Nasal Response Research Articles

Protection of Rabbits Against Colonization and Morbidity Associated With Toxigenic Pasteurella multocida by Immunization With Inactivated Heat-labile Toxin.

Pasteurella multocida is a significant cause of morbidity and mortality in rabbits, as well as other species. Some isolates elaborate a heat-labile toxin (PMT) that has been shown to be an important virulence factor. Though previous studies have demonstrated protective immunity can be conferred via immunization of rabbits with heat-inactivated PMT (IPMT), we investigated the ability of immunization to impact colonization of P. multocida. Rabbits were immunized at days 0, 7 and 14 with either phosphate buffered saline (PBS), the mucosal adjuvant cholera toxin (CT), IMPT or IPMT + CT. Male New Zealand white rabbits were used and confirmed to be free of P. multocida prior to experimentation. Serum IgG and nasal lavage fluid IgA responses directed against PMT were found in rabbits immunized with IPMT, with or without CT, but not in those immunized with only PBS or CT; and the addition of CT to IPMT enhanced the response. Significantly more P. multocida CFUs (p≤0.05) were cultured from the lungs of rabbits immunized with IPMT, with or without CT, compared to those administered only PBS or CT, although no differences were observed in nasal lavage fluid samples. Further, immunization IPMT, with or without CT, conferred protection against pleuritis and pneumonia. PMT, in addition to its role as a virulence factor, may serve as a colonization factor for P. multocida in the lungs of rabbits.

Efficacy of Capsaicin for Non-allergic Rhinitis: An Updated Systematic Review and Meta-analysis.

Non-allergic rhinitis (NAR) is a prevalent condition with limited effective treatments. Capsaicin, an agonist of the transient receptor potential vanilloid subfamily 1 (TRPV1) receptor, has emerged as a potential therapeutic option for NAR by targeting heightened nasal reactivity. This systematic review and meta-analysis, conducted in accordance with PRISMA guidelines and registered on PROSPERO, evaluated the efficacy of capsaicin for NAR treatment. Nine studies with placebo-controlled group were included, with primary outcomes assessed as total nasal symptom scores (TNSS), visual analog scale (VAS) scores, and the proportion of therapeutic responders. Meta-analysis revealed significant improvements in TNSS and VAS scores, along with a higher proportion of therapeutic responders in patients receiving capsaicin treatment compared to placebo. While some studies demonstrated reductions in substance P levels and TRPV1 expression after capsaicin treatment, further investigation is warranted. This meta-analysis provides preliminary evidence suggesting that capsaicin treatment holds promise for alleviating symptoms in patients with NAR. However, the limited number of studies and methodological heterogeneity necessitate larger and more rigorously designed clinical trials with standardized methodologies and advanced diagnostic techniques to establish their definitive roles in clinical practice.

Allergen immunotherapy effectiveness in specific nasal reactivity of children with local allergic rhinitis.

Background.Allergen immunotherapy (AIT) is the only disease-modifying treatment in allergy. Its efficacy has been demonstrated in the treatment of Local Allergic Rhinitis (LAR) in adults. This study intends to evaluate the effectiveness of AIT in specific nasal reactivity of paediatric patients with LAR. Methods.Patients diagnosed with LAR to Dermatophagoides pteronyssinus (Dp) were submitted to subcutaneous AIT (SCIT) (depigmented-polymerized Dp allergen extracts) for 3 years. Nasal allergen challenge (NACs) with Dp extract were performed before and 3 years after AIT. NAC response was assessed with peak nasal inspiratory flow (PNIF) and symptom score of Lebel. NACs were considered positive when there was a flow decrease of ≥ 20% in PNIF and a score of symptoms ≥ 3 points. Demographic data and NAC results were analysed. Results.We included 32 paediatric patients (mean age 9.9±3.08 years, 18 female) and 10 adult patients, (mean age 30.4±12.2 years, 7 female). The symptom score obtained at the 1st minute, 5th minute, 15th minute and 30th minute in response to NAC, were reduced after AIT. The nasal inspiratory flow decrease induced by NAC was also reduced after AIT. This reduction in nasal reactivity was observed in paediatric and in adult patients, both with statistical significance. Conclusions.AIT induced a decrease in Dp-nasal specific reactivity in children with LAR. This decline of nasal response to allergen exposure, after AIT treatment, emphasis the interest of this therapeutic approach in LAR, even in paediatric patients.

Multi-antigen intranasal vaccine protects against challenge with sarbecoviruses and prevents transmission in hamsters

Immunization programs against SARS-CoV-2 with commercial intramuscular vaccines prevent disease but are less efficient in preventing infections. Mucosal vaccines can provide improved protection against transmission, ideally for different variants of concern (VOCs) and related sarbecoviruses. Here, we report a multi-antigen, intranasal vaccine, NanoSTING-SN (NanoSTING-Spike-Nucleocapsid), eliminates virus replication in both the lungs and the nostrils upon challenge with the pathogenic SARS-CoV-2 Delta VOC. We further demonstrate that NanoSTING-SN prevents transmission of the SARS-CoV-2 Omicron VOC (BA.5) to vaccine-naïve hamsters. To evaluate protection against other sarbecoviruses, we immunized mice with NanoSTING-SN. We showed that immunization affords protection against SARS-CoV, leading to protection from weight loss and 100% survival in mice. In non-human primates, animals immunized with NanoSTING-SN show durable serum IgG responses (6 months) and nasal wash IgA responses cross-reactive to SARS-CoV-2 (XBB1.5), SARS-CoV and MERS-CoV antigens. These observations have two implications: (1) mucosal multi-antigen vaccines present a pathway to reducing transmission of respiratory viruses, and (2) eliciting immunity against multiple antigens can be advantageous in engineering pan-sarbecovirus vaccines.

M6A mRNA methylation-mediated MAPK signaling modulates the nasal mucosa inflammatory response in allergic rhinitis.

Allergic rhinitis (AR) is a complex disease in which gene-environment interactions contribute to its pathogenesis. Epigenetic modifications, such as N6-methyladenosine (m6A) modification of mRNA, play important roles in regulating gene expression in multiple physiological and pathological processes. However, the function of m6A modification in AR and the inflammatory response is poorly understood. We used the ovalbumin (OVA) and aluminum hydroxide to induce an AR mouse model. Nasal symptoms, histopathology, and serum cytokines were examined. We performed combined m6A and RNA sequencing to analyze changes in m6A modification profiles. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and methylated RNA immunoprecipitation sequencing qPCR (MeRIP-qPCR) were used to verify differential methylation of mRNAs and the m6A methylation level. Knockdown or inhibition of Alkbh5 in nasal mucosa of mice was mediated by lentiviral infection or IOX1 treatment. We showed that m6A was enriched in a group of genes involved in MAPK signaling pathway. Moreover, we identified a MAPK pathway involving Map3k8, Erk2, and Nfκb1 that may play a role in the disrupted inflammatory response associated with nasal inflammation. The m6A eraser, Alkbh5, was highly expressed in the nasal mucosa of AR model mice. Furthermore, knockdown of Alkbh5 expression by lentiviral infection resulted in high MAPK pathway activity and a significant nasal mucosa inflammatory response. Our findings indicate that ALKBH5-mediated m6A dysregulation likely contributes to a nasal inflammatory response via the MAPK pathway. Together, our data show that m6A dysregulation mediated by ALKBH5, is likely to contribute to inflammation of the nasal mucosa via the MAPK signaling pathway, suggesting that ALKBH5 is a potential biomarker for AR treatment.

High burden of viruses and bacterial pathobionts drives heightened nasal innate immunity in children.

Studies during the COVID-19 pandemic showed that children had heightened nasal innate immune responses compared with adults. To evaluate the role of nasal viruses and bacteria in driving these responses, we performed cytokine profiling and comprehensive, symptom-agnostic testing for respiratory viruses and bacterial pathobionts in nasopharyngeal samples from children tested for SARS-CoV-2 in 2021-22 (n = 467). Respiratory viruses and/or pathobionts were highly prevalent (82% of symptomatic and 30% asymptomatic children; 90 and 49% for children <5 years). Virus detection and load correlated with the nasal interferon response biomarker CXCL10, and the previously reported discrepancy between SARS-CoV-2 viral load and nasal interferon response was explained by viral coinfections. Bacterial pathobionts correlated with a distinct proinflammatory response with elevated IL-1β and TNF but not CXCL10. Furthermore, paired samples from healthy 1-year-olds collected 1-2 wk apart revealed frequent respiratory virus acquisition or clearance, with mucosal immunophenotype changing in parallel. These findings reveal that frequent, dynamic host-pathogen interactions drive nasal innate immune activation in children.

Posterior Nasal Nerve Ablation as a Viable Treatment Option for the Primary Symptom of Postnasal Drip.

Postnasal drip (PND) syndrome is a prevalent complaint encountered in otolaryngology practices. PND may be refractory to medical therapy, and surgical treatments are complicated by side effects. While posterior nasal nerve (PNN) ablation has demonstrated efficacy for chronic rhinitis overall, we sought to examine the effect of PNN ablation for patients with PND as their primary complaint. This is a retrospective case series study of 40 chronic rhinitis (CR) patients with a primary complaint of PND. Included patients had to have failed medical therapy such as anti-cholinergic nasal sprays, reflux treatments, and/or nasal steroids. Primary outcome measures included 22 item Sino-Nasal Outcome Test (SNOT-22) PND component and Total Nasal Symptom Score. Secondary outcome measure was subjective improvement, defined as a > 30% improvement in PND symptoms. Median follow-up was 138 days (interquartile range: 72-193). 72.5% (29/40) of patients reported at least a 30% improvement in PND symptoms. Mean PND SNOT-22 scores were 4.2/5 (SD = 0.8) pre-procedure versus 1.9/5 (SD = 1.3) post-procedure (P = .001). PNN ablation response did not correlate to ipratropium bromide nasal spray response, although younger and non-smoker patients had better response rates. This exploratory study of PNN ablation for the primary symptom of PND demonstrates efficacy as assessed by the PND component of SNOT-22 and subjective improvement. These results can be useful in guiding physician-patient discussions in determining treatment options for medically refractory PND.

Fabrication of chitosan-based emulsion as an adjuvant to enhance nasal mucosal immune responses

Nasal vaccine is a non-invasive vaccine that activates systemic and mucosal immunity in the presence of an adjuvant, thereby enhancing immune function. In this work, chitosan/oligochitosan/tween 80 (CS-COS-T80) co-stabilized emulsion was designed and further used as the nasal adjuvant. CS-COS-T80 emulsion exhibited outstanding stability under pH 6–8 with uniformly dispersed droplets and nano-scale particle size (<0.25 μm), and maintained stable at 4 °C for 150-day storage. Addition of model antigen ovalbumin (OVA) had no effect on the stability of CS-COS-T80 emulsion. In vivo nasal immunity indicated that CS-COS-T80 emulsion prolonged the retention time of OVA in the nasal cavity (from 4 to 8 h to >12 h), as compared to T80-emulsion. CS-COS-T80 emulsion produced a stronger mucosal immune response to OVA, with secretory IgA levels 5-fold and 2-fold higher than those of bare OVA and commercial adjuvant MF59, respectively. Compared to MF59, CS-COS-T80 induced a stronger humoral immune response and a mixed Th1/Th2 immune response of OVA after immunization. Furthermore, in the presence of CS-COS-T80 emulsion, the secretion of IL-4 and IFN-γ and the activation of splenocyte memory T-cell differentiation increased from 173.98 to 210.21 pg/mL and from 75.46 to 104.01 pg/mL, respectively. Therefore, CS-COS-T80 emulsion may serve as a promising adjuvant platform.

Sex-biased immunogenicity of a mucosal subunit vaccine against SARS-CoV-2 in mice.

Current vaccines against COVID-19 administered via parenteral route have limited ability to induce mucosal immunity. There is a need for an effective mucosal vaccine to combat SARS-CoV-2 virus replication in the respiratory mucosa. Moreover, sex differences are known to affect systemic antibody responses against vaccines. However, their role in mucosal cellular responses against a vaccine remains unclear and is underappreciated. We evaluated the mucosal immunogenicity of a booster vaccine regimen that is recombinant protein-based and administered intranasally in mice to explore sex differences in mucosal humoral and cellular responses. Our results showed that vaccinated mice elicited strong systemic antibody (Ab), nasal, and bronchiole alveolar lavage (BAL) IgA responses, and local T cell immune responses in the lung in a sex-biased manner irrespective of mouse genetic background. Monocytes, alveolar macrophages, and CD103+ resident dendritic cells (DCs) in the lungs are correlated with robust mucosal Ab and T cell responses induced by the mucosal vaccine. Our findings provide novel insights into optimizing next-generation booster vaccines against SARS-CoV-2 by inducing spike-specific lung T cell responses, as well as optimizing mucosal immunity for other respiratory infections, and a rationale for considering sex differences in future vaccine research and vaccination practice.

Interferon signaling in the nasal epithelium distinguishes among lethal and common cold coronaviruses and mediates viral clearance

All respiratory viruses establish primary infections in the nasal epithelium, where efficient innate immune induction may prevent dissemination to the lower airway and thus minimize pathogenesis. Human coronaviruses (HCoVs) cause a range of pathologies, but the host and viral determinants of disease during common cold versus lethal HCoV infections are poorly understood. We model the initial site of infection using primary nasal epithelial cells cultured at an air-liquid interface (ALI). HCoV-229E, HCoV-NL63, and human rhinovirus-16 are common cold-associated viruses that exhibit unique features in this model: early induction of antiviral interferon (IFN) signaling, IFN-mediated viral clearance, and preferential replication at nasal airway temperature (33 °C) which confers muted host IFN responses. In contrast, lethal SARS-CoV-2 and MERS-CoV encode antagonist proteins that prevent IFN-mediated clearance in nasal cultures. Our study identifies features shared among common cold-associated viruses, highlighting nasal innate immune responses as predictive of infection outcomes and nasally directed IFNs as potential therapeutics.

A pediatric randomized, controlled trial of German cockroach subcutaneous immunotherapy

Cockroach allergy contributes to morbidity among urban children with asthma. Few trials address the effect of subcutaneous immunotherapy (SCIT) with cockroach allergen among these at-risk children. We sought to determine whether nasal allergen challenge (NAC) responses to cockroach allergen would improve following 1 year of SCIT. Urban children with asthma, who were cockroach-sensitized and reactive on NAC, participated in a year-long randomized double-blind placebo-controlled SCIT trial using German cockroach extract. The primary endpoint was the change in mean Total Nasal Symptom Score (TNSS) during NAC after 12 months of SCIT. Changes in nasal transcriptomic responses during NAC, skin prick test wheal size, serum allergen-specific antibody production, and T-cell responses to cockroach allergen were assessed. Changes in mean NAC TNSS did not differ between SCIT-assigned (n= 28) versus placebo-assigned (n= 29) participants (P= .63). Nasal transcriptomic responses correlated with TNSS, but a treatment effect was not observed. Cockroach serum-specific IgE decreased to a similar extent in both groups, while decreased cockroach skin prick test wheal size was greater among SCIT participants (P= .04). A200-fold increase in cockroach serum-specific IgG4 was observed among subjects receiving SCIT (P< .001) but was unchanged in the placebo group. T-cell IL-4 responses following cockroach allergen stimulation decreased to a greater extent among SCIT versus placebo (P= .002), while no effect was observed for IL-10 or IFN-γ. A year of SCIT failed to alter NAC TNSS and nasal transcriptome responses to cockroach allergen challenge despite systemic effects on allergen-specific skin tests, induction of serum-specific IgG4 serum production and down-modulation of allergen-stimulated T-cell responses.

Sex-biased immunogenicity of a mucosal subunit vaccine against SARS-CoV-2 in mice

Abstract Current vaccines against COVID-19 administered via parenteral route have limited ability to induce mucosal immunity. There is a need for an effective mucosal vaccine to combat SARS-CoV-2 virus replication in the respiratory mucosa. Moreover, sex differences are known to affect systemic antibody responses against vaccines. However, their role in mucosal cellular responses against a vaccine remains unclear and is underappreciated. We evaluated the mucosal immunogenicity of a booster vaccine regimen that is recombinant protein-based and administered intranasally in mice to explore sex differences in mucosal humoral and cellular responses. Our results showed that vaccinated mice elicited strong systemic antibody (Ab), nasal, and bronchiole alveolar lavage (BAL) IgA responses, and local T cell immune responses in the lung in a sex-biased manner irrespective of mouse genetic background. Monocytes, alveolar macrophages, and CD103+ resident dendritic cells in the lungs are correlated with robust mucosal Ab and T cell responses induced by the mucosal vaccine. Our findings provide novel insights into optimizing next-generation booster vaccines against SARS-CoV-2 by inducing spike-specific lung T cell responses, and a rationale for considering biological sex differences in future vaccine research and vaccination practice.

Age-specific nasal epithelial responses to SARS-CoV-2 infection

Children infected with SARS-CoV-2 rarely progress to respiratory failure. However, the risk of mortality in infected people over 85 years of age remains high. Here we investigate differences in the cellular landscape and function of paediatric (<12 years), adult (30–50 years) and older adult (>70 years) ex vivo cultured nasal epithelial cells in response to infection with SARS-CoV-2. We show that cell tropism of SARS-CoV-2, and expression of ACE2 and TMPRSS2 in nasal epithelial cell subtypes, differ between age groups. While ciliated cells are viral replication centres across all age groups, a distinct goblet inflammatory subtype emerges in infected paediatric cultures and shows high expression of interferon-stimulated genes and incomplete viral replication. In contrast, older adult cultures infected with SARS-CoV-2 show a proportional increase in basaloid-like cells, which facilitate viral spread and are associated with altered epithelial repair pathways. We confirm age-specific induction of these cell types by integrating data from in vivo COVID-19 studies and validate that our in vitro model recapitulates early epithelial responses to SARS-CoV-2 infection.

Clinical Relevance of Lepidoglyphus destructor Sensitisation in Allergic Rhinitis: Nasal Provocation Test as in vivo Assessment

Background: Dust mites are the leading cause of respiratory allergic diseases worldwide. Allergy to storage mites (SMs) has mostly been related to occupational exposures. However, recent studies have shown that sensitisation to SM, such as Lepidoglyphus destructor (Lep d), is of considerable importance also in urban populations, with high prevalence in dust samples of domestic environments. Co-sensitisation between house dust mites (HDMs) and SM is now regarded as very frequent in some regions, and cross-reactivity between them seems to be narrow. Therefore, SM allergenic capacity is increasingly a subject of study. The nasal provocation test (NPT), as an in vivo technique, could be considered the gold standard for the clinical relevance assessment of an allergen, in polysensitised rhinitis patients. Objective: The objective of this study was to analyse the clinical relevance of the SM Lep d, by assessing the relationship between in vivo sensitisation and expression of allergic respiratory disease in an urban setting. Patients and Methods: In our study, we enrolled a total of 32 allergic patients with rhinitis (with or without asthma) with proven sensitisation by skin prick test (SPT) and specific IgE (sIgE) to HDMs and/or SM. Patients underwent NPT with Lep d using subjective (Lebel Symptom Score Scale) and objective measurements (peak nasal inspiratory flow [PNIF]) for assessment of nasal response. Results: Most of the patients with positive SPT and sIgE to Lep d had a positive NPT (24/27; 89%). True Lep d allergy, assessed by a positive NPT, could be predicted by a SPT wheal size >9.7 mm and a sIgE >0.42 kUA/L, with 100%/95.7% sensitivity and 75.0%/83.3% specificity, respectively. Co-sensitisation between Lep d and Der p was high, 75.0%. Asthma was more frequent in the positive Lep d NPT group (54 vs. 12%, p < 0.05). Significantly more patients from this group reported physical exercise, nonspecific irritants, and respiratory infections as relevant triggers of respiratory symptoms (p < 0.01–p < 0.05). Conclusions: To our knowledge, this is the first study to show that sensitisation to Lep d may have clinical relevance in a non-occupational setting. In this group, there seems to be a relationship between allergy to Lep d and severity of respiratory disease, with more bronchial inflammation, when comparing with mite-allergic patients sensitised only to HDM. Therefore, the authors consider that sensitisation to Lep d should be considered when assessing and treating allergic respiratory disease in urban environments.

The nasal and systemic inflammatory responses in early phase of acute radiation rhinosinusitis: A pilot study.

Disease severity in acute radiation rhinosinusitis (ARRS) peaks after radiation therapy. ARRS is mainly local inflammation, manifested by increased pro-inflammatory cytokines. Intranasal corticosteroids are effective anti-inflammatory drugs in the treatment of ARRS.

Exposure of nonylphenol promoted NLRP3 inflammasome and GSDMD-mediated pyroptosis in allergic rhinitis mice

Studies have confirmed that the intake of nonylphenol (NP) can increase nasal symptoms, eosinophils, and Th2 responses in allergic rhinitis (AR) mice. However, the molecular mechanism of NP exacerbating AR inflammatory response remains unclear. Recent data suggest that NOD-like receptor 3 (NLRP3) inflammasome-mediated pyroptosis contributes to AR development. To investigate the effects of NP on NLRP3 inflammasomes and pyroptosis, an AR mouse model induced by ovalbumin (OVA) was established and treated with 0.5 mg/kg/d NP every other day. Nasal symptoms were evaluated after the final OVA instillation. Mast cells and Eosinophils in the nasal mucosa were observed using toluidine blue and Sirius red staining, respectively. The levels of NLRP3, Caspase-1, ASC, phospho–nuclear factor kappa B (NF-κB) p65, interleukin (IL)-6, TNF-α, IL-18, GSDMD and IL-1β, were assessed by using immunohistochemical staining, ELISA, quantitative real-time PCR, or Western blot. Exposure to NP aggravates AR symptoms and promotes eosinophils, mast cells, and inflammatory factors release, along with significantly increased of NF–κB, NLRP3, Caspase-1, ASC, and GSDMD. It was concluded that NP exposure promotes NLRP3 inflammasome and GSDMD-mediated pyroptosis of the nasal mucosa. Targeted of NLRP3 and GSDMD-mediated pyroptosis may be a novel therapeutic strategy for AR exposed to NP.

α7 nicotinic acetylcholine receptor agonist attenuates allergen-induced immediate nasal response in murine model of allergic rhinitis.

The expression of nicotinic acetylcholine receptor (nAChR) subunits on various immune cells suggests their involvement in allergic rhinitis. However, how exactly they contribute to this pathogenesis is not yet confirmed. Our present study examined the therapeutic potential of GTS-21, an α7 nAChR agonist, for treating allergic rhinitis by employing its mouse models. GTS-21 treatment reduced allergen-induced immediate nasal response in ovalbumin (OVA)-sensitized model. However, nasal hyperresponsiveness or eosinophil infiltration elicited in either the OVA-sensitized or T helper 2 cell-transplanted model was not affected by GTS-21. GTS-21 did not alter allergen-induced passive cutaneous anaphylaxis response in anti-dinitrophenyl IgE-sensitized mice. This evidence implies GTS-21's potential to alleviate allergic rhinitis without perturbing T cells or mast cells.

LONGITUDINAL EVALUATION OF EFFICACY OF SUBLINGUAL IMMUNOTHERAPY IN PEDIATRIC PERENNIAL ALLERGIC RHINITIS USING LABORATORY EXAMINATIONS AND IN VIVO BIOMARKERS

The purpose of this study was to evaluate the efficacy of sublingual immunotherapy (SLIT) with house dust mite (HDM) on pediatric perennial allergic rhinitis (AR) based on longitudinal assessment of nasal symptoms, laboratory examination, and in vivo biomarkers. The subjects included 40 children with perennial AR who had SLIT with HDM for 2 years. Nasal symptoms, medications, skin prick tests, nasal provocation tests, and peripheral blood tests were evaluated before, 6 months, one year and two years after the onset of SLIT. Total nasal symptom scores, prick test wheal diameter, and peripheral blood eosinophil count decreased in 6 months. Total nasal symptom scores continued to decrease from 6 months to 2 years. Symptom-medication scores and nasal provocation test responses decreased in 1 year. Symptom-medication scores continued to decline from 1 to 2 years. Medication scores and nasal eosinophilia decreased in 2 years. Serum specific IgE to HDM slightly increased transiently and decreased in 2 years. The severity of symptoms and specific IgE to HDM at the baseline, and changes of symptoms and specific IgE to HDM during the first six months and first one year of SLIT were correlated with improvement in symptom scores over two years of SLUT. TNSS at baseline was correlated with that at second year. Longitudinal assessment of symptoms, allergen specific IgE, and in vivo biomarkers showed the effectiveness of SLIT. Symptom scores and allergen specific IgE may also be early predictive factors of SLIT efficacy in children with AR.

Investigation of Nasal Mucosal IgA Responses in the Population Following COVID-19 Pandemic - China, September 2022-August 2023.

Mucosal IgA plays a crucial role in host immunity against respiratory viruses. Recent studies suggest that it has the potential to mitigate the transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant. However, a comprehensive population-based analysis examining mucosal IgA levels following the winter 2022 wave of the coronavirus disease 2019 (COVID-19) pandemic is yet to be conducted. In our study involving 3,421 participants, we documented IgA responses subsequent to SARS-CoV-2 infection. A significant proportion of individuals sustained increased levels of IgA for over six months. These levels were also observed in individuals with prior infections who underwent asymptomatic reinfections, indicating an active production of IgA antibodies. Further, individuals with multiple vaccinations or severe symptoms tended to display elevated IgA levels after recovery. IgA in the nasal mucosa is crucial for defense against SARS-CoV-2 infection. These insights can enhance our knowledge of immune responses following infection and have provided certain reference values for disease prevention and control strategies.

Local allergic rhinitis in children: identification and characterization in a specialty outpatient clinic.

Background. Local Allergic Rhinitis (LAR) is a phenotype defined by rhinitis symptoms with negative responses to systemic sensitization tests but with an exclusively nasal allergic inflammatory response. Data on the pediatric age group is scarce, and no Latin American data has been published so far. Methods. Nasal Allergen Challenge (NAC) was performed with Dermatophagoides pteronyssinus and Blomia tropicalis in six- to 18-year-old patients diagnosed with rhinitis and no systemic sensitization. NAC was monitored using subjective parameters and acoustic rhinometry. The study aimed to identify LAR in child and adolescent subjects previously diagnosed with non-allergic rhinitis (NAR) in a Brazilian specialty outpatient clinic (Allergy and Immunology). Results. During the study period, we analyzed 758 skin prick tests (SPT). Of those, 517 (68.2%) were diagnosed with rhinitis. Among those, 18.4% (95/517) had a negative SPT, meeting the criteria for inclusion in the study. Twenty-five patients underwent NAC, and 40% (10/25) of them, previously considered to have NAR, had a positive test and were reclassified as having LAR. Based on the analyzed characteristics, clinically differentiating LAR from NAR was impossible. Conclusions. This study represents the first investigation of LAR in child and adolescent subjects in Latin America, contributing significantly to the understanding of its prevalence and characteristics in this geographic area. Among a subgroup of patients lacking systemic sensitization submitted to NAC, 40% (10/25) demonstrated a positive NAC with Dermatophagoides pteronyssinus and Blomia tropicalis, warranting their reclassification to LAR. NAC with multiple allergens has been proven safe and viable in pediatric populations, affirming its critical role in the accurate diagnosis of LAR.