Exploring the role of nasal cytology in chronic rhinosinusitis

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.

Type 2 Biomarkers for the Indication and Response to Biologics in CRSwNP

PURPOSE OF REVIEW

Three biologics targeting type 2 inflammation have been approved for the treatment of severe and uncontrolled chronic rhinosinusitis with nasal polyps (CRSwNP). Nevertheless, around 40-60% of patients do not respond well to these biological treatments. Selecting appropriate patients is crucial to improve treatment outcome of biologics. This review summarizes the literature data on type 2 biomarkers, with a specific focus on the indication to biologics for severe CRSwNP.

RECENT FINDINGS

No consensus has been reached on how to define mucosal type 2 inflammation in CRSwNP. Clinical markers (e.g., 22-item Sino-nasal Outcome Test (SNOT-22) score, Lund-Mackay CT score (LMS), ethmoid/maxillary sinus CT score, and CT-radiomics), nasal secretion biomarkers (e.g., eosinophil cationic protein and interleukin-5), blood and nasal cytology eosinophil counts, and nasal swab eosinophil peroxidase activity have been reported to be associated with type 2 inflammation in CRSwNP. The time duration since the last surgery, SNOT-22 score at 1 week of treatment, and baseline serum osteoprotegerin levels might indicate the response to dupilumab. LMS and asthma control test scores were found to have moderate predictive value for acceptable improvement after 24-week treatment of omalizumab. High blood eosinophil levels at baseline were associated with treatment response to mepolizumab and benralizumab. Although several clinical and biological markers might be associated with type 2 inflammation and response to biologics in patients with CRSwNP, their validity requires further investigation. Identifying clinically applicable biomarkers for biologic treatment holds significant promise for advancing personalized approaches to biologics and optimizing treatment outcomes for patients with CRSwNP.

An eosinophil peroxidase activity assay accurately predicts eosinophilic chronic rhinosinusitis

BACKGROUND

A definitive diagnosis of eosinophilic chronic rhinosinusitis (eCRS) requires invasive surgical tissue sampling and histologic enumeration of intact eosinophils. Eosinophil peroxidase (EPX) is an accurate biomarker of sinonasal tissue eosinophilia in CRS regardless of polyp status. A less invasive and rapid method that accurately identifies tissue eosinophilia would be of great benefit to patients.

OBJECTIVE

We sought to evaluate a new clinical tool that uses a nasal swab and colorimetric EPX activity assay to predict a diagnosis of eCRS.

METHODS

A prospective, observational cohort study was conducted using nasal swabs and sinonasal tissue biopsies obtained from patients with CRS electing endoscopic sinus surgery. Patients were classified as non-eCRS (n = 19) and eCRS (n = 35) on the basis of pathologically determined eosinophil counts of less than 10 or greater than or equal to 10 eosinophils/HPF, respectively. Swab-deposited EPX activity was measured and compared with tissue eosinophil counts, EPX levels, and CRS-specific disease metrics.

RESULTS

EPX activity was significantly increased in patients with eCRS than in patients without eCRS (P < .0001). With a relative absorbance unit cutoff value of greater than or equal to 0.80, the assay demonstrated high sensitivity (85.7%) and moderate specificity (79.0%) for confirming eCRS. Spearman correlations between EPX activity and tissue eosinophil counts (rs = 0.424), EPX levels (rs = 0.503), and Lund-Kennedy endoscopy scores (rs = 0.440) in eCRS were significant (P < .05).

CONCLUSIONS

This investigation evaluates a nasal swab sampling method and EPX activity assay that accurately confirms eCRS. This method could potentially address the unmet need to identify sinonasal tissue eosinophilia at the point-of-care, as well as to longitudinally monitor eosinophil activity and treatment response.

Middle meatus nasal cytology compared to inferior turbinate cytology in non allergic rhinitis

PURPOSE

Non allergic rhinitis (NAR) comprises different clinical definitions and phenotypes, including non inflammatory non allergic (NINAR) and cellular inflammatory forms. Nasal cytology, usually performed by scraping the inferior turbinate, is a non invasive, cheap and point-of-care tool to distinguish among the different NAR phenotypes, but still a relevant proportion of patients evaluated by nasal cytology receive a non precise definition of NAR phenotype. We hypothesize that collecting nasal cytology samples from middle meatus could increase the diagnostic accuracy.

METHODS

Consecutive patients with chronic rhinitis without evidence of allergic sensitization were assessed for nasal cytology by means of scraping both the inferior turbinate and the middle meatus (lateral-inferior wall of the middle turbinate).

RESULTS

107 consecutive patients with NAR were enrolled in the study. According to inferior turbinate cytology, 42.1% were defined as affected by NINAR, 2.8% by bacterial rhinitis, 10.3% by non allergic rhinitis with eosinophils (NARES), 15.0% non allergic rhinitis with neutrophils (NARNE), 19.6% non allergic rhinitis with mast-cells (NARMA) and 10.3% non allergic rhinitis with eosinophils and mast-cells (NARESMA). Middle meatus cytology was in accordance with inferior turbinate cytology in only 37.6% of cases. Eosinophils and mast-cells were detectable more frequently in middle meatus samples (49.5% vs 19.6%, p < 0.01, 59.8% vs 29.9%, p < 0.01, respectively). 93.3% of NINAR patients received an inflammatory NAR phenotype at middle meatus cytology: 26.7% NARES, 24.4% NARNE, 31.1% NARMA and 11.1% NARESMA.

CONCLUSION

Middle meatus cytology is more reliable than inferior turbinate cytology in phenotyping patients with NAR. Our study strengthen that nasal cytology should be implemented in clinical practice collecting samples at the middle meatus level.

Chronic Rhinosinusitis: T2r38 Genotyping and Nasal Cytology in Primary Ciliary Dyskinesia

OBJECTIVES

Chronic rhinosinusitis (CRS) is a major hallmark of primary ciliary dyskinesia (PCD). We investigated the possible correlation between some severity markers of CRS and several clinical features of the disease. We further studied the bitter taste receptor TAS2R38 polymorphisms to identify the genotypes associated with more severe disease.

METHODS

We included 39 adult PCD patients with (CRSwNP) and without nasal polyposis (CRSsNP); a sample for nasal cytology was obtained and clinical cytological grading (CCG) was determined. The SNOT-22 and Lund-Mackay scores were recorded. A sample of DNA was extracted from peripheral blood to investigate TAS2R38 polymorphisms.

RESULTS

CRSwNP patients had features of more severe disease: indeed, they had statistically significantly higher frequency of previous sinus surgery, higher SNOT-22, LM scores, and CCG than CRSsNP patients. Upon genotyping of TAS2R38 polymorphisms, we observed that the AVI-AVI genotype, associated to homozygous nonfunctional bitter TAS2R38 receptor, was more prevalent among CRSwNP (100%) than in CRSsNP patients (0%); furthermore, AVI-AVI subjects showed statistically significantly worse SNOT-22 and CCG scores than PAV-PAV and PAV-AVI subjects. The group of AVI-AVI patients also had more frequent respiratory exacerbations, Gram-negative infections, and Pseudomonas aeruginosa colonization than PAV-PAV and PAV-AVI patients.

CONCLUSION

Our findings indicate for the first time that PCD patients with CRSwNP display a more severe disease than those with CRSsNP. Genotyping of TAS2R38 polymorphisms demonstrated that in PCD patients, the AVI-AVI genotype is strikingly more prevalent among CRSwNP than in CRSsNP, while the PAV-PAV genotype might be protective against Gram-negative infections and respiratory exacerbations.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:248-254, 2023.

Differential nasal swab cytology represents a valuable tool for therapy monitoring but not prediction of therapy response in chronic rhinosinusitis with nasal polyps treated with Dupilumab

Introduction

Chronic Rhinosinusitis with nasal polyps (CRSwNP) is a common chronic disease with a high impact on patients' quality of life. If conservative and surgical guideline treatment cannot sufficiently control disease burden, biologicals can be considered as a comparably new treatment option that has revolutionized CRSwNP therapy since the first approval of Dupilumab in 2019. With the aim to select patients who benefit from this new treatment and to find a marker for therapy monitoring, we investigated the cellular composition of nasal mucous membranes and inflammatory cells of patients suffering from CRSwNP and undergoing Dupilumab therapy using non-invasive nasal swab cytology.

Methods

Twenty CRSwNP patients with the indication for Dupilumab therapy have been included in this prospective clinical study. In total, five study visits were conducted with ambulatory nasal differential cytology using nasal swabs starting with the beginning of therapy and followed by visits every 3 months for 12 months. First, these cytology samples were stained with the May-Grunwald-Giemsa method (MGG) and the percentage of ciliated cells, mucinous cells, eosinophil cells, neutrophil cells, and lymphocytes was analyzed. Secondly, an immunocytochemical (ICC) ECP-staining was performed to detect eosinophil granulocytes. Additionally, during each study visit the nasal polyp score, SNOT20 questionnaire, olfactometry, the total IgE concentration in peripheral blood as well as the eosinophil cell count in peripheral blood were recorded. The change of parameters was evaluated over one year and the correlation between clinical effectiveness and nasal differential cytology was analyzed.

Results

In both MGG (p<0.0001) and ICC analysis (p<0.001) a significant decrease of eosinophils was seen under Dupilumab treatment. When patients were divided into a Eo-low- (<21%) and Eo-high- (≥21%) group according to the percentage eosinophils in nasal swab catology in the first study visit, the Eo-high-group showed a greater change of eosinophils over time (Δ17.82) compared to the Eo-low-group (Δ10.67) but, however, no better response to therapy. The polyp score, SNOT20 questionnaire, and total IgE concentration in peripheral blood showed a significant decrease during the observation period (p<0.0001).

Discussion

Nasal swab cytology as an easy-to-apply diagnostic method allows detection and quantification of the different cell populations within the nasal mucosa at a given time. The nasal differential cytology showed a significant decrease of eosinophils during Dupilumab therapy and can therefore be used as non-invasvive method for monitoring therapy success of this cost intensive therapy and potentially can allow an optimized individual therapy planning and management for CRSwNP patients. Since the validity of initial nasal swab eosinophil cell count as a predictive biomarker for therapy response was limited in our study, additional studies including larger number of participants will be necessary to further evaluate the potential benefits for clinical practice of this new diagnostic method.

Personalized Management of Patients with Chronic Rhinosinusitis with Nasal Polyps in Clinical Practice: A Multidisciplinary Consensus Statement

Chronic rhinosinusitis (CRS) is a sino-nasal chronic inflammatory disease, occurring in 5–15% of the general population. CRS with nasal polyps (CRSwNP) is present in up to 30% of the CRS population. One-third of CRSwNP patients suffer from disease that is uncontrolled by current standards of care. Biologics are an emerging treatment option for patients with severe uncontrolled CRSwNP, but their positioning in the treatment algorithm is under discussion. Effective endotyping of CRSwNP patients who could benefit from biologics treatment is required, as suggested by international guidelines. Other issues affecting management include comorbidities, such as allergy, non-steroidal anti-inflammatory drug–exacerbated respiratory disease, and asthma. Therefore, the choice of treatment in CRSwNP patients depends on many factors. A multidisciplinary approach may improve CRSwNP management in patients with comorbidities, but currently there is no shared management model. We summarize the outcomes of a Delphi process involving a multidisciplinary panel of otolaryngologists, pulmonologists, and allergist-immunologists involved in the management of CRSwNP, who attempted to reach consensus on key statements relating to the diagnosis, endotyping, classification and management (including the place of biologics) of CRSwNP patients.

Biologics for severe uncontrolled chronic rhinosinusitis with nasal polyps: a change management approach. Consensus of the Joint Committee of Italian Society of Otorhinolaryngology on biologics in rhinology

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous inflammatory condition of nasal mucosa and paranasal sinuses, predominantly mediated by type 2 inflammation and often associated with comorbid asthma and/or Exacerbated Respiratory Disease (N-ERD). The standard of care involves local and systemic corticosteroids and/or sinonasal surgery, although these options may be associated with recurrences and patients may require revision surgery. Difficult-to-treat patients, in fact, have a more severe disease requiring high systemic corticosteroid use and/or multiple sinonasal surgeries. Literature data suggests that biologic agents targeting specific key effectors of type 2 inflammation may offer supplemental therapy for patients with severe and uncontrolled CRSwNP, leading to significant improvement in several outcomes. For these reasons, over the years the endotyping of the disease has become increasingly important. Herein, we provide not only an update on the existing studies about the most promising biologics in CRSwNP, but also critical discussion on controversies about the use of biologics in severe uncontrolled CRSwNP. We finally provide consensus on strategic issues gathered among experts of the Joint Committee of Italian Society of Otorhinolaryngology on biologics in order to offer the best care for difficult to treat patients.