International consensus statement on allergy and rhinology: rhinosinusitis 2021.

I. EXECUTIVE SUMMARY: BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document. METHODS: ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. RESULTS: ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided. CONCLUSION: This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Interleukin-33 activates regulatory T cells to suppress innate γδ T cell responses in the lung.

Foxp3+ regulatory T (Treg) cells expressing the interleukin (IL)-33 receptor ST2 mediate tissue repair in response to IL-33. Whether Treg cells also respond to the alarmin IL-33 to regulate specific aspects of the immune response is not known. Here we describe an unexpected function of ST2+ Treg cells in suppressing the innate immune response in the lung to environmental allergens without altering the adaptive immune response. Following allergen exposure, ST2+ Treg cells were activated by IL-33 to suppress IL-17-producing γδ T cells. ST2 signaling in Treg cells induced Ebi3, a component of the heterodimeric cytokine IL-35 that was required for Treg cell-mediated suppression of γδ T cells. This response resulted in fewer eosinophil-attracting chemokines and reduced eosinophil recruitment into the lung, which was beneficial to the host in reducing allergen-induced inflammation. Thus, we define a fundamental role for ST2+ Treg cells in the lung as a negative regulator of the early innate γδ T cell response to mucosal injury.

Phenotypes of Chronic Rhinosinusitis.

Chronic rhinosinusitis (CRS) is a complex heterogeneous disease with different phenotypes and endotypes. Recent advances in our understanding of the pathogenetic mechanisms of CRS endotypes have led to the introduction of effective biologic agents for CRS management. Traditionally, CRS phenotypes have been divided into with or without nasal polyps depending on the presence of polyps. Although this classification does not reflect the various endotypes that are recently emerging, it is simple and easily recognized by clinicians. Other phenotypes of CRS are fungal rhinosinusitis (including invasive and noninvasive subtypes), infectious rhinosinusitis, aspirin-exacerbated respiratory disease, cystic fibrosis, pediatric CRS, and CRS associated with systemic diseases. This article reviews the diagnostic approaches and up-to-date treatment strategies for each CRS phenotype with the hope that a better understanding of endotypes will result in a more scientific understanding of phenotypes and precise, personalized treatments.

Dupilumab improves health-related quality of life in patients with chronic rhinosinusitis with nasal polyposis.

BACKGROUND: Chronic rhinosinusitis with nasal polyposis (CRSwNP) negatively affects health-related quality of life (HRQoL). In a previously reported randomized clinical trial (NCT01920893), addition of dupilumab to mometasone furoate in patients with CRSwNP refractory to intranasal corticosteroids (INCS) significantly improved endoscopic, radiographic, and clinical endpoints and patient-reported outcomes. The objective of this analysis was to examine the impact of dupilumab treatment on HRQoL and productivity using secondary outcome data from this trial. METHODS: Following a 4-week mometasone furoate nasal spray run-in, patients were randomized to commence subcutaneous dupilumab (600 mg loading dose, then 300 mg once weekly for 15 weeks [n = 30], or matched placebo [n = 30]). Outcomes included scores on the CRS disease severity visual analog scale (VAS), 22-item Sino-Nasal Outcome Test (SNOT-22), 5-dimension EuroQoL (EQ-5D) general health status VAS, and 36-item Short-Form Health Survey (SF-36) for HRQoL and nasal polyp-related healthcare resource use questionnaires. RESULTS: Following 16 weeks of treatment, the proportion of patients with moderate-to-severe CRSwNP (VAS > 3-10) decreased from 86.2% to 21.4% with dupilumab and 88.0% to 84.2% with placebo. Dupilumab (vs placebo) resulted in significantly greater improvement in HRQoL, based on SNOT-22, SF-36, and EQ-5D VAS scores. The dupilumab group had a significantly lower adjusted annualized mean number of sick leave days (0.09, vs 4.18 with placebo, P = .015) and significantly greater improvement (vs placebo) in the SNOT-22 item "reduced productivity." CONCLUSIONS: In adults with CRSwNP refractory to treatment with INCS alone, the addition of dupilumab reduced disease severity, significantly improved HRQoL, and improved productivity.

Novel CARD9 mutation in a patient with chronic invasive dermatophyte infection (tinea profunda).

Caspase Recruitment Domain Family Member 9 (CARD9) is an adaptor molecule that drives antifungal activity of macrophages and neutrophils in the skin. Autosomal recessive loss-of-function mutations in CARD9 confer increased susceptibility to invasive disease with select fungi in non-immunosuppressed patients. We report on a patient with X-linked ichthyosis complicated by chronic cutaneous invasive dermatophyte infection. We identified a previously reported c.271T>C (p.Y91H) mutation and a novel intronic c.1269+18G>A mutation in CARD9 underlying recurrent deep dermatophytosis in this patient despite various antifungals for over three decades. Our case highlights susceptibility to invasive dermatophytosis related to autosomal recessive CARD9 deficiency and illustrates the range of CARD9 mutations to be pursued in immunocompetent patients with unexplained deep dermatophyte infections. Further studies are needed to define the best therapeutic regimen.

Dupilumab reduces opacification across all sinuses and related symptoms in patients with CRSwNP.

BACKGROUND: Chronic rhinosinusitis with nasal polyposis (CRSwNP) is associated with substantial sinus opacification. In a phase 2a study (NCT01920893), dupilumab, a fully human anti-IL-4Rα monoclonal antibody, improved outcomes in CRSwNP refractory to intranasal corticosteroids. We evaluated dupilumab’s effect on sinus opacification in relation to effects on nasal polyp burden, symptoms, and health-related quality of life (HRQoL) in patients with CRSwNP. METHODOLOGY: 16-week randomized, double-blind, placebo-controlled, parallel-group study in 60 adults with CRSwNP. Patients received weekly subcutaneous dupilumab 300-mg or placebo and daily mometasone furoate nasal spray. Sinus opacification was assessed using standard and Zinreich-modified Lundâ€"Mackay (zLMK) scoring. Correlation was assessed between zLMK score and CRSwNP endpoints, including nasal polyp score (NPS), SNOT-22, daily symptom scores, and UPSIT smell-test score. RESULTS: Baseline characteristics were similar across treatment groups. Mean plus/minus SD baseline LMK scores of 18.7 plus/minus 5.5 (placebo) and 18.6 plus/minus 5.0 (dupilumab) indicated severe disease with extensive opacification involving all sinuses. Baseline LMK and LMK scores correlated with NPS severity and loss of sense of smell (daily symptoms; SNOT-22 smell/taste; loss of sense of smell [UPSIT]). At Week 16, dupilumab-treated patients had significantly improved sinus opacification measured by LMK in all individual sinuses vs placebo. Dupilumab also showed similar efficacy with zLMK, with only small differences from LMK, and correlated with SNOT22 smell/taste. The most common adverse events were nasopharyngitis, injection-site reactions, and headache. CONCLUSIONS: In patients with CRSwNP, baseline LMK showed extensive sinus opacification and correlated with symptoms, HRQoL, and hyposmia. Dupilumab treatment reduces opacification across all sinuses and related symptoms in patients with CRSwNP.

Biofilm Formations in Pediatric Respiratory Tract Infection Part 2: Mucosal Biofilm Formation by Respiratory Pathogens and Current and Future Therapeutic Strategies to Inhibit Biofilm Formation or Eradicate Established Biofilm.

PURPOSE OF REVIEW: The purpose of this review is to discuss the unique pathways of biofilm formation utilized by respiratory pathogens and current and future therapeutic strategies to inhibit biofilm formation or eradicate established biofilm in the context of these pathogens. Both nonselective and selective strategies for inhibiting biofilm formation or disrupting established biofilm are discussed. RECENT FINDINGS: Numerous strategies are being actively pursued to inhibit biofilm formation or eradicate established biofilm in respiratory pathogens. These can be broadly categorized by the stage of biofilm formation (adhesion, extracellular polysaccharide synthesis or structure, EPS, and matrix degradation) that they target and by their selectivity or lack thereof for specific biofilm pathogens. Nonselective inhibitors of adhesion include N-acetylcysteine and artificial surfactants and biosurfactants. Selective inhibitors of adhesion include mannosides that target host-EPS interactions, EPS-targeted antibodies, and other inhibitors of bacterial adhesion. Nonselective inhibitors of EPS synthesis and structure include cyclic di-GMP and cyclic di-AMP-through disruption of glucan-producing exoenzymes. Selective inhibitors of EPS synthesis and structure include antibodies that target proteins essential for biofilm structure (such as DNABII proteins and type IV pilin protein in NTHi) or antibodies that target critical molecules in biofilm formation (such as DNA adenine methyltransferase in Streptococcus pneumoniae). Nonselective agents for EPS or biofilm matrix degradation include peptidoglycan hydrolases that enzymatically degrade bacterial cell wall peptidoglycan and DNase, which degrades extracellular DNA from neutrophils and microorganism-derived DNA. Selective agents for EPS or biofilm matrix degradation include exopolysaccharide-degrading enzymes, such as glycoside hydrolases active against Staphylococcus aureus or exopolysaccharide-degrading enzymes that target Psl and Pel from Pseudomonas aeruginosa. Current strategies toward inhibiting biofilm formation or disrupting established biofilm represent an exciting new approach toward treatment of chronic infectious diseases. Application of these strategies toward treatment of pediatric respiratory tract infections also offers promise of a better understanding of the significance of mucosal biofilm in the pathogenesis of these conditions.

Quantitative assessment of airway remodelling and response to allergen in asthma.

BACKGROUND AND OBJECTIVE: In vivo evaluation of the microstructural differences between asthmatic and non-asthmatic airways and their functional consequences is relevant to understanding and, potentially, treating asthma. In this study, we use endobronchial optical coherence tomography to investigate how allergic airways with asthma differ from allergic non-asthmatic airways in baseline microstructure and in response to allergen challenge. METHODS: A total of 45 subjects completed the study, including 20 allergic, mildly asthmatic individuals, 22 non-asthmatic allergic controls and 3 healthy controls. A 3-cm airway segment in the right middle and right upper lobe were imaged in each subject immediately before and 24 h following segmental allergen challenge to the right middle lobe. Relationships between optical airway measurements (epithelial and mucosal thicknesses, mucosal buckling and mucus) and airway obstruction (FEV1 /FVC (forced expiratory volume in 1 s/forced vital capacity) and FEV1 % (FEV1 as a percentage of predictive value)) were investigated. RESULTS: Significant increases at baseline and in response to allergen were observed for all four of our imaging metrics in the asthmatic airways compared to the non-asthmatic airways. Epithelial thickness and mucosal buckling exhibited a significant relationship to FEV1 /FVC in the asthmatic group. CONCLUSION: Simultaneous assessments of airway microstructure, buckling and mucus revealed both structural and functional differences between the mildly asthmatic and control groups, with airway buckling seeming to be the most relevant factor. The results of this study demonstrate that a comprehensive, microstructural approach to assessing the airways may be important in future asthma studies as well as in the monitoring and treatment of asthma.

Biofilm Formations in Pediatric Respiratory Tract Infection : Part 1: Biofilm Structure, Role of Innate Immunity in Protection Against and Response to Biofilm, Methods of Biofilm Detection, Pediatric Respiratory Tract Diseases Associated with Mucosal Biofilm Formation.

PURPOSE OF REVIEW: Biofilm represents an organized structure of microorganisms within an extracellular matrix attached to a surface. While the importance of biofilm in prosthetic heart valve and catheter-related infections has been known since the 1980s, the role of mucosal biofilm in human disease pathogenesis has only recently been elucidated. It is now clear that mucosal biofilm is present in both healthy and pathologic states. The purpose of this review is to examine the role of mucosal biofilm in pediatric respiratory infections. RECENT FINDINGS: Mucosal biofilm has been implicated in relationship to several pediatric respiratory infections, including tonsillitis, adenoiditis, otitis media with effusion, chronic rhinosinusitis, persistent endobronchial infection, and bronchiectasis. In these conditions, core pathogens are detected in the biofilm, biofilm organisms are often detected by molecular techniques when conventional cultures are negative, and biofilm presence is more extensive in relation to disease than in healthy tissues. In chronic rhinosinusitis, the presence of polymicrobial biofilm is also a predictor of poorer outcome following sinus surgery. Biofilm in the tonsillar and adenoidal compartments plays a distinct role in contributing to disease in the middle ear and sinuses. Key observations regarding the relevance of biofilm to pediatric respiratory infections include (1) the association between the presence of biofilm and persistent/recurrent and more severe disease in these tissues despite antibiotic treatment, (2) linkage between biofilm core pathogens and acute infections, and (3) interrelationship between biofilm presence in one tissue and persistent or recurrent infection in an adjacent tissue. A greater understanding of the significance of mucosal biofilm will undoubtedly emerge with the development of effective means of eradicating mucosal biofilm.

Automated segmentation and quantification of airway mucus with endobronchial optical coherence tomography.

We propose a novel suite of algorithms for automatically segmenting the airway lumen and mucus in endobronchial optical coherence tomography (OCT) data sets, as well as a novel approach for quantifying the contents of the mucus. Mucus and lumen were segmented using a robust, multi-stage algorithm that requires only minimal input regarding sheath geometry. The algorithm performance was highly accurate in a wide range of airway and noise conditions. Mucus was classified using mean backscattering intensity and grey level co-occurrence matrix (GLCM) statistics. We evaluated our techniques in vivo in asthmatic and non-asthmatic volunteers.

Recent advances in understanding and managing IgG4-related disease.

IgG4-related disease was only recently discovered, so its description, management, and new discoveries related to its etiology are rapidly evolving. Because IgG4 itself is a unique antibody which is intimately related to the diagnosis of the disease, the role of plasmablasts in the pathophysiology remains an active area of discussion. Recent studies have uncovered a possible role for CD4-positive cytotoxic T lymphocytes, T follicular helper cells, and M2 macrophages. The clinical presentation is variable and can be vague, as this disease affects many organs and new presentations are continuing to be described. The diagnosis depends on clinical and histopathological assessment. The mainstay of treatment is with glucocorticoids, but rituximab has recently shown promise. Monitoring disease activity using imaging modalities (including positron emission tomography) and serum markers is imperative, as relapses are common. IgG4-related disease spans many medical disciplines but is a treatable condition with which all clinicians should be familiar.

Birefringence microscopy platform for assessing airway smooth muscle structure and function in vivo.

The inability to visualize airway smooth muscle (ASM) cells in vivo is a major obstacle in understanding their role in normal physiology and diseases. At present, there is no imaging modality available to assess ASM in vivo. Confocal endomicroscopy lacks the penetration depth and field of view, and conventional optical coherence tomography (OCT) does not have sufficient contrast to differentiate ASM from surrounding tissues. We have developed a birefringence microscopy platform that leverages the micro-organization of tissue to add further dimension to traditional OCT. We have used this technology to validate ASM measurements in ex vivo swine and canine studies, visualize and characterize volumetric representations of ASM in vivo, and quantify and predict ASM contractile force as a function of optical retardation. We provide in vivo images and volumetric assessments of ASM in living humans and document structural disease variations in subjects with mild asthma. The opportunity to link inflammatory responses to ASM responses and to link ASM responses to clinical responses and outcomes could lead to an increased understanding of diseases of the airway and, ultimately, to improved patient outcomes.

Allergic asthma is distinguished by sensitivity of allergen-specific CD4+ T cells and airway structural cells to type 2 inflammation.

Despite systemic sensitization, not all allergic individuals develop asthma symptoms upon airborne allergen exposure. Determination of the factors that lead to the asthma phenotype in allergic individuals could guide treatment and identify novel therapeutic targets. We used segmental allergen challenge of allergic asthmatics (AA) and allergic nonasthmatic controls (AC) to determine whether there are differences in the airway immune response or airway structural cells that could drive the development of asthma. Both groups developed prominent allergic airway inflammation in response to allergen. However, asthmatic subjects had markedly higher levels of innate type 2 receptors on allergen-specific CD4+ T cells recruited into the airway. There were also increased levels of type 2 cytokines, increased total mucin, and increased mucin MUC5AC in response to allergen in the airways of AA subjects. Furthermore, type 2 cytokine levels correlated with the mucin response in AA but not AC subjects, suggesting differences in the airway epithelial response to inflammation. Finally, AA subjects had increased airway smooth muscle mass at baseline measured in vivo using novel orientation-resolved optical coherence tomography. Our data demonstrate that the development of allergic asthma is dependent on the responsiveness of allergen-specific CD4+ T cells to innate type 2 mediators as well as increased sensitivity of airway epithelial cells and smooth muscle to type 2 inflammation.

Chronic Rhinosinusitis in Patients with Cystic Fibrosis.

Chronic rhinosinusitis (CRS) is highly prevalent in patients with cystic fibrosis (CF) and accounts for significant morbidity and contribution to CF lung disease. Mutations of the cystic fibrosis transmembrane regulator gene occur with increased prevalence in patients with CRS without CF, suggesting some contribution to CRS pathophysiology. Nasal polyps (NPs) occur with increased prevalence in patients with CF of all ages and have a more neutrophilic appearance with fewer eosinophils and increased submucosal glandular elements in comparison to NPs from patients without CF. Mainstays of medical treatment include isotonic saline irrigations and topical intranasal glucocorticoids, with some evidence that topical intranasal glucocorticoids reduce NP size. Although inhaled hypertonic saline (7%) has been widely studied as a mucolytic agent for CF lung disease, there are no reports of its use in CF CRS. Mucolytics have also not been studied as a treatment for CRS in CF, and most evidence does not support their use for CF lung disease. Nasally nebulized dornase alfa (recombinant human deoxyribonuclease) following sinus surgery shows promise for treatment. Other unproven therapies include addition of baby shampoo to isotonic saline to potentially thin mucus and help prevent biofilm formation. There are no data to support the use of low-dose oral macrolide antibiotics or the use of prophylactic oral antibiotics for CRS in patients with CF. However, there is some support for the use of topical antibiotics, including colistimethate sodium or tobramycin, administered as a sinus irrigation or antral lavage in patients following sinus surgery when susceptible bacteria are cultured. Key components of CF sinus surgical management include extensive surgery to ensure that the maxillary, frontal, sphenoid, and ethmoid sinuses are all widely opened with smoothing of bony overhangs to prevent mucus retention and bacterial recolonization, postoperative meticulous daily nasal irrigations, and appropriate use of culture-directed topical antibiotics. There are no data yet on whether CF-targeted therapies, including ivacaftor or ivacaftor combined with lumacaftor, have an impact on CF CRS.

Problem-based learning discussion: Medical treatment of pediatric chronic rhinosinusitis.

This problem-based learning case focused on the approach to evaluation and management of a 5-year old girl who was "always sick" with sinus infections. The discussion unfolds in a "real life" scenario, i.e., based on information available to the clinician initially and after the acquisition of laboratory data, and, ultimately, after sinus surgery. Emphasis is placed on the differential diagnosis of the patient's symptoms, discussion of the initial management strategy for chronic rhinosinusitis (CRS), evolution from acute rhinosinusitis to CRS, the prevalence of and differential diagnosis of nasal polyps in children, treatment considerations specific for CRS with nasal polyps, the significance of Pseudomonas aeruginosa sinus infection, the significance of an abnormal sweat chloride test in a young child with nasal polyposis, special considerations in children with CRS who have cystic fibrosis, treatment considerations after endoscopic sinus surgery, and, finally, prognostic factors that impact the outcomes of endoscopic sinus surgery. This problem-based learning case highlights many facets of managing refractory CRS in children.

International Consensus Statement on Allergy and Rhinology: Rhinosinusitis.

BACKGROUND: The body of knowledge regarding rhinosinusitis(RS) continues to expand, with rapid growth in number of publications, yet substantial variability in the quality of those presentations. In an effort to both consolidate and critically appraise this information, rhinologic experts from around the world have produced the International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR:RS). METHODS: Evidence-based reviews with recommendations(EBRRs) were developed for scores of topics, using previously reported methodology. Where existing evidence was insufficient for an EBRR, an evidence-based review (EBR)was produced. The sections were then synthesized and the entire manuscript was then reviewed by all authors for consensus. RESULTS: The resulting ICAR:RS document addresses multiple topics in RS, including acute RS (ARS), chronic RS (CRS)with and without nasal polyps (CRSwNP and CRSsNP), recurrent acute RS (RARS), acute exacerbation of CRS (AECRS), and pediatric RS. CONCLUSION: As a critical review of the RS literature, ICAR:RS provides a thorough review of pathophysiology and evidence-based recommendations for medical and surgical treatment. It also demonstrates the significant gaps in our understanding of the pathophysiology and optimal management of RS. Too often the foundation upon which these recommendations are based is comprised of lower level evidence. It is our hope that this summary of the evidence in RS will point out where additional research efforts may be directed.