IL-4Rα signaling promotes barrier-altering oncostatin M and IL-6 production in aspirin-exacerbated respiratory disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is a severe disease involving dysregulated type 2 inflammation. However, the role other inflammatory pathways play in AERD is poorly understood.

OBJECTIVE

We sought to broadly define the inflammatory milieu of the upper respiratory tract in AERD and to determine the effects of IL-4Rα inhibition on mediators of nasal inflammation.

METHODS

Twenty-two AERD patients treated with dupilumab for 3 months were followed over 3 visits and compared to 10 healthy controls. Nasal fluid was assessed for 45 cytokines and chemokines using Olink Target 48. Blood neutrophils and cultured human mast cells, monocytes/macrophages, and nasal fibroblasts were assessed for response to IL-4/13 stimulation in vitro.

RESULTS

Of the nasal fluid cytokines measured, nearly one-third were higher in AERD patients compared to healthy controls, including IL-6 and the IL-6 family-related cytokine oncostatin M (OSM), both of which correlated with nasal albumin levels, a marker of epithelial barrier dysregulation. Dupilumab significantly decreased many nasal mediators, including OSM and IL-6. IL-4 stimulation induced OSM production from mast cells and macrophages, but not from neutrophils, and OSM and IL-13 stimulation induced IL-6 production from nasal fibroblasts.

CONCLUSION

In addition to type 2 inflammation, innate and IL-6-related cytokines are also elevated in the respiratory tract in AERD. Both OSM and IL-6 are locally produced in nasal polyps and likely promote pathology by negatively affecting epithelial barrier function. IL-4Rα blockade, though seemingly directed at type 2 inflammation, also decreases mediators of innate inflammation and epithelial dysregulation, which may contribute to dupilumab's therapeutic efficacy in AERD.

TCF1-LEF1 co-expression identifies a multipotent progenitor cell (TH2-MPP) across human allergic diseases

Repetitive exposure to antigen in chronic infection and cancer drives T cell exhaustion, limiting adaptive immunity. In contrast, aberrant, sustained T cell responses can persist over decades in human allergic disease. To understand these divergent outcomes, we employed bioinformatic, immunophenotyping and functional approaches with human diseased tissues, identifying an abundant population of type 2 helper T (TH2) cells with co-expression of TCF7 and LEF1, and features of chronic activation. These cells, which we termed TH2-multipotent progenitors (TH2-MPP) could self-renew and differentiate into cytokine-producing effector cells, regulatory T (Treg) cells and follicular helper T (TFH) cells. Single-cell T-cell-receptor lineage tracing confirmed lineage relationships between TH2-MPP, TH2 effectors, Treg cells and TFH cells. TH2-MPP persisted despite in vivo IL-4 receptor blockade, while thymic stromal lymphopoietin (TSLP) drove selective expansion of progenitor cells and rendered them insensitive to glucocorticoid-induced apoptosis in vitro. Together, our data identify TH2-MPP as an aberrant T cell population with the potential to sustain type 2 inflammation and support the paradigm that chronic T cell responses can be coordinated over time by progenitor cells.

Optimizing cryopreservation of nasal polyp tissue for cellular functional studies and single-cell RNA sequencing

KEY POINTS

Mast cell numbers were reduced in samples cryopreserved as whole tissue chunks. Thawed epithelial cells had reduced proliferation rates when preserved as dissociated cell suspensions. The right cryopreservation method to choose may depend on the goals and cell-type focus of the project.

A nasal cell atlas reveals heterogeneity of tuft cells and their role in directing olfactory stem cell proliferation

The olfactory neuroepithelium serves as a sensory organ for odors and forms part of the nasal mucosal barrier. Olfactory sensory neurons are surrounded and supported by epithelial cells. Among them, microvillous cells (MVCs) are strategically positioned at the apical surface, but their specific functions are enigmatic, and their relationship to the other specialized epithelial cells is unclear. Here, we establish that the family of MVCs comprises tuft cells and ionocytes in both mice and humans. Integrating analysis of the respiratory and olfactory epithelia, we define the distinct receptor expression of TRPM5+ tuft-MVCs compared with Gɑ-gustducinhigh respiratory tuft cells and characterize a previously undescribed population of glandular DCLK1+ tuft cells. To establish how allergen sensing by tuft-MVCs might direct olfactory mucosal responses, we used an integrated single-cell transcriptional and protein analysis. Inhalation of Alternaria induced mucosal epithelial effector molecules including Chil4 and a distinct pathway leading to proliferation of the quiescent olfactory horizontal basal stem cell (HBC) pool, both triggered in the absence of olfactory apoptosis. Alternaria- and ATP-elicited HBC proliferation was dependent on TRPM5+ tuft-MVCs, identifying these specialized epithelial cells as regulators of olfactory stem cell responses. Together, our data provide high-resolution characterization of nasal tuft cell heterogeneity and identify a function of TRPM5+ tuft-MVCs in directing the olfactory mucosal response to allergens.

Nasal polyp antibody-secreting cells display proliferation signature in aspirin-exacerbated respiratory disease

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) causes nasal obstruction and olfactory dysfunction. Aspirin-exacerbated respiratory disease (AERD) is the triad of CRSwNP, asthma, and respiratory reactions to COX-1 inhibitors. Patients with AERD have elevated nasal IL-5 levels and high numbers of antibody-secreting cells (ASCs), including plasma cells and plasmablasts, in their polyp tissue; in addition, their nasal polyp (NP) IgE levels are correlated with disease severity and recurrence of nasal polyposis.

OBJECTIVE

We sought to explore differences in the transcriptomic profile, activation markers, and IL-5Rα expression and function of NP ASCs from patients with AERD and CRSwNP.

METHODS

NP tissue was collected from patients with AERD and CRSwNP and digested into single-cell suspensions. NP cells were analyzed for protein expression by mass cytometry. For IL-5Rα functional studies, plasma cells were purified and cultured in vitro with or without IL-5 and analyzed by bulk RNA sequencing.

RESULTS

Compared with polyp tissue from patients with CRSwNP, polyp tissue from patients with AERD contained significantly more ASCs and had increased ASC expression of IL-5Rα. ASCs from patients with AERD expressed higher protein levels of B-cell activation and regulatory markers (CD40, CD19, CD32, and CD38) and the proliferation marker Ki-67. ASCs from patients with AERD also expressed more IL5RA, IGHE, and cell cycle- and proliferation-related transcripts (CCND2, MKI67, CDC25A, and CDC25B) than did ASCs from patients with CRSwNP. Stimulation of plasma cells from patients with AERD with IL-5 induced key cell cycle genes (CCND2 and PTP4A3), whereas IL-5 stimulation of ASCs from patients with CRSwNP induced few transcriptomic changes.

CONCLUSION

NP tissue ASCs from patients with AERD express higher levels of functional IL-5Rα and markers associated with cell cycling and proliferation than do ASCs from patients with aspirin-tolerant CRSwNP.

Not just snot: Local inflammatory profiles in patients with aspirin-exacerbated respiratory disease differ from patients with aspirin-tolerant chronic rhinosinusitis

KEY POINTS

IL-5, CCL2, and CXCL8 in sinus mucous are higher in patients with AERD relative to aspirin-tolerant patients with CRS These mediators are pleiotropic, leading to widescale inflammatory processes contributing to AERD AERD is not only a T2 disease but heterogeneous: this may explain the refractory nature of AERD.

Local cytokine levels associate with SNOT-22 and UPSIT scores in chronic rhinosinusitis

KEY POINTS

Elevated IL-5, IL-13, IL-33, and CCL2 correlate with lower UPSIT scores in CRS and AERD patients. Elevated IL-5, IL-13, TNF-α, CCL2, and CXCL-8 correlate with higher SNOT-22 scores in CRS and AERD patients.

Validation of a questionnaire assessing smell loss in an international aspirin-exacerbated respiratory disease population

Background: Olfactory dysfunction (OD) and smell loss affects aspects of patients' everyday life and lowers their quality of life. OD questionnaires are considered one of the core-outcome measures in chronic rhinosinusitis, but many existing smell loss questionnaires contained pandemic-prohibitive questions on social gatherings or restaurant visits, were too culture specific or gender specific, or were overly long and cumbersome. Objective: We aimed to develop a new brief questionnaire to assess the impact and consequences of smell loss and its burden on daily life. This study validates this new, short, multicultural, dichotomized questionnaire in an international population that has aspirin-exacerbated disease (AERD). Methods: The Consequences of Smell Loss (COSL) questionnaire was developed and content validity was assessed by experts and patients at Brigham and Women's Hospital. The questionnaire, along with other validated quality-of-life surveys, was answered by 853 patients with AERD. We evaluated the factor structure, reliability, validity, and discriminative ability of the COSL questionnaire. Results: The final version of the COSL questionnaire consisted of 13 items divided into three subdomains (emotional distress, food and safety, and physical health) through factor analysis. The Cronbach α for internal consistency was 0.82. Convergent and discriminant validity with the 22-item Sinonasal Outcome Test (SNOT-22), Healthy Days Core Module-4, Patient Health Questionnaire-4, and a specific question on taste and smell were high (p < 0.0001 for all). The COSL questionnaire score was associated with SNOT-22 categories (p < 0.001) and was categorized as follows: normal, 0-1 points; very few consequences, 2-3 points; few, 4 points; moderate, 5-6 points; and severe, 7-13 points. Conclusion: The COSL questionnaire is a new, brief, valid, reliable tool that can effectively screen for a high burden of OD in patients with AERD and has the potential to be used in other patient populations with OD as well.

Progestogen Hypersensitivity

Progestogen hypersensitivity (PH) is a heterogeneous disease characterized by diverse cutaneous manifestations, bronchospasm, and/or anaphylaxis. Possible triggers include ovarian progesterone and exogenous progestogens. The timing of symptoms is critical to diagnose PH: during the luteal phase of the menstrual cycle for the endogenous form and after exposure to progestins for exogenous PH. Diagnostic modalities such as progesterone skin testing have low sensitivity and specificity for PH. When exogenous PH is suspected, the allergist should consider a progestogen challenge. Treatment strategies should be tailored for each patient, including symptom-directed therapies, ovulation suppression, and progesterone desensitization. Future studies should explore the mechanisms of PH, validation of diagnostic criteria, and standardization of treatment strategies.

Increased epithelial mTORC1 activity in chronic rhinosinusitis with nasal polyps

Background

The airway epithelium plays a central role in the pathogenesis of chronic respiratory diseases such as asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), but the mechanisms by which airway epithelial cells (EpCs) maintain inflammation are poorly understood.

Objective

We hypothesized that transcriptomic assessment of sorted airway EpCs across the spectrum of differentiation would allow us to define mechanisms by which EpCs perpetuate airway inflammation.

Methods

Ethmoid sinus EpCs from adult patients with CRS were sorted into 3 subsets, bulk RNA sequenced, and analyzed for differentially expressed genes and pathways. Single cell RNA-seq (scRNA-seq) datasets from eosinophilic and non-eosinophilic CRSwNP and bulk RNA-seq of EpCs from mild/moderate and severe asthma were assessed. Immunofluorescent staining and ex vivo functional analysis of sinus EpCs were used to validate our findings.

Results

Analysis within and across purified EpC subsets revealed an enrichment in glycolytic programming in CRSwNP vs CRSsNP. Correlation analysis identified mammalian target of rapamycin complex 1 (mTORC1) as a potential regulator of the glycolytic program and identified EpC expression of cytokines and wound healing genes as potential sequelae. mTORC1 activity was upregulated in CRSwNP, and ex vivo inhibition demonstrated that mTOR is critical for EpC generation of CXCL8, IL-33, and CXCL2. Across patient samples, the degree of glycolytic activity was associated with T2 inflammation in CRSwNP, and with both T2 and non-T2 inflammation in severe asthma.

Conclusions

Together, these findings highlight a metabolic axis required to support epithelial generation of cytokines critical to both chronic T2 and non-T2 inflammation in CRSwNP and asthma.

Eosinophils and tissue remodeling: Relevance to airway disease

The ability of human tissue to reorganize and restore its existing structure underlies tissue homeostasis in the healthy airways, but in disease can persist without normal resolution, leading to an altered airway structure. Eosinophils play a cardinal role in airway remodeling both in health and disease, driving epithelial homeostasis and extracellular matrix turnover. Physiological consequences associated with eosinophil-driven remodeling include impaired lung function and reduced bronchodilator reversibility in asthma, and obstructed airflow in chronic rhinosinusitis with nasal polyps. Given the contribution of airway remodeling to the development and persistence of symptoms in airways disease, targeting remodeling is an important therapeutic consideration. Indeed, there is early evidence that eosinophil attenuation may reduce remodeling and disease progression in asthma. This review provides an overview of tissue remodeling in both health and airway disease with a particular focus on eosinophilic asthma and chronic rhinosinusitis with nasal polyps, as well as the role of eosinophils in these processes and the implications for therapeutic interventions. Areas for future research are also noted, to help improve our understanding of the homeostatic and pathological roles of eosinophils in tissue remodeling, which should aid the development of targeted and effective treatments for eosinophilic diseases of the airways.

Aspirin-exacerbated respiratory disease: Updates in the era of biologics

OBJECTIVE

Aspirin-exacerbated respiratory disease (AERD) is a chronic respiratory condition characterized by severe chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic asthma, and respiratory reactions to cyclooxygenase inhibitors. The management of AERD has evolved recently with the availability of respiratory biologics for treatment of severe asthma and CRSwNP. The objective of this review is to provide an update on the management of AERD in the era of respiratory biologic therapy.

DATA SOURCES

A literature review of pathogenesis and treatment of AERD, with a specific focus on biologic therapies in AERD, was performed through publications gathered from PubMed.

STUDY SELECTIONS

Original research, randomized controlled trials, retrospective studies, meta-analyses, and case series of high relevance are selected and reviewed.

RESULTS

Aspirin therapy after desensitization (ATAD) and respiratory biologic therapies targeting interleukin (IL)-4Rα, IL-5, IL-5Rα, and immunoglobulin E, all have some efficacy in the treatment of CRSwNP and asthma in patients with AERD. There are currently no head-to-head studies comparing ATAD vs respiratory biologic therapy, or specific respiratory biologics, for asthma and CRSwNP in patients with AERD.

CONCLUSION

Advances in our understanding of the fundamental drivers of the chronic respiratory inflammation in asthma and CRSwNP have led to the identification of several potential therapeutic targets for these diseases that can be used in patients with AERD. Further study of the use of ATAD and biologic therapy, independently and together, will help to inform future treatment algorithms for patients with AERD.

Trial of thromboxane receptor inhibition with ifetroban: TP receptors regulate eicosanoid homeostasis in aspirin-exacerbated respiratory disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is the triad of asthma, nasal polyposis, and respiratory reactions to COX-1 inhibitors. Overproduction of cysteinyl leukotrienes and underproduction of prostaglandin E2 (PGE2) are hallmarks of AERD. A mouse model predicted a key role for the thromboxane-prostanoid (TP) receptor in AERD.

OBJECTIVE

Our aim was to determine whether ifetroban, a TP receptor antagonist, attenuates aspirin-induced respiratory symptoms in patients with AERD.

METHODS

A total of 35 patients with AERD completed a 4-week double-blinded, placebo-controlled trial of ifetroban and underwent an oral aspirin challenge. The primary outcome was change in the provocative dose of aspirin that caused a 2-point increase in Total Nasal Symptom Score. Changes in lung function, eicosanoid levels, and platelet and mast cell activation were assessed. Cultured human nasal fibroblasts were stimulated with or without the TP agonist U46619 and assayed for prostanoid production.

RESULTS

Ifetroban was well tolerated in AERD and did not change the mean 2-point increase in Total Nasal Symptom Score (P = .763). Participants taking ifetroban had greater aspirin-induced nasal symptoms and a greater decline in FEV1 value than did participants receiving placebo (-18.8% ± 3.6% with ifetroban vs -8.4% ± 2.1% with placebo [P = .017]). Four weeks of ifetroban significantly increased urinary leukotriene E4 levels and decreased nasal PGE2 levels compared with placebo. Peak aspirin-induced urinary thromboxane levels correlated with peak urinary leukotriene E4 and prostaglandin D2 metabolite levels in participants taking ifetroban. U46119 significantly potentiated the production of PGE2 by cultured nasal fibroblasts from subjects with AERD but not by cultured nasal fibroblasts from controls without polypoid sinusitis.

CONCLUSION

Contrary to our hypothesis, TP receptor blockade worsened aspirin-induced reactions in AERD, possibly by exacerbating dysregulation of the eicosanoid system. TP signaling on stromal cells may be critical to maintaining PGE2 production when COX-2 function is low.

Type 2 inflammation drives an airway basal stem cell program through insulin receptor substrate signaling

BACKGROUND

Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a type 2 (T2) inflammatory disease associated with an increased number of airway basal cells (BCs). Recent studies have identified transcriptionally distinct BCs, but the molecular pathways that support or inhibit human BC proliferation and differentiation are largely unknown.

OBJECTIVE

We sought to determine the role of T2 cytokines in regulating airway BCs.

METHODS

Single-cell and bulk RNA sequencing of sinus and lung airway epithelial cells was analyzed. Human sinus BCs were stimulated with IL-4 and IL-13 in the presence and absence of inhibitors of IL-4R signaling. Confocal analysis of human sinus tissue and murine airway was performed. Murine BC subsets were sorted for RNA sequencing and functional assays. Fate labeling was performed in a murine model of tracheal injury and regeneration.

RESULTS

Two subsets of BCs were found in human and murine respiratory mucosa distinguished by the expression of basal cell adhesion molecule (BCAM). BCAM expression identifies airway stem cells among P63+KRT5+NGFR+ BCs. In the sinonasal mucosa, BCAMhi BCs expressing TSLP, IL33, CCL26, and the canonical BC transcription factor TP63 are increased in patients with CRSwNP. In cultured BCs, IL-4/IL-13 increases the expression of BCAM and TP63 through an insulin receptor substrate-dependent signaling pathway that is increased in CRSwNP.

CONCLUSIONS

These findings establish BCAM as a marker of airway stem cells among the BC pool and demonstrate that airway epithelial remodeling in T2 inflammation extends beyond goblet cell metaplasia to the support of a BC stem state poised to perpetuate inflammation.

Endotyping Chronic Rhinosinusitis with Nasal Polyps: Understanding Inflammation Beyond Phenotypes

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogenous group of inflammatory conditions impacting the nose and paranasal sinuses. Our understanding of the underlying pathobiology of CRSwNP has substantially improved due to ongoing translational research efforts. Advances in treatment options, including targeted respiratory biologic therapy for CRSwNP, allow for more personalized approaches for CRSwNP patient care. Patients with CRSwNP are typically classified to one or more endotype based on the presence of type 1, type 2, and type 3 inflammation. This review will discuss recent advances in our understanding of CRSwNP and how this may impact current and future treatment approaches for patients with CRSwNP.

Loss of smell in patients with aspirin-exacerbated respiratory disease impacts mental health and quality of life

BACKGROUND

The impact of anosmia on quality-of-life (QoL) for patients with aspirin-exacerbated respiratory disease (AERD) is poorly understood. We aimed to investigate how the severity of smell loss and olfactory dysfunction (OD) in patients with AERD affects their QoL, mental health and physical well-being.

METHODS

Five validated QoL questionnaires (Sinonasal Outcome Test-22, Asthma Control Test, Healthy Days Core Module-4, Short Form-36 and Patient Health Questionnaire-4) and two newly developed questionnaires assessing severity and consequences of OD were electronically sent to all 2913 patients in the Brigham and Women's Hospital AERD registry. Responses were received from 853 participants for analysis.

RESULTS

Overall, 85% of participants reported a present diminished sense of smell and/or taste, and 30% categorized their OD severity was, "as bad as it can be." There were significant relationships between the severity of self-reported OD and both psychological distress and general health scores, even after adjusting for asthma control. Additionally, incidence rates for physically and mentally unhealthy days in the prior month were higher for patients with moderate or severe OD than for normosmic patients. Patients with diminished smell responded that they could not identify spoiled food (86%), did not enjoy food (71%), felt unsafe (63%) and had encountered dangerous situations (51%) as consequences of their OD.

CONCLUSIONS

Anosmia and hyposmia severely impact the physical, emotional and mental health of AERD patients, and lead to safety concerns in their daily lives. The importance of olfaction and the relevance of OD to patients' QoL should be acknowledged and evaluated by clinicians caring for these patients.

Rapid and sustained effect of dupilumab on clinical and mechanistic outcomes in aspirin-exacerbated respiratory disease

BACKGROUND

Dupilumab, a mAb targeting IL-4Rα, improves upper and lower airway symptoms in patients with aspirin-exacerbated respiratory disease (AERD), but the mechanisms leading to clinical improvement are not fully elucidated.

OBJECTIVE

Our aim was to identify the mechanistic basis of clinical improvement in patients with AERD treated with dupilumab.

METHODS

A total of 22 patients with AERD were treated with dupilumab for 3 months for severe asthma and/or chronic rhinosinusitis with nasal polyps. Clinical outcomes were assessed at baseline and at 1 and 3 months after initiation of dupilumab. Nasal fluid, urine, blood, and inferior turbinate scrapings were collected at the 3 time points for determination of mediator levels, cellular assays, and RNA sequencing.

RESULTS

Participants had rapid improvement in clinical measures, including sense of smell, sinonasal symptoms, and lung function after 1 month of treatment with dupilumab; the improvements were sustained after 3 months of dupilumab. Baseline severity of smell loss was correlated with lower nasal prostaglandin E₂ levels. Dupilumab increased nasal prostaglandin E₂ level and decreased levels of nasal albumin, nasal and urinary leukotriene E₄, and serum and nasal IgE. Transcripts related to epithelial dysfunction and leukocyte activation and migration were downregulated in inferior turbinate tissue after treatment with dupilumab. There were no dupilumab-induced changes in nasal eosinophilia.

CONCLUSION

Inhibition of IL-4Rα in AERD led to rapid improvement in respiratory symptoms and smell, with a concomitant improvement in epithelial barrier function, a decrease in inflammatory eicosanoid levels, and an increase in the anti-inflammatory eicosanoid prostaglandin E₂ level. The therapeutic effects of dupilumab are likely due to decreased IL-4Rα signaling on respiratory tissue granulocytes, epithelial cells, and B cells.

Improvement in Health-Related Quality of Life with Dupilumab in Patients with Moderate-to-Severe Asthma with Comorbid Chronic Rhinosinusitis with/without Nasal Polyps: An Analysis of the QUEST Study

Patients with asthma frequently have comorbid chronic rhinosinusitis (CRS) with or without nasal polyps, increasing disease burden and complicating treatment. These post hoc analyses investigated disease-specific health-related quality of life (HRQoL) and general health status in the randomized, placebo-controlled QUEST study (NCT02414854) in patients treated with dupilumab for moderate-to-severe asthma with comorbid CRS. Patients received 300 mg of dupilumab or placebo every 2 weeks for 52 weeks. CRS HRQoL was assessed by the 22-item Sino-Nasal Outcome Test (SNOT-22; items scored 0–5). The 22 items are categorized into 5 domains (nasal, ear/facial, sleep, function, and emotion), and patients report the top 5 most important items affecting their health. General health status was assessed by Euro-QoL visual analog scale (EQ-VAS). Of 1902 patients, 382 (20.1%) self-reported comorbid CRS; 193 patients receiving dupilumab 300 mg q2w or matched placebo were included in this analysis. At baseline, the most impacted SNOT-22 domain was nasal, and general health status was below population norms. Patients rated “decreased sense of taste/smell,” “nasal blockage,” “cough,” “reduced productivity,” and “wake up tired” as the 5 most important SNOT-22 items affecting their health. Percentage change from baseline in SNOT-22 total score was significantly greater for dupilumab vs placebo at Weeks 24, 36, and 52 (all p < 0.05). Improvements from baseline were significantly greater for dupilumab vs placebo at Week 52 for all SNOT-22 domains (p < 0.05), except emotion. At Week 52, significant changes from baseline with dupilumab vs placebo were observed for all 5 most important SNOT-22 items affecting their health (all p < 0.05). EQ-VAS was significantly improved with dupilumab vs placebo by Week 12, with improvements sustained to Week 52 (all p < 0.01). In patients with moderate-to-severe asthma who self-reported comorbid CRS, dupilumab treatment vs placebo improved CRS-specific HRQoL and general health status.

Chronic Rhinosinusitis With Nasal Polyps: Quality of Life in the Biologics Era

Chronic rhinosinusitis (CRS) affects up to 12% of the general population and is traditionally divided into two main phenotypic subsets, based on the presence of nasal polyps (CRSwNP) or their absence. It is well-established that many patients with CRSwNP report poor quality of life (QoL), which is further compromised by comorbidities (eg, asthma, bronchiectasis, aspirin-exacerbated respiratory disease). Chronic rhinosinusitis CRS with nasal polyps is managed with a combination of medical therapy and surgical interventions, and biologics are emerging as a promising new treatment option for patients with inadequate response to the standard of care. A range of patient-reported outcome measures have been used to assess QoL for patients with CRSwNP in clinical trials, including disease-specific questionnaires (eg, Sino-Nasal Outcome Test-22) and generic ones (eg, Short Form-36). Significantly impaired QoL has been identified as a criterion for the indication to use biologics in patients with CRSwNP. This review summarizes clinical evidence (2010-2021) on QoL outcomes with currently available treatments for CRSwNP and assesses the improvement in QoL after biologic treatments, especially for patients with comorbidities reported in interventional studies (randomized controlled trials and real-world experience).

Aspirin desensitization and biologics in aspirin-exacerbated respiratory disease: Efficacy, tolerability, and patient experience

BACKGROUND

Patterns of medication use and efficacy in aspirin-exacerbated respiratory disease (AERD) have not been well characterized, especially since the advent of respiratory biologics. Aspirin therapy after desensitization (ATAD) is efficacious for upper and lower respiratory symptoms for patients with AERD, though aspirin-related adverse effects can limit therapy. The optimal coordination of ATAD and respiratory biologics for the treatment of AERD remains unclear.

OBJECTIVE

We aimed to characterize patterns of medication use and treatment experience with biologics and ATAD in AERD.

METHODS

We surveyed 98 patients with AERD recruited from the Brigham and Women's Hospital AERD registry. Patients completed an online questionnaire describing their medication history and treatment experience.

RESULTS

A total of 52 (53.0%) patients reported a history of use of one or more respiratory biologics (omalizumab, mepolizumab, reslizumab, benralizumab, or dupilumab), and 84 (85.7%) reported undergoing aspirin desensitization. There were 24 patients (24.4%) who reported concurrent use of a biologic and ATAD. Compared with those taking ATAD alone, patients taking a biologic and ATAD concurrently were less likely to report that aspirin was effective for their AERD symptoms (odds ratio, 0.161 [95% confidence interval, 0.03-0.76]; P =.02). Whereas patients reported varying efficacy with biologics, dupilumab had the highest odds of patients reporting it worked "very well" (odds ratio, 17.58 [95% confidence interval, 5.68-54.35]; P < .001).

CONCLUSION

Biologics are emerging as a treatment option for AERD and are generally well tolerated. Biologic efficacy in AERD is variable by agent, though most patients taking dupilumab found it to be effective. Patients on a biologic in conjunction with ATAD may represent a more severe subset of AERD for which ATAD alone is insufficient.

Mepolizumab targets multiple immune cells in aspirin-exacerbated respiratory disease

BACKGROUND

Eosinophilic asthma and nasal polyposis are hallmarks of aspirin-exacerbated respiratory disease (AERD), and IL-5 inhibition has been shown to provide therapeutic benefit. However, IL-5Rα is expressed on many cells in addition to eosinophils, and the mechanisms by which IL-5 inhibition leads to clinical benefit in eosinophilic asthma and nasal polyposis are unlikely to be due exclusively to antieosinophil effects.

OBJECTIVE

We sought to identify the mechanisms by which anti-IL-5 treatment with mepolizumab improves respiratory inflammation in AERD.

METHODS

The clinical characteristics, circulating granulocytes, nasal scraping transcripts, eosinophilic cationic protein, tryptase, and antibody levels, and urinary and nasal eicosanoid levels were measured for 18 subjects with AERD who were taking mepolizumab and compared with those of 18 matched subjects with AERD who were not taking mepolizumab.

RESULTS

Subjects taking mepolizumab had significantly fewer peripheral blood eosinophils and basophils, and those cells that remained had higher surface CRTH2 expression than did the cells from subjects not taking mepolizumab. Nasal prostaglandin F_2α, prostaglandin D₂ metabolites, leukotriene B₄, and thromboxane levels were lower in subjects taking mepolizumab, as were urinary levels of tetranor-prostaglandin D₂ and leukotriene E₄. The nasal epithelial cell transcripts that were overexpressed among subjects with AERD who were taking mepolizumab were enriched for genes involved in tight junction formation and cilium organization. Nasal and urinary prostaglandin E₂, tryptase, and antibody levels were not different between the 2 groups.

CONCLUSION

IL-5 inhibition in AERD decreases production of inflammatory eicosanoids and upregulates tight junction-associated nasal epithelial cell transcripts, likely due to decreased IL-5 signaling on tissue mast cells, eosinophils, and epithelial cells. These direct effects on multiple relevant immune cells contribute to the mechanism of benefit afforded by mepolizumab.

Human airway mast cells proliferate and acquire distinct inflammation-driven phenotypes during type 2 inflammation

Mast cells (MCs) play a pathobiologic role in type 2 (T2) allergic inflammatory diseases of the airway, including asthma and chronic rhinosinusitis with nasal polyposis (CRSwNP). Distinct MC subsets infiltrate the airway mucosa in T2 disease, including subepithelial MCs expressing the proteases tryptase and chymase (MC_TC) and epithelial MCs expressing tryptase without chymase (MC_T). However, mechanisms underlying MC expansion and the transcriptional programs underlying their heterogeneity are poorly understood. Here, we use flow cytometry and single-cell RNA-sequencing (scRNA-seq) to conduct a comprehensive analysis of human MC hyperplasia in CRSwNP, a T2 cytokine-mediated inflammatory disease. We link discrete cell surface phenotypes to the distinct transcriptomes of CRSwNP MC_T and MC_TC, which represent polarized ends of a transcriptional gradient of nasal polyp MCs. We find a subepithelial population of CD38^highCD117^high MCs that is markedly expanded during T2 inflammation. These CD38^highCD117^high MCs exhibit an intermediate phenotype relative to the expanded MC_T and MC_TC subsets. CD38^highCD117^high MCs are distinct from circulating MC progenitors and are enriched for proliferation, which is markedly increased in CRSwNP patients with aspirin-exacerbated respiratory disease, a severe disease subset characterized by increased MC burden and elevated MC activation. We observe that MCs expressing a polyp MC_T-like effector program are also found within the lung during fibrotic diseases and asthma, and further identify marked differences between MC_TC in nasal polyps and skin. These results indicate that MCs display distinct inflammation-associated effector programs and suggest that in situ MC proliferation is a major component of MC hyperplasia in human T2 inflammation.

The role of aspirin desensitization followed by oral aspirin therapy in managing patients with aspirin-exacerbated respiratory disease: A Work Group Report from the Rhinitis, Rhinosinusitis and Ocular Allergy Committee of the American Academy of Allergy, Asthma & Immunology

Aspirin-exacerbated respiratory disease (AERD) is characterized by the clinical triad of chronic rhinosinusitis with nasal polyps, asthma, and an intolerance to medications that inhibit the cycloxgenase-1 enzyme. Patients with AERD on average have more severe respiratory disease compared with patients with chronic rhinosinusitis with nasal polyps and/or asthma alone. Although patients with AERD traditionally develop significant upper and lower respiratory tract symptoms on ingestion of cycloxgenase-1 inhibitors, most of these same patients report clinical benefit when desensitized to aspirin and maintained on daily aspirin therapy. This Work Group Report provides a comprehensive review of aspirin challenges, aspirin desensitizations, and maintenance aspirin therapy in patients with AERD. Identification of appropriate candidates, indications and contraindications, medical and surgical optimization strategies, protocols, medical management during the desensitization, and recommendations for maintenance aspirin therapy following desensitization are reviewed. Also included is a summary of studies evaluating the clinical efficacy of aspirin therapy after desensitization as well as a discussion on the possible cellular and molecular mechanisms explaining how this therapy provides unique benefit to patients with AERD.

Aspirin-Exacerbated Respiratory Disease: Association Between Patient-Reported Sinus and Asthma Morbidity

BACKGROUND

The association between sinonasal and pulmonary symptoms in aspirin-exacerbated respiratory disease is not fully established.

OBJECTIVE

To characterize sinonasal and asthma symptomatology, and to determine whether reported sinonasal symptoms predict asthma severity.

METHODS

Prospectively collected data from an aspirin-exacerbated respiratory disease registry cohort were included from 2013 to 2018. Sinonasal symptomatology measured by Sino-Nasal Outcomes Test (SNOT) 22-item total scores was used as the predictor variable, with Asthma Control Test (ACT) scores and percent predicted FEV₁ (FEV₁% predicted) as primary outcomes. All instances of paired data on the same date were used. ACT score was also evaluated with FEV₁% predicted as the outcome. Mixed effects regression was completed.

RESULTS

From 1065 aspirin-exacerbated respiratory disease registry subjects (mean age, 48.1 ± 12.8 years; 68.0% females, 29.8% males), mean SNOT-22 score was 42.3 ± 24.12 (n = 1307 observations from 869 subjects), mean ACT score was 19.4 ± 5.2 (n = 1511 observations from 931 subjects), and mean FEV₁% predicted was 82.8 ± 19.6 (n = 777 observations from 307 subjects). SNOT-22 score significantly predicted ACT scores (P < .0001, 1185 paired observations from 845 subjects) and FEV₁% predicted (P = .018, 485 observations from 246 subjects). Any 10-point increase in SNOT-22 score was associated with a 0.87-point decrease in ACT score and a 0.75% decrease in FEV₁% predicted. Any 1-point increase in ACT score was associated with a 1.0% increase in FEV₁% predicted (P < .0001, 616 observations from 269 subjects). The most severe SNOT-22 symptoms were sense of smell/taste and blockage/congestion of nose.

CONCLUSIONS

SNOT-22 scores significantly predict ACT scores and FEV₁% predicted, and ACT scores significantly predict FEV₁% predicted. This study demonstrates an association between patient-reported rhinosinusitis and asthma symptom severity and subjective and objective measures of asthma severity.

SARS-CoV-2 Receptor ACE2 Is an Interferon-Stimulated Gene in Human Airway Epithelial Cells and Is Detected in Specific Cell Subsets across Tissues

There is pressing urgency to understand the pathogenesis of the severe acute respiratory syndrome coronavirus clade 2 (SARS-CoV-2), which causes the disease COVID-19. SARS-CoV-2 spike (S) protein binds angiotensin-converting enzyme 2 (ACE2), and in concert with host proteases, principally transmembrane serine protease 2 (TMPRSS2), promotes cellular entry. The cell subsets targeted by SARS-CoV-2 in host tissues and the factors that regulate ACE2 expression remain unknown. Here, we leverage human, non-human primate, and mouse single-cell RNA-sequencing (scRNA-seq) datasets across health and disease to uncover putative targets of SARS-CoV-2 among tissue-resident cell subsets. We identify ACE2 and TMPRSS2 co-expressing cells within lung type II pneumocytes, ileal absorptive enterocytes, and nasal goblet secretory cells. Strikingly, we discovered that ACE2 is a human interferon-stimulated gene (ISG) in vitro using airway epithelial cells and extend our findings to in vivo viral infections. Our data suggest that SARS-CoV-2 could exploit species-specific interferon-driven upregulation of ACE2, a tissue-protective mediator during lung injury, to enhance infection.

Biologics in chronic rhinosinusitis with nasal polyposis

OBJECTIVE

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common and heterogeneous inflammatory condition, for which the drivers of the underlying inflammation are not yet fully understood. The use of biologic therapies to target specifically relevant effector cells or cytokines in CRSwNP is a growing field of interest. The objectives of this review are to provide an update on the existing studies of biologics in CRSwNP and to identify potential future areas for further research.

DATA SOURCES

An initial literature review of biologic therapies in CRS was performed through publications gathered from a PubMed search for title/abstract containing "biologic" and "chronic rhinosinusitis." Further manuscripts describing scientific premise for each biologic were then reviewed.

STUDY SELECTIONS

A detailed review of all studies describing biologic therapies targeting inflammation in CRSwNP was performed.

RESULTS

Biologic therapies targeting interleukin (IL)-4Rα, IL-5, IL-5Rα, IL-33, immunoglobulin (Ig)E, and thymic stromal lymphopoietin (TSLP) have all been developed and have been investigated for treatment in CRSwNP, or current research suggests that they may have utility in this area. Only dupilumab, which inhibits IL-4Rα, has gained Food and Drug Administration approval for the treatment of adults with inadequately controlled CRSwNP.

CONCLUSION

Recent advances in our understanding of the fundamental drivers of the chronic respiratory inflammation in CRSwNP has led to the identification of several potential therapeutic targets for this disease. Future clinical success will rely on the availability of biomarker-based endotyping and responder analyses so that clinicians can precisely match each patient to the appropriate biologic, thereby optimizing the proper treatment strategy.

IL-5Rα marks nasal polyp IgG4- and IgE-expressing cells in aspirin-exacerbated respiratory disease

BACKGROUND

The cause of severe nasal polyposis in aspirin-exacerbated respiratory disease (AERD) is unknown. Elevated antibody levels have been associated with disease severity in nasal polyps, but upstream drivers of local antibody production in nasal polyps are undetermined.

OBJECTIVE

We sought to identify upstream drivers and phenotypic properties of local antibody-expressing cells in nasal polyps from subjects with AERD.

METHODS

Sinus tissue was obtained from subjects with AERD, chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP), CRS without nasal polyps, and controls without CRS. Tissue antibody levels were quantified via ELISA and immunohistochemistry and were correlated with disease severity. Antibody-expressing cells were profiled with single-cell RNA sequencing, flow cytometry, and immunofluorescence, with IL-5Rα function determined through IL-5 stimulation and subsequent RNA sequencing and quantitative PCR.

RESULTS

Tissue IgE and IgG4 levels were elevated in AERD compared with in controls (P < .01 for IgE and P < .001 for IgG4 vs CRSwNP). Subjects with AERD whose nasal polyps recurred rapidly had higher IgE levels than did subjects with AERD, with slower regrowth (P = .005). Single-cell RNA sequencing revealed increased IL5RA, IGHG4, and IGHE in antibody-expressing cells from patients with AERD compared with antibody-expressing cells from patients with CRSwNP. There were more IL-5Rα⁺ plasma cells in the polyp tissue from those with AERD than in polyp tissue from those with CRSwNP (P = .026). IL-5 stimulation of plasma cells in vitro induced changes in a distinct set of transcripts.

CONCLUSIONS

Our study identifies an increase in antibody-expressing cells in AERD defined by transcript enrichment of IL5RA and IGHG4 or IGHE, with confirmed surface expression of IL-5Rα and functional IL-5 signaling. Tissue IgE and IgG4 levels are elevated in AERD, and higher IgE levels are associated with faster nasal polyp regrowth. Our findings suggest a role for IL-5Rα⁺ antibody-expressing cells in facilitating local antibody production and severe nasal polyps in AERD.

Presentation and natural history of progestogen hypersensitivity

OBJECTIVE

To review the published medical literature on the clinical presentation, risk factors, and natural history of hypersensitivity reactions to progestogens.

DATA SOURCES

Through the use of PubMed, we conducted a review of allergy, dermatology, and obstetric literature for cases and case series of patients with hypersensitivity reactions to exogenous or endogenous progestogens. There are no longitudinal, prospective studies related to progestogen hypersensitivity.

STUDY SELECTIONS

Publications were selected that described cases that were clinically consistent with progesterone hypersensitivity and positive test results or clear symptoms with exposure to progestogens to confirm the diagnosis.

RESULTS

Progestogen hypersensitivity symptoms can be triggered by endogenous progesterone or exogenous progestins used for contraception or fertility treatments. Symptoms are varied and include dermatitis, urticaria, asthma, and anaphylaxis.

CONCLUSION

Although the medical literature on progestogen hypersensitivity is limited to case reports and small case series, significant heterogeneity exists in clinical presentation among patients.

COX-1 mediates IL-33-induced extracellular signal-regulated kinase activation in mast cells: Implications for aspirin sensitivity

BACKGROUND

Classical FcεRI-induced mast cell (MC) activation causes synthesis of arachidonic acid (AA)-derived eicosanoids (leukotriene [LT] C₄, prostaglandin [PG] D₂, and thromboxane A₂), which mediate vascular leak, bronchoconstriction, and effector cell chemotaxis. Little is known about the significance and regulation of eicosanoid generation in response to nonclassical MC activation mechanisms.

OBJECTIVES

We sought to determine the regulation and significance of MC-derived eicosanoids synthesized in response to IL-33, a cytokine critical to innate type 2 immunity.

METHODS

We used an ex vivo model of mouse bone marrow-derived mast cells and an IL-33-dependent in vivo model of aspirin-exacerbated respiratory disease (AERD).

RESULTS

IL-33 potently liberates AA and elicits LTC₄, PGD₂, and thromboxane A₂ production by bone marrow-derived mast cells. Unexpectedly, the constitutive function of COX-1 is required for IL-33 to activate group IVa cytosolic phospholipase A₂ with consequent AA release for synthesis of all eicosanoids, including CysLTs. In contrast, COX-1 was dispensable for FcεRI-driven CysLT production. Inhibition of COX-1 prevented IL-33-induced phosphorylation of extracellular signal-related kinase, an upstream effector of cytosolic phospholipase A₂, which was restored by exogenous PGH₂, implying that the effects of COX-1 required its catalytic function. Administration of a COX-1-selective antagonist to mice completely prevented the generation of both PGD₂ and LTC₄ in a model of AERD in which MC activation is IL-33 driven.

CONCLUSIONS

MC-intrinsic COX-1 amplifies IL-33-induced activation in the setting of innate type 2 immunity and might help explain the phenomenon of therapeutic desensitization to aspirin by nonselective COX inhibitors in patients with AERD.