Neutrophil extracellular traps in upper respiratory tract secretions: insights into infectious and allergic rhinitis

Introduction

Neutrophil extracellular traps (NETs) are structures released by neutrophils in response to various infections. NETs have a biocidal role and have been demonstrated to be effective against bacteria, fungi, viruses, and parasites. Depending on the situation, NETs can protect the host from pathogen invasion or contribute to the development of autoimmune diseases such as cystic fibrosis and rheumatoid arthritis. In this study, we aimed to investigate the occurrence of NET as one of the components in upper respiratory tract secretions in infectious and allergic diseases.

Methods

Nasal mucus was collected from donors diagnosed with infectious rhinitis or allergic rhinitis. The extracellular DNA content was determined using SytoxGreen staining, and the total protein pool was determined using the microBCA method. Micrococcal nuclease was used to digest the samples and ELISA was employed to identify the NET proteins. The enzymatic activity of elastase was determined.

Results

Our findings showed that nasal mucus collected from patients with infectious rhinosinusitis contained extracellular DNA that could come from a variety of sources, responsible for increasing the density and viscosity of secretions, as well as NETs proteins. The identified enzymatic activity of NET elastase indicates the possible irritation of nasal tissues. However, the DNA content was not identified in the samples from allergic patients. In addition, we have shown in preliminary studies that therapy using N-acetylcysteine can liquefy nasal secretions.

Discussion

The study suggests that the composition of nasal mucus varies according to the cause of mucosal irritation. The presence of DNA and NET proteins can have severe consequences for the therapeutic process prolonging treatment. The low viscosity of nasal mucus in allergic patients facilitates mucosal flushing and the removal of allergens. Understanding the occurrence and role of NETs in various respiratory diseases is critical for developing effective treatment strategies that consider the complex interaction between the immune system and pathogens. The results of this study suggest that NETs may be present in upper respiratory tract secretions with an infectious background, supporting basic defense mechanisms using eosinophils and EETs. Further research is needed to explore the potential of NETs as a therapeutic target in respiratory diseases.

Flow-Based CL-SMIA for the Quantification of Protein Biomarkers from Nasal Secretions in Comparison with Sandwich ELISA

Protein biomarkers in nasal secretions can be used as a measure to differentiate between allergies, airway diseases and infections for non-invasive diagnostics. The point-of-care quantification of biomarker levels using flow-based microarray facilitates precise and rapid diagnosis and displays the potential for targeted and effective treatment. For the first time, we developed a flow-based chemiluminescence sandwich microarray immunoassay (CL-SMIA) for the quantification of nasal interferon-beta (IFN-β) on the Microarray Chip Reader-Research (MCR-R). Polycarbonate foils are used as a cost-effective surface for immobilizing capture antibodies. By using a commercially available set of anti-human IFN-β antibodies, the CL-SMIA can be compared directly to an enzyme-linked immunosorbent assay (ELISA) performed in microtiter plates concerning the bioanalytical performance and economic issues. Pre-incubation of the sample with detection antibodies facilitates the lower consumption of detection antibodies, as this allows for a longer interaction time between the antibody and the biomarker. The direct injection of pre-incubated samples into the microarray chips eliminates the adsorption of proteins in the tubing as well as the contamination of the tubing and valves of the MCR-R with clinical samples. The small flow cell allows for a low sample volume of 50 μL. The limit of detection of 4.53 pg mL^-1 was slightly increased compared to a sandwich ELISA performed on microtiter plates which were 1.60 pg mL^-1. The possibility to perform the CL-SMIA in a multiplexed mode makes it a promising assay for the rapid and cost-effective non-invasive detection of biomarkers in nasal secretions.

A diagnostic model for predicting type 2 nasal polyps using biomarkers in nasal secretion

Background

Predicting type 2 chronic rhinosinusitis with nasal polyps (CRSwNP) may help for selection of appropriate surgical procedures or pharmacotherapies in advance. However, an accurate non-invasive method for diagnosis of type 2 CRSwNP is presently unavailable.

Methods

To optimize the technique for collecting nasal secretion (NasSec), 89 CRSwNP patients were tested using nasal packs made with four types of materials. Further, Th2^low and Th2^highCRSwNP defined by clustering analysis in another 142 CRSwNP patients using tissue biomarkers, in the meanwhile, inflammatory biomarkers were detected in NasSec of the same patients collected by the selected nasal pack. A diagnostic model was established by machine learning algorithms to predict Th2^highCRSwNP using NasSecs biomarkers.

Results

Considering the area under receiver operating characteristic curve (AUC) for IL-5 in NasSec, nasal pack in polyvinyl alcohol (PVA) was superior to other materials for NasSec collection. When Th2^low and Th2^highCRSwNP clusters were defined, logistic regression and decision tree model for prediction of Th2^highCRSwNP demonstrated high AUCs values of 0.92 and 0.90 respectively using biomarkers of NasSecs. Consequently, the pre-pruned decision tree model; based on the levels of IL-5 in NasSec (≤ 15.04 pg/mL), blood eosinophil count (≤ 0.475*10⁹/L) and absence of comorbid asthma; was chosen to define Th2^lowCRSwNP from Th2^highCRSwNP for routine clinical use.

Conclusions

Taken together, a decision tree model based on a combination of NasSec biomarkers and clinical features can accurately define type 2 CRSwNP patients and therefore may be of benefit to patients in receiving appropriate therapies in daily clinical practice.

[Research progress of biomarkers in nasal secretions in endotypes diagnosis and clinical application of chronic rhinosinusitis]

With the development of studies on the endotypes of chronic rhinosinusitis （CRS） and the biomarkers of nasal secretions, the studies of CRS endotypes based on nasal secretion have become more abundant. This paper summarizes the endotypes classification of CRS, the collection methods of nasal secretion and the nasal secretion biomarkers related to the endotypes of CRS, in order to provide a reference for establishing the corresponding endotypes of CRS based on the nasal secretion biomarkers.

Utilization of Nasal Mucus to Investigate the Pathophysiology of Chronic Rhinosinusitis

BACKGROUND

Nasal mucus is proving to be a useful means by which to study the pathogenesis of chronic rhinosinusitis (CRS). Given the increase in publications examining nasal mucus and the lack of a review on this topic, we will focus on this noninvasive approach to studying CRS. Particular attention will be drawn towards inflammatory cytokines and biomarkers and their influence on disease severity.

METHODS

A literature review of papers published in English pertaining to nasal mucus was performed using the PubMed database. The search utilized combinations of the following keywords: sinusitis, polyps, sample collection, nasal mucus, or nasal secretion. Studies solely on acute or bacterial sinusitis, allergic rhinitis, or cystic fibrosis were not included.

RESULTS

A wide variety of materials and methods have been used to collect nasal mucus. Numerous assay types have been performed with the most common being ELISA, cytometric bead array, and proteomics. Most studies have focused on examining the levels of Th1/Th2 cytokines along with chemokines associated with type 2 immunity. Other factors identified include growth factors, senescence-associated proteins, complement, and antimicrobial defenses have also been identified. Nasal mucus cytokines have proven useful in cluster analysis and predicting postoperative improvement in Sino-nasal Outcome Test (SNOT-22) scores. One limitation of the use of nasal mucus is that some studies have suggested that nasal mucus does not always reflect the tissue microenvironment.

CONCLUSIONS

Nasal mucus represents a critical tool by which to examine the sinonasal microenvironment in a noninvasive manner. Unlike studies of tissue, it can be utilized in both surgically and medically managed patients and avoids the trauma of biopsies. However, studies are still needed to determine the most effective method for nasal mucus collection. Studies should also take care to confirm that nasal mucus markers do, in fact, reflect the levels of the product studied in the tissue.

A Proposed Procedure for Discriminating between Nasal Secretion and Saliva by RT-qPCR

In forensic casework, nasal secretion can be a good source of DNA. Moreover, saliva can prove useful in cases of sexual assault. However, discriminating between these body fluids is often difficult because of cross-reactivity between them on presumptive and confirmatory tests. Therefore, an RT-qPCR procedure was developed to discriminate between nasal secretion and saliva. Characteristic genes in nasal secretion and/or saliva (BPIFA1, STATH, HTN3, and PRH2) were selected as candidates. Discrimination criteria were established based on the expression levels of these markers in various body fluids. In addition, a flowchart was proposed and used to discriminate among nasal secretion, saliva, and other body fluids in various forensic samples. BPIFA1 was highly expressed in nasal secretion but was also expressed in saliva, semen, and vaginal fluid at trace levels. STATH was expressed in nasal secretion and saliva but not in other body fluids. HTN3 was specifically expressed in most of the saliva samples, as reported previously. Unexpectedly, PRH2 was expressed in only a few saliva samples. Using the proposed criteria and flowchart, nasal secretion and saliva were successfully discriminated among the various body fluids tested. The developed procedure could be useful in forensic casework.

Dry Eye and Dry Nose Caused by the Effect of Allergic Rhinitis on Tear and Nasal Secretion Osmolarity

OBJECTIVE

Allergic rhinitis is a type 1 hypersensitivity reaction of immunoglobulin E in the rhino-ocular mucosa. This study was planned to demonstrate in patients with allergic rhinitis to evaluate changes in tear, nasal secretions, and blood osmolarity compared to healthy individuals.

METHOD

Forty allergic rhinitis patients, 25 patients with acute upper respiratory tract infections, and 26 healthy participants were included in the study. Positive patients with allergic symptoms and skin prick test results were included in the allergic rhinitis group. Tear, nasal secretion, and blood osmolarity values were examined for the 3 groups.

RESULT

In patients with allergic rhinitis, tear and nasal secretion osmolarity values were significantly higher in patients with acute upper respiratory tract infections and those of the healthy participants (P = .001, P = .038). In blood osmolarity measurements, there was no statistical difference between the groups (P = .489). In patients with allergic rhinitis, Schirmer test results were significantly shorter than patients who had acute upper respiratory tract infection and those of the healthy participants (P = .001, P = .001). Patients with allergic rhinitis and acute upper respiratory tract infections had significantly shorter Schirmer test results than in healthy participants (P = .001, P = .001).

CONCLUSION

Tear osmolarity was increased in allergic rhinitis patients, and this was thought to lead to dry eye findings. In the presence of allergic rhinitis, nasal secretions were found more hyperosmolar than tears. Nasal secretion osmolarity was higher in allergic rhinitis patients than in patients with acute upper respiratory tract infections and control group.

[Biophysical mechanisms of dehydration of nasal cavity secretion in inflammatory diseases of the upper respiratory tract]

The purpose of the study is an experimental-theoretical study of the mechanisms of structuring the secretion of the nasal cavity, in the process of its dehydration in inflammatory diseases of the upper respiratory tract. The work shows the general patterns of dehydration of natural biological fluids and their model solutions. Simulation of dehydration of the secret allowed us to identify the most informative parameters of changes in its composition in pathology and to develop criteria for diagnosing the inflammatory process of the VDP using the wedge-shaped dehydration method. The study clarified the mechanisms of dehydration of biological fluid, which expanded the possibilities of diagnosing diseases of the VDP.

The Impact of Septal Deviation on Intranasal Schirmer Test Values

Objective

Intranasal Schirmer test serves as an objective measurement for evaluation of nasal secretion and humidity. This study aimed to evaluate the effect of septal deviation on nasal secretion and humidity by measuring the intranasal Schirmer test values in patients who had septal deviation and compare it to the values of our healthy volunteers.

Methods

The study included 52 patients with nasal septum deviation and 52 volunteers without any rhinologic complaints or deviated nasal septum. Intranasal Schirmer test was performed to all patients and volunteers for both nasal cavities.

Results

The intranasal Schirmer test values of the convex (deviated) side were lower than that of the concave (non-deviated) side (20.71 and 23.35 respectively); although this difference was not statistically significant (p=0.054,). After excluding the four patients with equal Schirmer test results on both sides, 70% (34/48) of our patients had lower intranasal Schirmer test values on the deviated side. There was no statistically significant difference between the Schirmer test values of the patients with septal deviation and the volunteers without septal deviation (p>0.05).

Conclusion

The Schirmer test values of the deviated sides were less than the values of the contralateral side in majority of our patients. This finding supports the negative effect of nasal septum deviation on nasal humidification, although the difference did not reach statistical significance.

The use of specific immunoglobulin E in nasal secretions for the diagnosis of allergic rhinitis

OBJECTIVE

Although local specific immunoglobulin (sIgE) has been employed as a diagnostic criterion for allergic rhinitis (AR), the use of local sIgE has not been fully evaluated in the diagnosis of allergic rhinitis. The aim of this study was to evaluate the use of nasal secretion sIgE in the diagnosis of allergic rhinitis.

METHODS

A total of 51 patients (27 males and 24 females, mean age = 33.3 years) with rhinitis symptoms were enrolled consecutively from the allergy-rhinology clinic of Beijing TongRen Hospital (Beijing, People's Republic of China). Questionnaires were completed by each participant at recruitment to record demographic data, nasal symptom severity, and physician-diagnosed comorbid asthma. The severity of nasal obstruction, rhinorrhea, sneezing, and nasal/eye itching was recorded according to a visual analogue scale (VAS) of 10 cm. Sensitization to Dermatophagoides pteronyssinus, Dermatophagoides farinae, mugwort, Candida albicans, Penicillium notatum, Alternaria, Cladosporium, and Aspergillus were assessed according to presence of sIgE antibodies to these allergens in serum and nasal secretions.

RESULTS

VAS scores of the participants ranged from 11 to 25 (mean = 17), and 14 (27.5%) patients had comorbid asthma. Based on serum sIgE, 31 (60.8%) patients were allergic to mugwort, 14 (27.5%) to Dermatophagoides, and three (5.9%) to fungal allergens. Based on nasal secretion sIgE, 32 (62.7%) patients were allergic to mugwort, 12 (23.5%) to Dermatophagoides, and three (5.9%) to fungal allergens. The local mugwort sIgE level and serum mugwort sIgE level were positively correlated with each other and with VAS scores.

CONCLUSION

sIgE level in nasal secretions of subjects with rhinitis is a reliable noninvasive alternative to serum sIgE for diagnosis of allergic rhinitis.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:E311-E315, 2018.

Inhibitory action of levocetirizine on the production of eosinophil chemoattractants RANTES and eotaxin in vitro and in vivo

Eosinophils are well known to play essential roles in the development and maintenance of allergic diseases. However, the influence of histamine H1 receptor antagonists on eosinophil functions, especially chemokine production, are not well-defined. Therefore, in the present study, we examined the influence of histamine H1 receptor antagonist on chemokine production by eosinophils through the use of levocetirizine in vitro and in vivo. Eosinophils prepared from mice were stimulated with specific antigens in the presence of different concentrations of levocetirizine. After 24 h, regulated on activation normal T cell expressed and secreted (RANTES) and eotaxin levels in culture supernatants were measured by enzyme-linked immunosorbent assay (ELISA). Patients with Japanese cedar pollinosis were treated with 5 mg levocetirizine once a day for four weeks during the pollen season (February 2012 to April 2012). RANTES and eotaxin levels in nasal secretions were also examined by ELISA. The addition of levocetirizine to eosinophil cultures caused a dose-dependent decrease in the ability of cells to produce RANTES and eotaxin in response to antigen stimulation, and the minimum concentration that caused a significant decrease was 0.05 μM. Although cetirizine also exerted suppressive effects on the production of RANTES and eotaxin by eosinophils, the minimum concentration that caused significant suppression was 0.15 μM, which was three-times higher than that of levocetirizine. Oral administration of levocetirizine for four weeks also reduced RANTES and eotaxin levels in nasal secretions from patients with pollinosis, along with attenuation of clinical symptoms. The ability of levocetirizine to reduce RANTES and eotaxin levels may account, at least in part, for the clinical efficacy of the agent for allergic disorders, including allergic rhinitis.

Nasal levels of soluble IL-33R ST2 and IL-16 in allergic rhinitis: inverse correlation trends with disease severity

BACKGROUND

Serum levels of IL-16, IL-33 and the decoy receptor of IL-33, soluble ST2, are elevated in allergic rhinitis. Recent studies show that IL-16, soluble ST2 or anti-IL-33 reduce type 2 cytokines (such as IL-5) and eosinophilia in murine models of allergic asthma or allergic rhinitis respectively.

OBJECTIVE

In this study, we studied the release of IL-5, IL-16, IL-33 and soluble ST2 in allergic rhinitis patients after nasal allergen challenge and natural pollen exposure.

METHODS

The nasal lavages of 15 allergic and 14 non-allergic volunteers were collected during the pollen allergy season. In addition, six allergic volunteers underwent unilateral nasal allergen and control challenge out of season and nasal secretions and sera were collected. IL-5, IL-16, IL-33 and soluble ST2 in nasal secretions and sera were measured by electrochemiluminescent assay or ELISA, respectively.

RESULTS

Nasal IL-5, IL-16 and soluble ST2 levels were significantly increased in seasonally pollen exposed allergic volunteers compared to control subjects (P < 0.001, P = 0.018 and P = 0.002 respectively), whereas IL-33 remained undetectable. Nasal IL-16 showed a weak inverse correlation trend with nasal symptoms (r = -0.48, P = 0.07). Nasal soluble ST2 concentrations were inversely correlated with nasal symptoms (r = -0.61, P = 0.02) and positively correlated with IL-16 (r = 0.56, P = 0.03). Significant increases of nasal IL-5, IL-16 and ST2 but not IL-33 were observed after nasal allergen challenge. At 24 h after allergen challenge, local ST2 and IL-5 concentrations showed an inverse correlation trend (r = -0.83, P = 0.04). Serum levels of IL-5, IL-16 and soluble ST2 rose in at least five of six volunteers tested at 5 or 24 h post-challenge.

CONCLUSIONS AND CLINICAL RELEVANCE

The observed upregulation of soluble ST2 and IL-16 after nasal allergen challenge and during peak pollination season suggests potential regulatory roles of these cytokines in the inflammatory reaction in allergic rhinitis.

Cytokine correlation between sinus tissue and nasal secretions among chronic rhinosinusitis and controls

OBJECTIVES/HYPOTHESIS

Compare cytokine levels in sinus tissue to sinus secretions from controls and chronic rhinosinusitis patients.

STUDY DESIGN

In vitro.

METHODS

Polyurethane foam sponges were placed into middle meati of patients with chronic rhinosinusitis without nasal polyps (CRSsNP), with polyps (CRSwNP), and controls. Sinus biopsies were then taken from the same location. Protein levels of tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ), and interleukins (IL) 2, 4, 6, 8, 10, and 17A were measured via cytometric bead assay for each sample. Protein values from sinus tissue and secretions were compared with Pearson's correlation between samples as well as one-way ANOVA with posthoc t test between groups.

RESULTS

Samples from 43 patients in total were examined. Mucus was measured from 10 controls, 11 CRSsNP and 10 CRSwNP, and sinus tissue was measured from 10 controls, 15 CRSsNP and 10 CRSwNP. IL-8 and IFN-γ levels were outside of the detectable range of the assay. Levels of secreted IL-2, 4, 6, 10, and 17A correlated with tissue levels (P < 0.05 for all, r > 0.49) while TNF-α did not (P = 0.71). CRSsNP had elevated mucus levels of IL-2, 4, 6, 10, and 17A compared to controls. CRSwNP had elevated mucus levels of IL-4, 6, 10, 17A, and TNF-α compared to controls.

CONCLUSIONS

Cytokine levels in sinus secretions correlate with levels in sinus tissue and are elevated in CRS versus control based on Th1/Th2 skewing.