Neutrophil infiltrates and eosinophil aggregates in chronic rhinosinusitis with nasal polyps and EGPA

When the Nose Meets the Lab: Histopathological Analysis in Chronic Rhinosinusitis with Nasal Polyps for Routine Clinical Practice

PURPOSE OF REVIEW

We aimed to review the latest evidence regarding the value of tissue histopathological analysis in chronic rhinosinusitis with nasal polyps (CRSwNP) and to facilitate tissue analysis by proposing a pragmatic checklist for clinical settings.

RECENT FINDINGS

CRSwNP is a chronic inflammatory disease that severely impairs the patient's quality of life. The severity of the disease can be correlated with nasal polyps enriched in eosinophils/IL-5 and, although ≥ 10 eosinophils per high power field are considered enough to determine an eosinophilic CRS, this cut-off value, the biopsy method, and the sampling location are still a matter of debate. Besides, tissue eosinophil values might also have some added value when combined with other cellular counts (e.g., eosinophil-to-lymphocyte ratio, Charcot-Leyden crystals). Structured histopathology analysis of sinonasal tissue-including, for instance, tissue remodelling biomarkers, fibrosis, and eosinophilic aggregates-has proven to be a valuable tool for healthcare professionals to identify different pheno-endotypes of CRSwNP and to improve the prioritisation of candidates to targeted therapies. Patients with CRSwNP are treated according to their severity with corticosteroids (intranasal and systemic), endoscopic sinus surgery, and/or biological therapy. A panel of expert ear, nose, and throat specialists and pathologists proposed a pragmatic checklist to improve the clinical practice around tissue analysis in CRSwNP, to facilitate communication between hospital-based healthcare professionals, and to standardize the evaluation of inflammatory biomarkers.

Three cases of relapsed eosinophilic sinusitis without eosinophilia during mepolizumab maintenance therapy for eosinophilic granulomatosis with polyangiitis

We present three cases of eosinophilic granulomatosis with polyangiitis (EGPA) where patients experienced relapse of eosinophilic sinusitis without peripheral eosinophilia while on remission maintenance therapy with mepolizumab (MPZ), an anti-interleukin (IL)-5 monoclonal antibody. Despite the initial control of symptoms with high-dose prednisolone (PSL) and MPZ, patients experienced a relapse of nasal obstruction and eosinophilic infiltration in nasal mucosal biopsies. Notably, relapses occurred despite normal peripheral eosinophil counts, indicating the localized nature of eosinophilic inflammation. While IL-5 inhibitors effectively reduce peripheral blood eosinophils, eosinophilic sinusitis may persist due to local factors such as IL-4-mediated inflammation. IL-4 has been implicated in promoting eosinophil migration into nasal tissues, suggesting that IL-5 inhibitors alone may not sufficiently suppress eosinophilic infiltration in such cases. These findings highlight the importance of considering the possibility of eosinophilic sinusitis relapse in EGPA patients treated with IL-5 inhibitors and reduced glucocorticoid doses. Further research is warranted to elucidate the mechanisms underlying local eosinophilic inflammation and optimize treatment strategies for EGPA patients.

Non-Type 2 and Mixed Inflammation in Chronic Rhinosinusitis and Lower Airway Disease

OBJECTIVE

The aim was to discuss the role of non-type 2 inflammation in patients diagnosed with chronic rhinosinusitis (CRS) and comorbid lower airway disease.

DATA SOURCES

Medline, Embase, National Institute for Health and Care Excellence, TRIP Database, ProQuest, Clinicaltrials.gov, Cochrane Central Registry of Controlled Trials, Web of Science, government and health organizations, and graduate-level theses.

REVIEW METHODS

This scoping review followed PRISMA-ScR guidelines. Search strategy was peer-reviewed by medical librarians. Studies were included if they utilized airway sampling, non-type 2 cytokines, and patients with CRS and lower airway disease.

RESULTS

Twenty-seven from 7060 articles were included. In patients with CRS and comorbid asthma, aspirin-exacerbated respiratory disease (AERD), and chronic obstructive pulmonary disease (COPD)/bronchiectasis, 60% (n = 12), 33% (n = 2), and 100% (n = 1), respectively, demonstrated mixed or non-type 2 endotypes. Comorbid CRS and asthma produced type 1 (n = 1.5), type 2 (n = 8), type 3 (n = 1), mixed type 1/2 (n = 1), and mixed type 1/2/3 (n = 8.5) endotype shifts. AERD demonstrated type 2 (n = 4), mixed type 2/3 (n = 1), and mixed type 1/2/3 (n = 1) endotype shifts. CRS with COPD or bronchiectasis demonstrated a mixed 1/2 (n = 1) endotype shift.

CONCLUSION

Type 2 disease has been extensively reviewed due to advent biologics targeting type 2 inflammation, but outcomes may be suboptimal due to the presence of non-type 2 inflammation. A proportion of patients with CRS and comorbid lower airway disease demonstrated mixed and non-type 2 endotype shifts. This emphasizes that patients with unified airway disease may have forms of inflammation beyond classical type 2 disease which could inform biologic development. Laryngoscope, 134:1005-1013, 2024.

Evidence-Based Guideline for the diagnosis and management of eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, characterized by asthma, eosinophilia and granulomatous or vasculitic involvement of several organs. The diagnosis and management of EGPA are often challenging and require an integrated, multidisciplinary approach. Current practice relies on recommendations and guidelines addressing the management of ANCA-associated vasculitis and not specifically developed for EGPA. Here, we present evidence-based, cross-discipline guidelines for the diagnosis and management of EGPA that reflect the substantial advances that have been made in the past few years in understanding the pathogenesis, clinical subphenotypes and differential diagnosis of the disease, as well as the availability of new treatment options. Developed by a panel of European experts on the basis of literature reviews and, where appropriate, expert opinion, the 16 statements and five overarching principles cover the diagnosis and staging, treatment, outcome and follow-up of EGPA. These recommendations are primarily intended to be used by healthcare professionals, pharmaceutical industries and drug regulatory authorities, to guide clinical practice and decision-making in EGPA. These guidelines are not intended to limit access to medications by healthcare agencies, nor to impose a fixed order on medication use.

Autoimmunity: A New Focus on Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) has long been considered a benign, chronic inflammatory, and hyperplastic disease. Recent studies have shown that autoimmune-related mechanisms are involved in the pathology of nasal polyps. Activated plasma cells, eosinophils, basophils, innate type 2 lymphocytes, mast cells, and proinflammatory cytokine in polyp tissue indicate the mobilization of innate and adaptive immune pathways during polyp formation. The discovery of a series of autoantibodies further supports the autoimmune nature of nasal polyps. Local homeostasis dysregulation, infection, and chronic inflammation may trigger autoimmunity through several mechanisms, including autoantigens overproduction, microbial translocation, molecular mimicry, superantigens, activation or inhibition of receptors, bystander activation, dysregulation of Toll-Like Receptors (TLRs), epitope spreading, autoantigens complementarity. In this paper, we elaborated on the microbiome-mediated mechanism, abnormal host immunity, and genetic changes to update the role of autoimmunity in the pathogenesis of chronic rhinosinusitis with nasal polyps.

Neutrophilic inflammation in chronic rhinosinusitis

PURPOSE OF REVIEW

Over the last years, extensive research has been done on neutrophils and their contribution in chronic rhinosinusitis (CRS), and made it clear that they are more than just a bystander in this disease. In this article, we will review all recent publications on this topic and look to what the future hold regarding therapeutics targeting the neutrophilic inflammation in CRS.

RECENT FINDINGS

Evidence is growing that the presence of neutrophils are associated with a worse disease outcome in certain CRS patient groups. They are highly activated in type 2 inflammations and exhibit damaging properties through their proteases, contributing to the chronicity of the disease. Several recent studies identified useful biomarkers and targets for future therapeutics.

SUMMARY

The findings we review in this manuscript are of utmost importance in unraveling the complexity of CRS and provide us with the necessary knowledge for future clinical practices.

Odontogenic Chronic Rhinosinusitis: Structured Histopathology Evidence in Different Patho-Physiological Mechanisms

An increased odontogenic chronic rhinosinusitis (oCRS) occurrence rate has quite recently been reported, likely due to an intensification of conservative dental surgery and implantology. The main aim of the study was to report for the first time the structured histopathological characteristics of the surgical specimens of oCRS. Possible associations between histopathological features and oCRS patho-physiological mechanisms were also evaluated. Structured histopathology features were investigated in the sinonasal mucosa tissue of 42 consecutive oCRS patients.Mean tissue eosinophil counts were significantly different between oCRS with radicular cysts, dental implants, or other dental diseases (p =0.0118): mean tissue eosinophil count was higher in oCRS with dental implants. Sub-epithelial edema score and squamous metaplasia presence were significantly different when comparing the above-mentioned sub-cohorts of oCRS (p =0.0099 and p =0.0258). In particular, squamous metaplasia was more present in oCRS cases with radicular cysts than in those with a dental implant (p =0.0423). Fibrosis presence was significantly different comparing the three sub-cohorts of oCRS (p =0.0408), too. This preliminary evidence supports the hypothesis that: (i) structural histopathology can become a useful tool for clinic-pathological practice in diagnostic, therapeutic, and prognostic terms in CRS; (ii) that oCRS, as CRS in general, is a histo-pathologically heterogeneous disease; (iii) oCRS resulting from dental implants disorders can frequently be characterized as a CRS with a rich tissue eosinophilic component.

Endotyping of nasal polyps in a multiracial Asian population

Background: Chronic rhinosinusitis is a heterogenous disease with variation in the endotypes of nasal polyps, with type 2 inflammation being more prevalent in Caucasian populations whereas Chinese populations are more heterogenous. We aim to describe the variation in endotypes for patients with chronic rhinosinusitis with nasal polyposis in our unique multiracial population. Methodology: Demographic, clinical and structured histopathological data of 66 patients who underwent sinus surgery for nasal polyposis were evaluated retrospectively. Results: 54.6% had eosinophilic disease, and 45.4% had non-eosinophilic disease with no significant demographic differences between the 2 populations. There were significantly higher peripheral eosinophil levels in patients with eosinophil-predominant inflammation on tissue histology (mean absolute eosinophil count 0.59 ± 0.18 x 109) compared with non-eosinophilic disease (mean absolute eosinophil count 0.24 ± 0.11 x 109). Structured histopathological reporting revealed that patients with eosinophilic disease had higher degree of inflammation and eosinophil aggregates. Conclusions: Our population is shown to have a slight preponderance toward eosinophilic disease, however the Chinese majority tended to have non-eosinophilic disease. Serum eosinophilia and the presence of asthma seems to correlate well with tissue eosinophilia, which can potentially be utilised as markers of type 2 inflammatory disease.

Structured histopathology for endotyping and planning rational treatment in chronic rhinosinusitis

In chronic rhinosinusitis (CRS), endotyping, being based on the pathogenic mechanism, provides a precise picture appropriate for use in clinical practice. Structured histopathological examination of CRS is considered a necessary step in efforts to establish its pathogenesis and improve our endotyping capabilities. Herein we discuss the associations between histopathology and clinical characteristics of CRS patients to assist medical and surgical treatment choices.