal or perennial allergens. Typical symptoms include sneezing, rhinorrhea, nasal itching, nasal congestion and symptoms of allergic conjunctivitis. AR affects a quarter of the population in the United States of America and Europe.

RECENT FINDINGS

AR has been shown to reduce work productivity in 36-59% of the patients with 20% reporting deteriorated job attendance. Moreover, 42% of children with AR report reduced at-school productivity and lower grades. Most importantly, AR impacts the patient's quality of life, due to sleep deprivation. However, a proportion of patients fails to respond to conventional medication and opts for the allergen immunotherapy (AIT), which currently is the only disease-modifying therapeutic option. AIT can be administered by either subcutaneous (SCIT) or sublingual (SLIT) route. Both routes of administration are safe, effective, and can lead to tolerance lasting years after treatment cessation. Both innate and adaptive immune responses that contribute to allergic inflammation are suppressed by AIT. Innate responses are ameliorated by reducing local mast cell, basophil, eosinophil, and circulating group 2 innate lymphoid cell frequencies which is accompanied by decreased basophil sensitivity. Induction of allergen-specific blocking antibodies, immunosuppressive cytokines, and regulatory T and B cell phenotypes are key pro-tolerogenic adaptive immune responses.

CONCLUSION

A comprehensive understanding of these mechanisms is necessary for optimal selection of AIT-responsive patients and monitoring treatment efficacy. Moreover, it could inspire novel and more efficient AIT approaches.