Nasal and blood transcriptomic pathways underpinning the clinical response to grass pollen immunotherapy.

BACKGROUND: Allergen immunotherapy (AIT) is a well-established disease-modifying therapy for allergic rhinitis, yet the fundamental mechanisms underlying its clinical effect remain inadequately understood. Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy was a randomized, double-blind, placebo-controlled trial of individuals allergic to timothy grass who received 2 years of placebo (n = 30), subcutaneous immunotherapy (SCIT) (n = 27), or sublingual immunotherapy (SLIT) (n = 27) and were then followed for 1 additional year. OBJECTIVE: We used yearly biospecimens from the Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy study to identify molecular mechanisms of response. METHODS: We used longitudinal transcriptomic profiling of nasal brush and PBMC samples after allergen provocation to uncover airway and systemic expression pathways mediating responsiveness to AIT. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01335139, EudraCT Number: 2010-023536-16. RESULTS: SCIT and SLIT demonstrated similar changes in gene module expression over time. In nasal samples, alterations included downregulation of pathways of mucus hypersecretion, leukocyte migration/activation, and endoplasmic reticulum stress (log2 fold changes -0.133 to -0.640, false discovery rates [FDRs] <0.05). We observed upregulation of modules related to epithelial development, junction formation, and lipid metabolism (log2 fold changes 0.104 to 0.393, FDRs <0.05). In PBMCs, modules related to cellular stress response and type 2 cytokine signaling were reduced by immunotherapy (log2 fold changes -0.611 to -0.828, FDRs <0.05). Expression of these modules was also significantly associated with both Total Nasal Symptom Score and peak nasal inspiratory flow, indicating important links between treatment, module expression, and allergen response. CONCLUSIONS: Our results identify specific molecular responses of the nasal airway impacting barrier function, leukocyte migration activation, and mucus secretion that are affected by both SCIT and SLIT, offering potential targets to guide novel strategies for AIT.

Allergen provocation tests in respiratory research: building on 50†years of experience.

The allergen provocation test is an established model of allergic airway diseases, including asthma and allergic rhinitis, allowing the study of allergen-induced changes in respiratory physiology and inflammatory mechanisms in sensitised individuals as well as their associations. In the upper airways, allergen challenge is focused on the clinical and pathophysiological sequelae of the early allergic response, and is applied both as a diagnostic tool and in research settings. In contrast, bronchial allergen challenge has almost exclusively served as a research tool in specialised research settings with a focus on the late asthmatic response and the underlying type 2 inflammation. The allergen-induced late asthmatic response is also characterised by prolonged airway narrowing, increased nonspecific airway hyperresponsiveness and features of airway remodelling including the small airways, and hence allows the study of several key mechanisms and features of asthma. In line with these characteristics, allergen challenge has served as a valued tool to study the cross-talk of the upper and lower airways and in proof-of-mechanism studies of drug development. In recent years, several new insights into respiratory phenotypes and endotypes including the involvement of the upper and small airways, innovative biomarker sampling methods and detection techniques, refined lung function testing as well as targeted treatment options further shaped the applicability of the allergen provocation test in precision medicine. These topics, along with descriptions of subject populations and safety, in line with the updated Global Initiative for Asthma 2021 document, will be addressed in this review.

Differential induction of allergen-specific IgA responses following timothy grass subcutaneous and sublingual immunotherapy.

INTRODUCTION: There is no detailed comparison of allergen-specific immunoglobulin responses following sublingual immunotherapy (SLIT) and subcutaneous immunotherapy (SCIT). OBJECTIVE: We sought to compare nasal and systemic timothy grass pollen (TGP)-specific antibody responses during 2 years of SCIT and SLIT and 1 year after treatment discontinuation in a double-blind, double-dummy, placebo-controlled trial. METHODS: Nasal fluid and serum were obtained yearly (per-protocol population, n = 84). TGP-specific IgA1, IgA2, IgG4, IgG, and IgE were measured in nasal fluids by ELISA. TGP-specific IgA1, IgA2, and Phleum pratense (Phl p)1, 2, 4, 5b, 6, 7, 11, and 12 IgE and IgG4 were measured in sera by ELISA and ImmunoCAP, respectively. RESULTS: At years 2 and 3, TGP-IgA1/2 levels in nasal fluid were elevated in SLIT compared with SCIT (4.2- and 3.0-fold for IgA1, 2.0- and 1.8-fold for IgA2, respectively; all P < .01). TGP-IgA1 level in serum was elevated in SLIT compared with SCIT at years 1, 2, and 3 (4.6-, 5.1-, and 4.7-fold, respectively; all P < .001). Serum TGP-IgG level was higher in SCIT compared with SLIT (2.8-fold) at year 2. Serum TGP-IgG4 level was higher in SCIT compared with SLIT at years 1, 2, and 3 (10.4-, 27.4-, and 5.1-fold, respectively; all P < .01). Serum IgG4 levels to Phl p1, 2, 5b, and 6 were increased at years 1, 2, and 3 in SCIT and SLIT compared with placebo (Phl p1: 11.8- and 3.9-fold; Phl p2: 31.6- and 4.4-fold; Phl p5b: 135.5- and 5.3-fold; Phl p6: 145.4- and 14.7-fold, respectively, all at year 2 when levels peaked; P < .05). IgE to TGP in nasal fluid increased in the SLIT group at year 2 but not at year 3 compared with SCIT (2.8-fold; P = .04) and placebo (3.1-fold; P = .02). IgA to TGP and IgE and IgG4 to TGP components stratified participants according to treatment group and clinical response. CONCLUSIONS: The observed induction of IgA1/2 in SLIT and IgG4 in SCIT suggest key differences in the mechanisms of action.

Altered chromatin landscape in circulating T follicular helper and regulatory cells following grass pollen subcutaneous and sublingual immunotherapy.

BACKGROUND: Allergen-specific immunotherapy is a disease-modifying treatment that induces long-term T-cell tolerance. OBJECTIVE: We sought to evaluate the role of circulating CXCR5+PD-1+ T follicular helper (cTFH) and T follicular regulatory (TFR) cells following grass pollen subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) and the accompanying changes in their chromatin landscape. METHODS: Phenotype and function of cTFH cells were initially evaluated in the grass pollen-allergic (GPA) group (n = 28) and nonatopic healthy controls (NAC, n = 13) by mathematical algorithms developed to manage high-dimensional data and cell culture, respectively. cTFH and TFR cells were further enumerated in NAC (n = 12), GPA (n = 14), SCIT- (n = 10), and SLIT- (n = 8) treated groups. Chromatin accessibility in cTFH and TFR cells was assessed by assay for transposase-accessible chromatin sequencing (ATAC-seq) to investigate epigenetic mechanisms underlying the differences between NAC, GPA, SCIT, and SLIT groups. RESULTS: cTFH cells were shown to be distinct from TH2- and TH2A-cell subsets, capable of secreting IL-4 and IL-21. Both cytokines synergistically promoted B-cell class switching to IgE and plasma cell differentiation. Grass pollen allergen induced cTFH-cell proliferation in the GPA group but not in the NAC group (P < .05). cTFH cells were higher in the GPA group compared with the NAC group and were lower in the SCIT and SLIT groups (P < .01). Time-dependent induction of IL-4, IL-21, and IL-6 was observed in nasal mucosa following intranasal allergen challenge in the GPA group but not in SCIT and SLIT groups. TFR and IL-10+ cTFH cells were induced in SCIT and SLIT groups (all, P < .01). ATAC-seq analyses revealed differentially accessible chromatin regions in all groups. CONCLUSIONS: For the first time, we showed dysregulation of cTFH cells in the GPA group compared to NAC, SCIT, and SLIT groups and induction of TFR and IL-10+ cTFH cells following SCIT and SLIT. Changes in the chromatin landscape were observed following allergen-specific immunotherapy in cTFH and TFR cells.

Identifying key priorities for research to protect the consumer with food hypersensitivity: A UK Food Standards Agency Priority Setting Exercise.

INTRODUCTION: Food hypersensitivity (FHS), including food allergy, coeliac disease and food intolerance, is a major public health issue. The Food Standards Agency (FSA), an independent UK Government department working to protect public health and consumers' wider interests in food, sought to identify research priorities in the area of FHS. METHODS: A priority setting exercise was undertaken, using a methodology adapted from the James Lind Alliance-the first such exercise with respect to food hypersensitivity. A UK-wide public consultation was held to identify unanswered research questions. After excluding diagnostics, desensitization treatment and other questions which were out of scope for FSA or where FSA was already commissioning research, 15 indicative questions were identified and prioritized by a range of stakeholders, representing food businesses, patient groups, health care and academia, local authorities and the FSA. RESULTS: 295 responses were received during the public consultation, which were categorized into 70 sub-questions and used to define 15 key evidence uncertainties ('indicative questions') for prioritization. Using the JLA prioritization framework, this resulted in 10 priority uncertainties in evidence, from which 16 research questions were developed. These could be summarized under the following 5 themes: communication of allergens both within the food supply chain and then to the end consumer (ensuring trust in allergen communication); the impact of socio-economic factors on consumers with FHS; drivers of severe reactions; mechanism(s) underlying loss of tolerance in FHS; and the risks posed by novel allergens/processing. DISCUSSION: In this first research prioritization exercise for food allergy and FHS, key priorities identified to protect the food-allergic public were strategies to help allergic consumers to make confident food choices, prevention of FHS and increasing understanding of socio-economic impacts. Diagnosis and treatment of FHS was not considered in this prioritization.

Nasal allergen challenge and environmental exposure chamber challenge: A randomized trial comparing clinical and biological responses to cat allergen.

BACKGROUND: The direct-instillation nasal allergen challenge (NAC) and the environmental exposure chamber (EEC) are 2 methods of conducting controlled allergen provocations. The clinical and biological comparability of these methods has not been thoroughly investigated. OBJECTIVE: We sought to compare clinical and immunologic responses to cat allergen in NAC versus EEC. METHODS: Twenty-four participants were randomized to receive either NAC followed by a 2-day challenge in an EEC or a 2-day challenge in an EEC followed by NAC. Challenges were separated by 28-day washout periods. We measured total nasal symptom scores, peak nasal inspiratory flow, nasal (0-8 hours) and serum cytokines, serum antibodies, peripheral blood antigen-specific T lymphocytes, and gene expression in nasal scrapings. The primary outcome was the total nasal symptom score area under the curve for the first 3 hours after allergen exposure in NAC or after initiation of exposure in EEC. RESULTS: Both challenges increased IL-5 and IL-13 in nasal fluids and serum and resulted in altered nasal cell expression of gene modules related to mucosal biology and transcriptional regulation. Changes in gene modules, more so than cytokine measurements, showed significant associations with total nasal symptom score and peak nasal inspiratory flow. Overall, EEC exposure generated larger responses and more early terminations compared with NAC. Although the 2 challenges did not correlate in symptom magnitude or temporality, striking correlations were observed in cytokine levels. CONCLUSIONS: Although clinical outcomes of NAC and EEC were temporally different and nonequivalent in magnitude, immunologic responses were similar. Selection of a particular allergen challenge method should depend on considerations of study objectives and cost.

Role of IL-35 in sublingual allergen immunotherapy.

BACKGROUND: Grass pollen-specific immunotherapy involves immunomodulation of allergen-specific TH2 responses and induction of IL-10+ and/or TGF-ß+CD4+CD25+ regulatory T cells (induced Treg cells). IL-35+CD4+CD25+ forkhead box protein 3-negative T (IL-35-inducible regulatory T [iTR35]) cells have been reported as a novel subset of induced Treg cells with modulatory characteristics. OBJECTIVE: We sought to investigate mechanisms underlying the induction and maintenance of immunologic tolerance induced by IL-35 and iTR35 cells. METHODS: The biological effects of IL-35 were assessed on group 2 innate lymphoid cells (ILC2s); dendritic cells primed with thymic stromal lymphopoietin, IL-25, and IL-33; and B and TH2 cells by using flow cytometry and quantitative RT-PCR. Grass pollen-driven TH2 cell proliferation and cytokine production were measured by using tritiated thymidine and Luminex MagPix, respectively. iTR35 cells were quantified in patients with grass pollen allergy (seasonal allergic rhinitis [SAR] group, n = 16), sublingual immunotherapy (SLIT)-treated patients (SLIT group, n = 16), and nonatopic control subjects (NACs; NAC group, n = 16). RESULTS: The SAR group had increased proportions of ILC2s (P = .002) and IL-5+ cells (P = .042), IL-13+ cells (P = .042), and IL-5+IL-13+ ILC2s (P = .003) compared with NACs. IL-35 inhibited IL-5 and IL-13 production by ILC2s in the presence of IL-25 or IL-33 (P = .031) and allergen-driven TH2 cytokines by effector T cells. IL-35 inhibited CD40 ligand-, IL-4-, and IL-21-mediated IgE production by B cells (P = .015), allergen-driven T-cell proliferation (P = .001), and TH2 cytokine production mediated by primed dendritic cells. iTR35 cells suppressed TH2 cell proliferation and cytokine production. In addition, allergen-driven IL-35 levels and iTR35 cell counts were increased in patients receiving SLIT (all, P < .001) and NACs (all, P < .001) compared with patients with SAR. CONCLUSION: IL-35 and iTR35 cells are potential novel immune regulators induced by SLIT. The clinical relevance of SLIT can be underscored by restoration of protective iTR35 cells.

Synchronous immune alterations mirror clinical response during allergen immunotherapy.

BACKGROUND: Three years of treatment with either sublingual or subcutaneous allergen immunotherapy has been shown to be effective and to induce long-term tolerance. The Gauging Response in Allergic Rhinitis to Sublingual and Subcutaneous Immunotherapy (GRASS) trial demonstrated that 2 years of treatment through either route was effective in suppressing the response to nasal allergen challenge, although it was insufficient for inhibition 1 year after discontinuation. OBJECTIVE: We sought to examine in the GRASS trial the time course of immunologic changes during 2 years of sublingual and subcutaneous immunotherapy and for 1 year after treatment discontinuation. METHODS: We performed multimodal immunomonitoring to assess allergen-specific CD4 T-cell properties in parallel with analysis of local mucosal cytokine responses induced by nasal allergen exposure and humoral immune responses that included IgE-dependent basophil activation and measurement of serum inhibitory activity for allergen-IgE binding to B cells (IgE-facilitated allergen binding). RESULTS: All 3 of these distinct arms of the immune response displayed significant and coordinate alterations during 2 years of allergen desensitization, followed by reversal at 3 years, reflecting a lack of a durable immunologic effect. Although frequencies of antigen-specific TH2 cells in peripheral blood determined by using HLA class II tetramer analysis most closely paralleled clinical outcomes, IgE antibody-dependent functional assays remained inhibited in part 1 year after discontinuation. CONCLUSION: Two years of allergen immunotherapy were effective but insufficient for long-term tolerance. Allergen-specific TH2 cells most closely paralleled the transient clinical outcome, and it is likely that recurrence of the T-cell drivers of allergic immunity abrogated the potential for durable tolerance. On the other hand, the persistence of IgE blocking antibody 1 year after discontinuation might be an early indicator of a protolerogenic mechanism.

Short-term subcutaneous grass pollen immunotherapy under the umbrella of anti-IL-4: A randomized controlled trial.

BACKGROUND: Allergen immunotherapy is currently the only disease-modifying treatment available for allergic rhinitis and allergic asthma. OBJECTIVES: We sought to evaluate the induction of sustained tolerance to allergen when anti-IL-4 was combined with a suboptimal course of grass pollen subcutaneous immunotherapy (SCIT) using the allergen-induced skin late-phase response (LPR) and exploratory immune monitoring as surrogate markers of therapeutic response. METHODS: In this randomized, double-blind, 3-group parallel design trial, 37 participants with seasonal allergic rhinitis received suboptimal SCIT (30,000 standardized quality units) in combination with anti-IL-4 (VAK694) and suboptimal SCIT (30,000 standardized quality units) plus placebo antibody or double placebo (placebo SCIT and placebo antibody) restricted to 13 weeks before the grass pollen season. The primary end point was the size of the LPR at 12 months. Exploratory end points included measures of the immunomodulatory activity of treatment by using IL-4 and IL-10 FluoroSpot assays, flow cytometry of T cells, and measurement of IgE, IgG4, and facilitated antigen binding. RESULTS: Both active treatment arms led to a substantial and sustained reduction of the LPR with no additional suppression with addition of anti-IL-4. Treatment with anti-IL-4 and SCIT compared with SCIT alone led to a sustained reduction in allergen-specific IL-4-producing cell counts (P < .01). Both active treatment arms led to induction of dual IL-4/IL-10-producing cells during the pollen season. CONCLUSION: The combination of anti-IL-4 with SCIT provided no additional benefit over SCIT alone in suppressing the allergen-induced skin LPR. A larger trial is needed to assess whether the observed ex vivo downregulation of TH2 responses might translate into clinical benefit.

Effect of 2 Years of Treatment With Sublingual Grass Pollen Immunotherapy on Nasal Response to Allergen Challenge at 3 Years Among Patients With Moderate to Severe Seasonal Allergic Rhinitis: The GRASS Randomized Clinical Trial.

Importance: Sublingual immunotherapy and subcutaneous immunotherapy are effective in seasonal allergic rhinitis. Three years of continuous treatment with subcutaneous immunotherapy and sublingual immunotherapy has been shown to improve symptoms for at least 2 years following discontinuation of treatment. Objective: To assess whether 2 years of treatment with grass pollen sublingual immunotherapy, compared with placebo, provides improved nasal response to allergen challenge at 3-year follow-up. Design, Setting, and Participants: A randomized double-blind, placebo-controlled, 3-parallel-group study performed in a single academic center, Imperial College London, of adult patients with moderate to severe seasonal allergic rhinitis (interfering with usual daily activities or sleep). First enrollment was March 2011, last follow-up was February 2015. Interventions: Thirty-six participants received 2 years of sublingual immunotherapy (daily tablets containing 15 µg of major allergen Phleum p 5 and monthly placebo injections), 36 received subcutaneous immunotherapy (monthly injections containing 20 µg of Phleum p 5 and daily placebo tablets) and 34 received matched double-placebo. Nasal allergen challenge was performed before treatment, at 1 and 2 years of treatment, and at 3 years (1 year after treatment discontinuation). Main Outcomes and Measures: Total nasal symptom scores (TNSS; range; 0 [best] to 12 [worst]) were recorded between 0 and 10 hours after challenge. The minimum clinically important difference for change in TNSS within an individual is 1.08. The primary outcome was TNSS comparing sublingual immunotherapy vs placebo at year 3. Subcutaneous immunotherapy was included as a positive control. The study was not powered to compare sublingual immunotherapy with subcutaneous immunotherapy. Results: Among 106 randomized participants (mean age, 33.5 years; 34 women [32.1%]), 92 completed the study at 3 years. In the intent-to-treat population, mean TNSS score for the sublingual immunotherapy group was 6.36 (95% CI, 5.76 to 6.96) at pretreatment and 4.73 (95% CI, 3.97 to 5.48) at 3 years, and for the placebo group, the score was 6.06 (95% CI, 5.23 to 6.88) at pretreatment and 4.81 (95% CI, 3.97 to 5.65) at 3 years. The between-group difference (adjusted for baseline) was -0.18 (95% CI, -1.25 to 0.90; [P = .75]). Conclusions and Relevance: Among patients with moderate to severe seasonal allergic rhinitis, 2 years of sublingual grass pollen immunotherapy was not significantly different from placebo in improving the nasal response to allergen challenge at 3-year follow-up. Trial Registration: clinicaltrials.gov Identifier: NCT01335139; EudraCT Number: 2010-023536-16.

Basophil expression of diamine oxidase: a novel biomarker of allergen immunotherapy response.

BACKGROUND: Immunotherapy inhibits basophil histamine release, but the assay is cumbersome, and no one has studied the effects of immunotherapy withdrawal. OBJECTIVE: Intracellular fluorochrome-labeled diamine oxidase (DAO) was used as a novel functional readout of basophil histamine release after immunotherapy. Results were compared with conventional basophil surface expression of activation markers. METHODS: Subcutaneous immunotherapy (SCIT)-treated patients (n = 14), sublingual immunotherapy (SLIT)-treated patients (n = 12), participants who completed 3 years of treatment with grass pollen sublingual immunotherapy (the SLIT-TOL group; n = 6), patients with untreated seasonal allergic rhinitis (SAR; n = 24), and nonatopic control subjects (n = 12) were studied. Intracellularly labeled DAO(+) and surface expression of CD203c(bright), CD63(+), and CD107a(+) on chemoattractant receptor-homologous molecule expressed on TH2 lymphocytes (CRTh2)-positive basophils were measured by means of flow cytometry. Serum IgG4 levels and serum inhibitory activity for IgE-allergen complex binding to B cells (IgE-FAB) and basophil histamine release were also determined. RESULTS: Proportions of allergen-stimulated DAO(+)CRTh2(+) basophils were higher in participants in the SCIT, SLIT, and SLIT-TOL groups (all P < .0001) compared with those in patients in the SAR group. Similarly, there were lower proportions of CRTh2(+) basophils expressing surface CD203c(bright) (all P < .001), CD63 (all P < .001), and CD107a (all P < .01). Rhinitis symptoms were lower in the SCIT, SLIT, and SLIT-TOL groups (P < .001) compared with those in the SAR group. Serum inhibitory activity for IgE-FAB and basophil histamine release were also significantly greater in all immunotherapy groups (P < .05) compared with the SAR group. CONCLUSION: These results support long-term clinical and immunologic tolerance during and after grass pollen immunotherapy. Intracellularly labeled DAO expression by basophils merits further investigation as a surrogate biomarker for monitoring efficacy and tolerance after immunotherapy.

Cytokine profiles in allergic rhinitis.

Allergic rhinitis, particularly seasonal allergic rhinitis, is considered a classic Th2-mediated disease, with important contributions to pathology by interleukins 4, 5 and 13. As such, allergic rhinitis is an excellent model for studying allergic inflammation, with findings potentially relevant to the mechanism of lower airways inflammation seen in allergic asthma. However, recent evidence has revealed roles for additional non-Th2 cytokines in asthma, including IL-17 family cytokines and epithelial-derived cytokines. Additionally, putative roles for epithelial-derived cytokines and innate lymphoid cells have been described in chronic rhinosinusitis with nasal polyps. Here, evidence for the involvement of different cytokines and cytokine groups in allergic rhinitis is considered.

Utility of silver birch and house dust mite extracts derived from licensed sublingual tablets for nasal allergen challenge.

BACKGROUND: Nasal allergen challenge (NAC) is used to investigate the effects of allergen exposure and assess treatment efficacy in allergic rhinitis (AR). This study aims to establish dose-responses to NAC using licensed silver birch (SB) pollen and house dust mite (HDM) sublingual tablets as sources of the allergen extracts in participants with AR. METHODS: Sixteen volunteers with HDM-induced perennial AR and 15 volunteers with SB pollen-induced seasonal rhinitis underwent a graded up-dosing NAC with extracts derived from HDM allergen (Acarizax®) and SB (Itulazax®) tablets, respectively. Total nasal symptom score (TNSS, range 0-12) and peak nasal inspiratory flow (PNIF) were recorded before, at 10 min and at the end of the NAC. The dose of each allergen that provoked a TNSS of at least 7 ("provoking dose 7") in most allergic participants was identified. NACs using the "provoking dose 7" were performed on 5 non-allergic individuals to test for irritant effects. The "provoking dose 7" of HDM extract was used in a subgroup of two SB allergic, non-HDM allergic, volunteers, and vice versa for SB extract, to test for allergen specificity of the responses. RESULTS: Most patients experienced a TNSS of at least 7/12 at a median concentration of 1500 AU/mL for both SB pollen and HDM. The average decline in PNIF at this dose was 63.15% for SB and 63.99% for HDM. NACs using the 1500 AU/mL concentrations were performed on 5 non-allergic individuals with no symptomatic or PNIF response. 1500 AU/mL of HDM extract produced no symptoms in SB allergics nor 1500 AU/mL SB extract in HDM allergics. CONCLUSION: For both SB and HDM extracts, the optimal allergen dose for NAC to cause a moderate-severity response ("provoking dose 7/12") was 1500 AU/mL. Licensed sublingual allergen tablets provide a readily available and inexpensive source of SB and HDM extracts for use in future interventional studies in AR.

Imaging of chronic rhinosinusitis with nasal polyps in the era of biological therapies.

PURPOSE OF REVIEW: Chronic rhinosinusitis (CRS) is a chronic inflammatory disorder of the sinonasal cavities classified into two major phenotypes: CRS with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP). The diagnosis of CRS is based on clinical symptoms associated with imaging and/or nasal endoscopy findings of mucosal inflammation. RECENT FINDINGS: Recently, novel biological therapies have emerged as therapeutic options for CRSwNP. Imaging is helpful in deciding whether surgery is likely to be beneficial and in guiding surgery. It can also help demonstrate a clinical response to medical therapy. However, specific guidelines concerning the role of imaging in CRwNP are lacking. SUMMARY: This article provides a comprehensive and critical multidisciplinary review of the role of conventional radiology, computed tomography (CT), and magnetic resonance imaging (MRI) in the diagnosis and characterization of CRSwNP. Since the complete characterization of nasal polyps on CT or MR images is very challenging, we provide a critical review of the best imaging methods and essential reporting elements used to assess nasal polyps.

Innate and adaptive immunity in allergic airway disease.

PURPOSE OF REVIEW: This article explores recent findings on the involvement of innate immunity in allergic airways disease, concentrating on allergic rhinitis. RECENT FINDINGS: We speculate on the ways in which environmental influences act to initiate inflammation and on how these may have altered in recent decades. Improved understanding of the mechanisms involved may reveal future possibilities for therapy. SUMMARY: The complex nature of immunity - both innate and acquired - in airways disease has implications for prevention and for therapy and requires further elucidation.

Neutrophil Extracellular Traps in Asthma: Friends or Foes?

Asthma is a chronic inflammatory disease characterized by variable airflow limitation and airway hyperresponsiveness. A plethora of immune and structural cells are involved in asthma pathogenesis. The roles of neutrophils and their mediators in different asthma phenotypes are largely unknown. Neutrophil extracellular traps (NETs) are net-like structures composed of DNA scaffolds, histones and granular proteins released by activated neutrophils. NETs were originally described as a process to entrap and kill a variety of microorganisms. NET formation can be achieved through a cell-death process, termed NETosis, or in association with the release of DNA from viable neutrophils. NETs can also promote the resolution of inflammation by degrading cytokines and chemokines. NETs have been implicated in the pathogenesis of various non-infectious conditions, including autoimmunity, cancer and even allergic disorders. Putative surrogate NET biomarkers (e.g., double-strand DNA (dsDNA), myeloperoxidase-DNA (MPO-DNA), and citrullinated histone H3 (CitH3)) have been found in different sites/fluids of patients with asthma. Targeting NETs has been proposed as a therapeutic strategy in several diseases. However, different NETs and NET components may have alternate, even opposite, consequences on inflammation. Here we review recent findings emphasizing the pathogenic and therapeutic potential of NETs in asthma.

Innate and Adaptive Immunity: ILC2 and Th2 Cells in Upper and Lower Airway Allergic Diseases.

Advances in our understanding of the immune system, with the recent discovery of a parallel set of innate T lymphocytes, the innate lymphocytes (ILCs), have led to a reassessment of the pathogenesis of allergic and eosinophilic airway disorders, including allergic rhinitis (AR), asthma, and chronic rhinosinusitis with nasal polyps. We review current understanding of both elements of type-2 inflammatory responses and their relative influence in these common conditions and consider possible impacts of this on treatment selection.