A pathogenic integrated view explaining the different endotypes of asthma and allergic disorders

The inflammation of allergic diseases is characterized by a complex interaction between type 2 and type 3 immune responses, explaining clinical symptoms and histopathological patterns. Airborne stimuli activate the mucosal epithelium to release a number of molecules impacting the activity of resident immune and environmental cells. Signals from the mucosal barrier, regulatory cells, and the inflamed tissue are crucial conditions able to modify innate and adaptive effector cells providing the selective homing of eosinophils or neutrophils. The high plasticity of resident T- and innate lymphoid cells responding to external signals is the prerequisite to explain the multiplicity of endotypes of allergic diseases. This notion paved the way for the huge use of specific biologic drugs interfering with pathogenic mechanisms of inflammation. Based on the response of the epithelial barrier, the activity of resident regulatory cells, and functions of structural non-lymphoid environmental cells, this review proposes some immunopathogenic scenarios characterizing the principal endotypes which can be associated with a precise phenotype of asthma. Recent literature indicates that similar concepts can also be applied to the inflammation of other non-respiratory allergic disorders. The next challenges will consist in defining specific biomarker(s) of each endotype allowing for a quick diagnosis and the most effective personalized therapy.

Chronic Rhinosinusitis, S. aureus Biofilm and Secreted Products, Inflammatory Responses, and Disease Severity

Chronic rhinosinusitis (CRS) is a persistent inflammation of the nasal cavity and paranasal sinuses associated with tissue remodelling, dysfunction of the sinuses’ natural defence mechanisms, and induction of different inflammatory clusters. The etiopathogenesis of CRS remains elusive, and both environmental factors, such as bacterial biofilms and the host’s general condition, are thought to play a role. Bacterial biofilms have significant clinical relevance due to their potential to cause resistance to antimicrobial therapy and host defenses. Despite substantial medical advances, some CRS patients suffer from recalcitrant disease that is unresponsive to medical and surgical treatments. Those patients often have nasal polyps with tissue eosinophilia, S. aureus-dominant mucosal biofilm, comorbid asthma, and a severely compromised quality of life. This review aims to summarise the contemporary knowledge of inflammatory cells/pathways in CRS, the role of bacterial biofilm, and their impact on the severity of the disease. Here, an emphasis is placed on S. aureus biofilm and its secreted products. A better understanding of these factors might offer important diagnostic and therapeutic perceptions for recalcitrant disease.

Pathophysiological and Clinical Aspects of Chronic Rhinosinusitis: Current Concepts

Adult chronic rhinosinusitis (CRS) is a chronic inflammation of the mucosa of the nose and paranasal sinuses. According to the latest EPOS guidelines CRS should be regarded as primary or secondary with distinction between diffuse and localized disease. Further pathophysiologic research identified different inflammatory patterns leading to the term “endotyping of CRS.” The primary focus of endotyping is to define a dominant inflammatory type allowing for better orientation of therapy. The current approach proposes the differentiation between type 2 (eosinophilic) and non-type 2 inflammatory responses. In this review pathophysiological concepts of CRS will be discussed, focusing on the different inflammatory endotypes of T cells with special attention to the eosinophilic type 2 inflammatory response. The contribution of innate and adaptive immune system responses is presented. The possibility of endotyping based on sinonasal secretions sampling is brought to attention because it is indicative of corticosteroid responsiveness and available to most ENT surgeons. Furthermore, the clinical aspects of the three distinct phenotypes are analyzed in view of their characteristics, the related endoscopic findings, typical radiological imaging, histopathology findings, their relation toward allergy and obvious therapeutical implications. This overview will enable clinicians to relate pathophysiological patterns with clinical observations by explaining the different inflammatory mechanisms, hence providing a better understanding of therapy.

Yardstick for the medical management of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is an inflammatory condition of the paranasal sinuses defined by classic symptoms, imaging findings, or endoscopic findings. There are a growing number of emerging pharmacologic therapies being evaluated to treat patients with CRS, some of which have gained indication status in the United States. There have not been updated treatment guidelines published in the United States however since 2014. This document is meant to serve as an updated expert consensus document for the pharmacologic management of patients with CRS. We review available data focusing on prospective clinical trials on oral and intranasal corticosteroids, nasal irrigation, biologics, antibiotics, and allergy immunotherapy for CRS both with and without nasal polyposis, including specific therapies for aspirin-exacerbated respiratory disease-associated CRS and allergic fungal CRS. There are multiple options to treat CRS, and clinicians should be knowledgeable on the efficacy and risks of these available therapies. Allergists-immunologists now have various therapies available to treat patients with CRS.

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.

Manifesto on united airways diseases (UAD): an Interasma (global asthma association - GAA) document

OBJECTIVE

The large amount of evidence and the renewed interest in upper and lower airways involvement in infectious and inflammatory diseases has led Interasma (Global Asthma Association) to take a position on United Airways Diseases (UAD).

METHODS

Starting from an extensive literature review, Interasma executive committee discussed and approved this Manifesto developed by Interasma scientific network (INES) members.

RESULTS

The manifesto describes the evidence gathered to date and defines, states, advocates, and proposes issues on UAD (rhinitis, rhinosinusitis and nasal polyposis), and concomitant/comorbid lower airways disorders (asthma, chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis, obstructive sleep apnoea) with the aim of challenging assumptions, fostering commitment, and bringing about change. UAD refers to clinical pictures characterized by the coexistence of upper and lower airways involvement, driven by a common pathophysiological mechanism, leading to a greater burden on patient's health status and requiring an integrated diagnostic and therapeutic plan. The high prevalence of UAD must be taken into account. Upper and lower airways diseases influence disease control and patient's quality of life.

CONCLUSIONS

Patients with UAD need to have a timely and adequate diagnosis, treatment, and, when recommended, referral for management in a specialized center. Diagnostic testing including skin prick or serum specific IgE, lung function, fractional exhaled nitric oxide (FeNO), polysomnography, allergen-specific immunotherapies, biological therapies and home based continuous positive airway pressure (CPAP) whenever these are recommended, should be part of the management plan for UAD. Education of medical students, physicians, health professionals, patients and caregivers on the UAD is needed.

Association of Mast Cell Burden and TIM-3 Expression with Recalcitrant Chronic Rhinosinusitis with Nasal Polyps

OBJECTIVES

Previous work showed that higher polyp mast cell load correlated with worse postoperative endoscopic appearance in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Polyp epithelial mast cells showed increased expression of T-cell/transmembrane immunoglobulin and mucin domain protein 3 (TIM-3), a receptor that promotes mast cell activation and cytokine production. In this study, CRSwNP patients were followed post-operatively to investigate whether mast cell burden or TIM-3 expression among mast cells can predict recalcitrant disease.

METHODS

Nasal polyp specimens were obtained via functional endoscopic sinus surgery (FESS) and separated into epithelial and stromal layers via enzymatic digestion. Mast cells and TIM-3-expressing mast cells were identified via flow cytometry. Mann-Whitney U tests and Cox proportional hazard models assessed whether mast cell burden and TIM-3 expression were associated with clinical outcomes, including earlier recurrence of polypoid edema and need for treatment with steroids.

RESULTS

Twenty-three patients with CRSwNP were studied and followed for 6 months after undergoing FESS. Higher mast cell levels were associated with earlier recurrence of polypoid edema: epithelial HR = 1.283 (P = .02), stromal HR = 1.103 (P = .02). Percent of mast cells expressing TIM-3 in epithelial or stromal layers was not significantly associated with earlier recurrence of polypoid edema. Mast cell burden and TIM-3+ expression were not significantly associated with need for future treatment with steroids post-FESS.

CONCLUSIONS

Mast cell load in polyp epithelium and stroma may predict a more refractory postoperative course for CRSwNP patients. The role of TIM-3 in the chronic inflammatory state seen in CRSwNP remains unclear.

Topical Corticosteroids Decrease IL-25 Expression by Immunohistochemistry

BACKGROUND

Interleukin-25 (IL-25) is an important contributing factor in the pathogenesis of allergic rhinitis. It leads to increasing peripheral and infiltrating eosinophilia as well as serum IgE, IgG, and Th2 cytokines (IL-4, IL-5, IL-13), which are responsible for the allergic symptoms. Intranasal steroids (INS) are effective in treating allergic rhinitis, but their effect on IL-25 release has not been studied. We aimed to study the link between IL-25 and the pathophysiology of allergic rhinitis as well as the effect of INS on its release.

METHODOLOGY

This was a cohort, prospective, nonrandomized study that included 60 patients, 35 allergic rhinitis patients and 25 controls. We studied the effect of INS on IL-25 release.

RESULTS

Of allergic rhinitis patients 68.6% had strong cytoplasmic stain of IL-25 in the epithelial layer, while 25.7% had intermediate stain. INS caused significantly reduced IL-25 stain as only 14.3% of patients had intermediate stain and 85.7% had weak stain. Moreover, a correlation was found between nasal smear eosinophilia and the degree of IL-25 staining in the epithelial layer.

CONCLUSION

Intranasal corticosteroids appear to be effective in the downregulation of IL-25, which may explain some of the utility of intranasal corticosteroid treatment in improving allergic rhinitis symptoms.

Endotype-driven treatment in chronic upper airway diseases

Rhinitis and rhinosinusitis are the two major clinical entities of chronic upper airway disease. Chronic rhinosinusitis (CRS) and allergic rhinitis (AR) affect respectively up to 10 and 30% of the total population, hence being associated with an important socio-economic burden. Different phenotypes of rhinitis and CRS have been described based on symptom severity and duration, atopy status, level of control, comorbidities and presence or absence of nasal polyps in CRS. The underlying pathophysiological mechanisms are diverse, with different, and sometimes overlapping, endotypes being recognized. Type 2 inflammation is well characterized in both AR and CRS with nasal polyps (CRSwNP), whereas type 1 inflammation is found in infectious rhinitis and CRS without nasal polyps (CRSsNP). The neurogenic endotype has been demonstrated in some forms of non-allergic rhinitis. Epithelial barrier dysfunction is shown in AR and CRSwNP. Emerging therapies are targeting one specific pathophysiological pathway or endotype. This endotype-driven treatment approach requires careful selection of the patient population who might benefit from a specific treatment. Personalized medicine is addressing the issue of providing targeted treatment for the right patient and should be seen as one aspect of the promising trend towards precision medicine. This review provides a comprehensive overview of the current state of endotypes, biomarkers and targeted treatments in chronic inflammatory conditions of the nose and paranasal sinuses.

Effects of Fluticasone Furoate Nasal Spray on Parameters of Eosinophilic Inflammation in Patients With Nasal Polyposis and Perennial Allergic Rhinitis

OBJECTIVES

Regulated on activation normal T cell expressed and secreted (RANTES) and eotaxin-2 have been postulated to be responsible for eosinophilia in chronically inflamed nasal mucosa. This study evaluated mucosal production of RANTES and eotaxin-2 in patients with perennial allergic rhinitis (PAR) and nonallergic and allergic form of chronic rhinosinusitis with nasal polyps (CRSwNP) before and after nasal corticosteroid treatment.

METHODS

Twenty patients with PAR, 20 nonallergic and 20 allergic CRSwNP patients, and 20 healthy controls were included. The RANTES and eotaxin-2 levels were measured in nasal secretion samples. The patients with chronic inflammation were treated with fluticasone furoate nasal spray for 2 weeks. Cytological examination and measurement of RANTES and eotaxin-2 in nasal fluid were performed before and after the treatment.

RESULTS

The levels of RANTES were higher in patients with PAR ( P < .05) and nonallergic ( P < .01) and allergic CRSwNP patients ( P < .001) compared to controls. Eotaxin-2 levels were higher in all 3 inflammation groups compared to healthy subjects ( P < .001). After the treatment, we found a significant decrease of RANTES and eotaxin-2 concentrations ( P < .001) in all 3 groups of patients.

CONCLUSION

The levels of RANTES and eotaxin-2 in nasal fluid could be reliable markers for assessing corticosteroid administration outcomes.