Long-Term Effectiveness of Anti-IL-4R Therapy Following Suboptimal Response to Anti-IL-5/5R Therapy in Severe Eosinophilic Asthma

BACKGROUND

Dupilumab is an anti-IL-4R monoclonal antibody (mAb) with proven efficacy in severe eosinophilic asthma (SEA). A suboptimal response to anti-IL-5/5R mAbs is seen in some patients with ongoing evidence of type 2 (T2) inflammation.

OBJECTIVE

To understand whether targeting IL-13 pathways with dupilumab in these patients may lead to better clinical outcomes.

METHODS

We performed a retrospective analysis of the extended clinical effectiveness of dupilumab up to 2 years of treatment in patients with SEA who had not responded adequately to anti-IL-5/5R biologics. The ability to achieve clinical remission and the change in the remission domains of exacerbation rate (AER), maintenance oral corticosteroid dose (mOCS), lung function (forced expiratory volume in 1 second), and asthma control (Asthma Control Questionnaire 6) were recorded.

RESULTS

Thirty-seven patients (mean age 41 years, 70% female) were included in the analysis. The mean (standard deviation) AER fell by almost 90% from 3.16 (1.28) at dupilumab initiation to 0.35 (0.72) after 1 year. The median (interquartile range) mOCS dose (n = 20) fell from 10 (5-25) mg to 0 (0-5) mg at 1 year, with 14 of 20 (70%) able to stop prednisolone altogether. Clinical remission was achieved in 16 of 37 (43%). Patients who achieved remission had a higher pre-IL-5/5R fractional exhaled nitric oxide (FeNO) level (85 [39-198] parts per billion [ppb] vs 75 [42-96] ppb, P = .03).

CONCLUSIONS

Significant improvements in clinical outcomes are possible after a switch to dupilumab in patients experiencing a suboptimal response to anti-IL-5/5R therapies. A higher FeNO in poor responders to anti-IL-5/5R who achieve remission with dupilumab is suggestive of an IL-13-driven subphenotype of T2-high asthma in which the eosinophil appears unlikely to play a key role in the disease pathogenesis.

Long-Term Effectiveness of Benralizumab in Eosinophilic Granulomatosis With Polyangiitis

BACKGROUND

Eosinophilic granulomatosis with polyangiitis (EGPA) is a multisystemic disease characterized by eosinophilic tissue inflammation. Benralizumab, an anti-IL-5 receptor (anti-IL-5R) monoclonal antibody, induces rapid depletion of eosinophils; its longer-term effect in EGPA is unknown.

OBJECTIVE

To assess the real-world effectiveness and clinical remission rates of anti-IL-5R therapy in EGPA.

METHODS

We performed a retrospective cohort analysis of patients with EGPA, who commenced treatment with benralizumab. Clinical remission, assessed at 1 year and 2 years after the initiation of benralizumab, was defined as an absence of active vasculitis (Birmingham Vasculitis Activity Score of 0) and an oral corticosteroid (OCS) dose of ≤4 mg/d of prednisolone. "Super-responders" were defined as patients in remission and free of any significant relapses (asthma or extrapulmonary) over the preceding 12 months. The corticosteroid-sparing capacity of benralizumab, patient-reported outcome measures, and characteristics associated with clinical remission and super-responder status were also analyzed.

RESULTS

A total of 70 patients completed at least 1 year of treatment with benralizumab, of whom 53 completed 2 years. Of 70 patients, 47 (67.1%) met the definition for clinical remission at 1 year, with a similar proportion in remission at 2 years. Excluding asthma-related relapses, 61 of 70 (87.1%) patients were relapse free at 1 year, and of the 53 who completed 2 years, 45 (84.9%) were relapse free. A total of 67.9% of patients no longer needed any OCS for disease control. No significant difference was seen between antineutrophilic cytoplasmic antibody (ANCA)-positive and ANCA-negative subgroups.

CONCLUSIONS

In this real-world setting of patients with EGPA, treatment with benralizumab was well tolerated and resulted in corticosteroid-free clinical remission for the majority of patients.

Type I conventional dendritic cells relate to disease severity in virus-induced asthma exacerbations

RATIONALE

Rhinoviruses are the major precipitant of asthma exacerbations and individuals with asthma experience more severe/prolonged rhinovirus infections. Concurrent viral infection and allergen exposure synergistically increase exacerbation risk. Although dendritic cells orchestrate immune responses to both virus and allergen, little is known about their role in viral asthma exacerbations.

OBJECTIVES

To characterize dendritic cell populations present in the lower airways, and to assess whether their numbers are altered in asthma compared to healthy subjects prior to infection and during rhinovirus-16 infection.

METHODS

Moderately-severe atopic asthmatic patients and healthy controls were experimentally infected with rhinovirus-16. Bronchoalveolar lavage was collected at baseline, day 3 and day 8 post infection and dendritic cells isolated using fluorescence activated cell sorting.

MEASUREMENTS AND MAIN RESULTS

Numbers of type I conventional dendritic cells, which cross prime CD8⁺ T helper cells and produce innate interferons, were significantly reduced in the lower airways of asthma patients compared to healthy controls at baseline. This reduction was associated serum IgE at baseline and with reduced numbers of CD8⁺ T helper cells and with increased viral replication, airway eosinophils and reduced lung function during infection. IgE receptor expression on lower airway plasmacytoid dendritic cells was significantly increased in asthma, consistent with a reduced capacity to produce innate interferons.

CONCLUSIONS

Reduced numbers of anti-viral type I conventional dendritic cells in asthma are associated with adverse outcomes during rhinovirus infection. This, with increased FcεR1α expression on lower airway plasmacytoid DCs could mediate the more permissive respiratory viral infection observed in asthma patients.

Pulmonary Innate Lymphoid Cell Responses during Rhinovirus-induced Asthma Exacerbations In Vivo: A Clinical Trial

Rationale Type 2 innate lymphoid cells (ILC2s) are significant sources of type 2 cytokines, which are implicated in the pathogenesis of asthma and asthma exacerbations. The role of ILC2s in virus-induced asthma exacerbations is not well-characterized. Objectives To characterize pulmonary ILC responses following experimental rhinovirus challenge in patients with moderate asthma and healthy subjects. Methods Patients with moderate asthma and healthy subjects were inoculated with rhinovirus-16, and underwent bronchoscopy at baseline, day 3 and day 8 post-inoculation. Pulmonary ILC1s and ILC2s were quantified in bronchoalveolar lavage (BAL) using flow cytometry. The ratio of BAL ILC2:ILC1 was assessed to determine their relative contributions to the clinical and immune response to rhinovirus challenge. Measurements and Main Results At baseline, ILC2s were significantly higher in patients with asthma than healthy subjects. At day 8, ILC2s significantly increased from baseline in both groups, which was significantly higher in asthma than in healthy subjects (all comparisons P<0.05). In healthy subjects, ILC1s increased from baseline at day 3 (P=0.001), while in patients with asthma, ILC1s increased from baseline at day 8 (P=0.042). Patients with asthma had significantly higher ILC2:ILC1 ratios at baseline (P=0.024) and day 8 (P=0.005). Increased ILC2:ILC1 ratio in asthma correlated with clinical exacerbation severity and type 2 cytokines in nasal mucosal lining fluid. Conclusions An ILC2-predominant inflammatory profile in asthma was associated with increased severity and duration of rhinovirus infection compared with healthy subjects, supporting the potential role of ILC2s in the pathogenesis of virus-induced asthma exacerbations. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT01773590.

Real-World Effectiveness of Anti-IL-5/5R Therapy in Severe Atopic Eosinophilic Asthma with Fungal Sensitization

BACKGROUND

Severe asthma with fungal sensitization (SAFS) is a complex clinical phenotype associated with poorly controlled type 2 inflammation and significant morbidity from both the disease itself and a high steroid burden.

OBJECTIVE

To assess the effectiveness of biologic therapies targeting eosinophilic inflammation in SAFS.

METHODS

We assessed the effectiveness of treatment with mepolizumab or benralizumab in patients with SAFS, and compared outcomes with patients with severe atopic asthma without fungal sensitization and patients with severe nonatopic asthma. Baseline clinical characteristics and clinical outcomes at 48 weeks were evaluated. A subgroup analysis was performed of patients who met the criteria for allergic bronchopulmonary aspergillosis (ABPA) rather than SAFS.

RESULTS

A total of 193 patients treated with mepolizumab (n = 63) or benralizumab (n = 130) were included. Patients with SAFS had higher baseline IgE level compared with patients with severe atopic asthma without fungal sensitization and severe nonatopic asthma (733 ± 837 IU/mL vs 338 ± 494 and 142 ± 171, respectively; both P < .001). There were no other significant baseline differences in clinical characteristics between groups. At 48 weeks, there were significant improvements in 6-item asthma control questionnaire score and exacerbation frequency, and reduction in maintenance oral corticosteroid dose across all groups (all P < .05). No significant between-group differences in outcomes were observed at 48 weeks. Patients with ABPA (n = 9) had a significant reduction in exacerbation frequency (P = .013) with treatment.

CONCLUSIONS

Treatment with eosinophil-targeting biologics led to improvements in exacerbation frequency, oral corticosteroid requirements, and patient-reported outcomes in patients with SAFS, with a reduction in exacerbations in the subgroup of patients with ABPA. These data highlight the potential clinical utility of targeting eosinophilic inflammation in SAFS and ABPA.

Profiling of H3K27Ac Reveals the Influence of Asthma on the Epigenome of the Airway Epithelium

Background

Asthma is a chronic airway disease driven by complex genetic–environmental interactions. The role of epigenetic modifications in bronchial epithelial cells (BECs) in asthma is poorly understood.

Methods

We piloted genome-wide profiling of the enhancer-associated histone modification H3K27ac in BECs from people with asthma (n = 4) and healthy controls (n = 3).

Results

We identified n = 4,321 (FDR < 0.05) regions exhibiting differential H3K27ac enrichment between asthma and health, clustering at genes associated predominately with epithelial processes (EMT). We identified initial evidence of asthma-associated Super-Enhancers encompassing genes encoding transcription factors (TP63) and enzymes regulating lipid metabolism (PTGS1). We integrated published datasets to identify epithelium-specific transcription factors associated with H3K27ac in asthma (TP73) and identify initial relationships between asthma-associated changes in H3K27ac and transcriptional profiles. Finally, we investigated the potential of CRISPR-based approaches to functionally evaluate H3K27ac-asthma landscape in vitro by identifying guide-RNAs capable of targeting acetylation to asthma DERs and inducing gene expression (TLR3).

Conclusion

Our small pilot study validates genome-wide approaches for deciphering epigenetic mechanisms underlying asthma pathogenesis in the airways.

Steroid-sparing effects of benralizumab in patients with eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis characterised by asthma, chronic rhinosinusitis and blood eosinophilia, which may be accompanied by neurological, cardiac, cutaneous and renal involvement [1]. Oral corticosteroids (OCS) are the most frequently used drugs to control eosinophilic inflammation and symptoms. Persistent symptoms or relapses are common, however, and many patients are at risk of developing long-term complications from systemic steroid therapy [2]. The ability of other immunosuppressant agents to achieve consistent disease control or to reduce maintenance OCS (mOCS) requirements appears to be limited [3].

Benralizumab reduces oral corticosteroid requirements in patients with EGPA and leads to improved patient-reported outcome measureshttps://bit.ly/2GI0vhf

Real-World Effectiveness of Benralizumab in Severe Eosinophilic Asthma

BACKGROUND

Benralizumab is an IL5-receptor monoclonal antibody licensed for the treatment of severe eosinophilic asthma (SEA). It has demonstrated efficacy in clinical trials in reducing asthma exacerbation rates and maintenance oral corticosteroids (mOCSs).

RESEARCH QUESTION

What is the real-world effectiveness of benralizumab and what baseline characteristics are associated with response to therapy?

STUDY DESIGN AND METHODS

We assessed outcomes in all SEA patients who began benralizumab treatment at our specialist center. At each dosing visit, exacerbation history, mOCS dose, spirometry, and Asthma Control Questionnaire (ACQ6) and Mini-Asthma Quality of Life Questionnaire (mAQLQ) scores were recorded. Response to treatment was defined as a reduction of ≥ 50% in annualized exacerbation rate (AER) or in mOCS dose after 48 weeks of treatment. Super response was defined as zero exacerbations and no mOCSs for asthma.

RESULTS

One hundred thirty patients were included in the analysis. At 48 weeks, a 72.8% reduction in AER was noted, from 4.92 ± 3.35 per year in the year preceding biologic treatment to 1.34 ± 1.71 per year (P < .001), including 57 patients (43.8%) who were exacerbation-free with benralizumab. In those receiving mOCSs (n = 74 [56.9%]), the median daily prednisolone dose fell from 10 mg (interquartile range, 5-20 mg) to 0 mg (interquartile range, 0-5 mg; P < .001), and 38 of 74 patients (51.4%) were able to discontinue mOCS therapy. Clinically and statistically significant improvements were found in ACQ6 scores, mAQLQ scores, and FEV₁. Overall, 51 patients (39%) met the super responder definition and 112 patients (86%) met the responder definition. The optimal regression model of super responders vs other responders included baseline characteristics associated with a strongly eosinophilic phenotype and less severe disease. Eighteen patients (13.8%) were nonresponders to benralizumab. Evidence of chronic airway infection was observed in 6 of 18 patients, and an increase in the blood eosinophil count consistent with the development of anti-drug antibodies was observed in 5 of 18 patients.

INTERPRETATION

In a large real-world SEA cohort, benralizumab led to significant improvements in all clinical outcome measures. A lack of response was seen in a minority of patients and should be a focus for future investigation.

Adherence to corticosteroids and clinical outcomes in mepolizumab therapy for severe asthma

INTRODUCTION

Inhaled corticosteroids (ICS) achieve disease control in the majority of asthmatic patients, although adherence to prescribed ICS is often poor. Patients with severe eosinophilic asthma may require treatment with oral corticosteroids (OCS) and/or biologic agents such as mepolizumab. It is unknown if ICS adherence changes on, or alters clinical response to, biologic therapy.

METHODS

We examined ICS adherence and clinical outcomes in OCS-dependent severe eosinophilic asthma patients who completed 1 year of mepolizumab therapy. The ICS medicines possession ratio (MPR) was calculated (the number of doses of ICS issued on prescription/expected number) for the year before and the year after biologic initiation. Good adherence was defined as MPR >0.75, intermediate 0.74-0.51 and poor <0.5. We examined outcomes after 12 months of biologic therapy, including OCS reduction and annualised exacerbation rate (AER), stratified by adherence to ICS on mepolizumab.

RESULTS

Out of 109 patients commencing mepolizumab, 91 who had completed 12 months of treatment were included in the final analysis. While receiving mepolizumab, 68% had good ICS adherence, with 16 (18%) having poor ICS adherence. ICS use within the cohort remained similar before (MPR 0.81±0.32) and during mepolizumab treatment (0.82±0.32; p=0.78). Patients with good adherence had greater reductions in OCS dose (median (interquartile range) OCS reduction 100 (74-100)% versus 60 (27-100)%; p=0.031) and exacerbations (AER change -2.1±3.1 versus 0.3±2.5; p=0.011) than those with poor adherence. Good ICS adherence predicted the likelihood of stopping maintenance OCS (adjusted OR 3.19, 95% CI 1.02-9.94; p=0.045).

CONCLUSION

ICS nonadherence is common in severe eosinophilic asthma patients receiving mepolizumab, and is associated with a lesser reduction in OCS requirements and AER.

Real-World Effectiveness and the Characteristics of a "Super-Responder" to Mepolizumab in Severe Eosinophilic Asthma

BACKGROUND

Mepolizumab was the first licensed anti-IL5 monoclonal antibody for severe eosinophilic asthma (SEA). To date there are few data to confirm its efficacy in the real-world setting or assessment of baseline characteristics associated with response.

RESEARCH QUESTION

How do patients with severe eosinophilic asthma respond to mepolizumab in the real world setting and which characteristics are associated with a super-response to this therapy?

STUDY DESIGN AND METHODS

We conducted a retrospective review of all patients who received at least 16 weeks of treatment with mepolizumab (100 mg subcutaneously) for SEA at our regional asthma center in the United Kingdom. Clinical data were collected at each 4-week visit. At 16, 24, and 52 weeks, patients were classified as "responders" or "nonresponders." A response was defined as ≥50% reduction in exacerbations; for patients whose condition requires maintenance oral corticosteroids (mOCS), a response was defined as ≥50% reduction in prednisolone dose. Super responders were defined as exacerbation-free and off mOCS at one year.

RESULTS

Ninety-nine patients were included in the analysis. Asthma exacerbations decreased from a baseline of 4.04 ± 2.57 to 1.86 ± 2.17 per year at one year (54% reduction; P < .001). Sixty-eight patients were receiving mOCS at the time of commencing mepolizumab. By one year, the daily median dose fell from 10 mg (interquartile range, 10 to 15) to 0 mg (interquartile range, 0 to 10; P < .001). Fifty-seven percent of them were able to discontinue mOCS; 72.7% (95% CI, 63.0 to 80.7) of the patients were classified as responders, and 28.3% (95% CI, 20.2 to 38.0) of the patients were classified as super responders. Baseline characteristics associated with responder and super responder status included the presence of nasal polyposis (P = .012), lower baseline Asthma Control Questionnaire 6 (P = .006), a lower BMI (P = .014), and, in those patients receiving mOCS, a significantly lower prednisolone dose at baseline (P = .005). At 16 weeks, the one-year responder status was correctly identified in 80.8% patients; by 24 weeks, this status rose to 92.9%.

INTERPRETATION

In a real-world SEA cohort, treatment with mepolizumab reduced exacerbation frequency and mOCS requirements. Nasal polyposis, a lower BMI, and a lower maintenance prednisolone requirement at baseline were associated with better outcomes. Twelve-month response was identifiable in >90% of patients by week 24.

Epitope-specific airway-resident CD4+ T cell dynamics during experimental human RSV infection

BACKGROUNDRespiratory syncytial virus (RSV) is an important cause of acute pulmonary disease and one of the last remaining major infections of childhood for which there is no vaccine. CD4+ T cells play a key role in antiviral immunity, but they have been little studied in the human lung.METHODSHealthy adult volunteers were inoculated i.n. with RSV A Memphis 37. CD4+ T cells in blood and the lower airway were analyzed by flow cytometry and immunohistochemistry. Bronchial soluble mediators were measured using quantitative PCR and MesoScale Discovery. Epitope mapping was performed by IFN-γ ELISpot screening, confirmed by in vitro MHC binding.RESULTSActivated CD4+ T cell frequencies in bronchoalveolar lavage correlated strongly with local C-X-C motif chemokine 10 levels. Thirty-nine epitopes were identified, predominantly toward the 3' end of the viral genome. Five novel MHC II tetramers were made using an immunodominant EFYQSTCSAVSKGYL (F-EFY) epitope restricted to HLA-DR4, -DR9, and -DR11 (combined allelic frequency: 15% in Europeans) and G-DDF restricted to HLA-DPA1*01:03/DPB1*02:01 and -DPA1*01:03/DPB1*04:01 (allelic frequency: 55%). Tetramer labeling revealed enrichment of resident memory CD4+ T (Trm) cells in the lower airway; these Trm cells displayed progressive differentiation, downregulation of costimulatory molecules, and elevated CXCR3 expression as infection evolved.CONCLUSIONSHuman infection challenge provides a unique opportunity to study the breadth of specificity and dynamics of RSV-specific T-cell responses in the target organ, allowing the precise investigation of Trm recognizing novel viral antigens over time. The new tools that we describe enable precise tracking of RSV-specific CD4+ cells, potentially accelerating the development of effective vaccines.TRIAL REGISTRATIONClinicalTrials.gov NCT02755948.FUNDINGMedical Research Council, Wellcome Trust, National Institute for Health Research.

Mucosal Type 2 Innate Lymphoid Cells Are a Key Component of the Allergic Response to Aeroallergens

RATIONALE

Newly characterized type 2 innate lymphoid cells (ILC2s) display potent type 2 effector functionality; however, their contribution to allergic airways inflammation and asthma is poorly understood. Mucosal biopsy used to characterize the airway mucosa is invasive, poorly tolerated, and does not allow for sequential sampling.

OBJECTIVES

To assess the role of ILC2s during nasal allergen challenge in subjects with allergic rhinitis using novel noninvasive methodology.

METHODS

We used a human experimental allergen challenge model, with flow cytometric analysis of nasal curettage samples, to assess the recruitment of ILC2s and granulocytes to the upper airways of subjects with atopy and healthy subjects after allergen provocation. Soluble mediators in the nasal lining fluid were measured using nasosorption.

MEASUREMENTS AND MAIN RESULTS

After an allergen challenge, subjects with atopy displayed rapid induction of upper airway symptoms, an enrichment of ILC2s, eosinophils, and neutrophils, along with increased production of IL-5, prostaglandin D2, and eosinophil and T-helper type 2 cell chemokines compared with healthy subjects. The most pronounced ILC2 recruitment was observed in subjects with elevated serum IgE and airway eosinophilia.

CONCLUSIONS

The rapid recruitment of ILC2s to the upper airways of allergic patients with rhinitis, and their association with key type 2 mediators, highlights their likely important role in the early allergic response to aeroallergens in the airways. The novel methodology described herein enables the analysis of rare cell populations from noninvasive serial tissue sampling.

A Comprehensive Evaluation of Nasal and Bronchial Cytokines and Chemokines Following Experimental Rhinovirus Infection in Allergic Asthma: Increased Interferons (IFN-γ and IFN-λ) and Type 2 Inflammation (IL-5 and IL-13)

Background

Rhinovirus infection is a major cause of asthma exacerbations.

Objectives

We studied nasal and bronchial mucosal inflammatory responses during experimental rhinovirus-induced asthma exacerbations.

Methods

We used nasosorption on days 0, 2–5 and 7 and bronchosorption at baseline and day 4 to sample mucosal lining fluid to investigate airway mucosal responses to rhinovirus infection in patients with allergic asthma (n = 28) and healthy non-atopic controls (n = 11), by using a synthetic absorptive matrix and measuring levels of 34 cytokines and chemokines using a sensitive multiplex assay.

Results

Following rhinovirus infection asthmatics developed more upper and lower respiratory symptoms and lower peak expiratory flows compared to controls (all P < 0.05). Asthmatics also developed higher nasal lining fluid levels of an anti-viral pathway (including IFN-γ, IFN-λ/IL-29, CXCL11/ITAC, CXCL10/IP10 and IL-15) and a type 2 inflammatory pathway (IL-4, IL-5, IL-13, CCL17/TARC, CCL11/eotaxin, CCL26/eotaxin-3) (area under curve day 0–7, all P < 0.05). Nasal IL-5 and IL-13 were higher in asthmatics at day 0 (P < 0.01) and levels increased by days 3 and 4 (P < 0.01). A hierarchical correlation matrix of 24 nasal lining fluid cytokine and chemokine levels over 7 days demonstrated expression of distinct interferon-related and type 2 pathways in asthmatics. In asthmatics IFN-γ, CXCL10/IP10, CXCL11/ITAC, IL-15 and IL-5 increased in bronchial lining fluid following viral infection (all P < 0.05).

Conclusions

Precision sampling of mucosal lining fluid identifies robust interferon and type 2 responses in the upper and lower airways of asthmatics during an asthma exacerbation. Nasosorption and bronchosorption have potential to define asthma endotypes in stable disease and at exacerbation.

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Following rhinovirus infection asthmatics have increased interferons and type 2 inflammation in airway mucosal lining fluid.

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Nasosorption cytokines and chemokines showed distinct pathways of interferon and type 2 inflammation in asthma.

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Precision mucosal sampling has potential for stratifying molecular endotypes of asthma.

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Validation of nasosorption and bronchosorption will be required for selection of asthmatics for therapy with biologics.

Experimental human rhinovirus (HRV) infection causes more severe upper and lower respiratory tract symptoms in allergic asthmatics than in healthy controls. There is greater induction of cytokines and chemokines in nasal and bronchial mucosal lining fluid (MLF) of asthmatics: with distinct pathways of type 2 and anti-viral/regulatory inflammation.

Subject to further validation, analysis of MLF may prove useful in stratification of patients with asthma, and the definition of molecular endotypes.

Interpretation

Nasosorption and bronchosorption are precision sampling methods with potential for widespread application in respiratory and other mucosal diseases (e.g. gastrointestinal diseases).

Biomarkers identified in nasosorption and bronchosorption samples will need to be validated compared to established airway sampling methods, in a range of asthma phenotypes, and with current and novel therapies.

Identification of novel macrolides with antibacterial, anti-inflammatory and type I and III IFN-augmenting activity in airway epithelium

BACKGROUND

Exacerbations of asthma and COPD are triggered by rhinoviruses. Uncontrolled inflammatory pathways, pathogenic bacterial burden and impaired antiviral immunity are thought to be important factors in disease severity and duration. Macrolides including azithromycin are often used to treat the above diseases, but exhibit variable levels of efficacy. Inhaled corticosteroids are also readily used in treatment, but may lack specificity. Ideally, new treatment alternatives should suppress unwanted inflammation, but spare beneficial antiviral immunity.

METHODS

In the present study, we screened 225 novel macrolides and tested them for enhanced antiviral activity against rhinovirus, as well as anti-inflammatory activity and activity against Gram-positive and Gram-negative bacteria. Primary bronchial epithelial cells were grown from 10 asthmatic individuals and the effects of macrolides on rhinovirus replication were also examined. Another 30 structurally similar macrolides were also examined.

RESULTS

The oleandomycin derivative Mac5, compared with azithromycin, showed superior induction (up to 5-fold, EC50 = 5-11 μM) of rhinovirus-induced type I IFNβ, type III IFNλ1 and type III IFNλ2/3 mRNA and the IFN-stimulated genes viperin and MxA, yet had no effect on IL-6 and IL-8 mRNA. Mac5 also suppressed rhinovirus replication at 48 h, proving antiviral activity. Mac5 showed antibacterial activity against Gram-positive Streptococcus pneumoniae; however, it did not have any antibacterial properties compared with azithromycin when used against Gram-negative Escherichia coli (as a model organism) and also the respiratory pathogens Pseudomonas aeruginosa and non-typeable Haemophilus influenzae. Further non-toxic Mac5 derivatives were identified with various anti-inflammatory, antiviral and antibacterial activities.

CONCLUSIONS

The data support the idea that macrolides have antiviral properties through a mechanism that is yet to be ascertained. We also provide evidence that macrolides can be developed with anti-inflammatory, antibacterial and antiviral activity and show surprising versatility depending on the clinical need.

RSV-specific airway resident memory CD8+ T cells and differential disease severity after experimental human infection

In animal models, resident memory CD8+ T (Trm) cells assist in respiratory virus elimination but their importance in man has not been determined. Here, using experimental human respiratory syncytial virus (RSV) infection, we investigate systemic and local virus-specific CD8+ T-cell responses in adult volunteers. Having defined the immunodominance hierarchy, we analyse phenotype and function longitudinally in blood and by serial bronchoscopy. Despite rapid clinical recovery, we note surprisingly extensive lower airway inflammation with persistent viral antigen and cellular infiltrates. Pulmonary virus-specific CD8+ T cells display a CD69+CD103+ Trm phenotype and accumulate to strikingly high frequencies into convalescence without continued proliferation. While these have a more highly differentiated phenotype, they express fewer cytotoxicity markers than in blood. Nevertheless, their abundance before infection correlates with reduced symptoms and viral load, implying that CD8+ Trm cells in the human lung can confer protection against severe respiratory viral disease when humoral immunity is overcome.

Respiratory syncytial virus (RSV) is a common cause of respiratory tract infections. Here the authors analyse cellular immune responses of individuals experimentally infected with RSV and reveal the presence of high frequencies of virus- specific resident memory CD8⁺ T cells in the airway, which correlate with improved viral control.

IL-33-dependent type 2 inflammation during rhinovirus-induced asthma exacerbations in vivo

RATIONALE

Rhinoviruses are the major cause of asthma exacerbations; however, its underlying mechanisms are poorly understood. We hypothesized that the epithelial cell-derived cytokine IL-33 plays a central role in exacerbation pathogenesis through augmentation of type 2 inflammation.

OBJECTIVES

To assess whether rhinovirus induces a type 2 inflammatory response in asthma in vivo and to define a role for IL-33 in this pathway.

METHODS

We used a human experimental model of rhinovirus infection and novel airway sampling techniques to measure IL-4, IL-5, IL-13, and IL-33 levels in the asthmatic and healthy airways during a rhinovirus infection. Additionally, we cultured human T cells and type 2 innate lymphoid cells (ILC2s) with the supernatants of rhinovirus-infected bronchial epithelial cells (BECs) to assess type 2 cytokine production in the presence or absence of IL-33 receptor blockade.

MEASUREMENTS AND MAIN RESULTS

IL-4, IL-5, IL-13, and IL-33 are all induced by rhinovirus in the asthmatic airway in vivo and relate to exacerbation severity. Further, induction of IL-33 correlates with viral load and IL-5 and IL-13 levels. Rhinovirus infection of human primary BECs induced IL-33, and culture of human T cells and ILC2s with supernatants of rhinovirus-infected BECs strongly induced type 2 cytokines. This induction was entirely dependent on IL-33.

CONCLUSIONS

IL-33 and type 2 cytokines are induced during a rhinovirus-induced asthma exacerbation in vivo. Virus-induced IL-33 and IL-33-responsive T cells and ILC2s are key mechanistic links between viral infection and exacerbation of asthma. IL-33 inhibition is a novel therapeutic approach for asthma exacerbations.

Smoking cessation in COPD causes a transient improvement in spirometry and decreases micronodules on high-resolution CT imaging

BACKGROUND

Smoking cessation is of major importance for all smokers; however, in patients with COPD, little information exists on how smoking cessation influences lung function and high-resolution CT (HRCT) scan appearances.

METHODS

In this single-center study, we performed screening spirometry in a group of heavy smokers aged 40 to 80 years (N = 358). We then studied the effects of smoking cessation in two groups of selected subjects: smokers with COPD (n = 38) and smokers with normal spirometry (n = 55). In parallel to subjects undergoing smoking cessation, we studied a control group of nonsmokers (n = 19).

RESULTS

Subjects with COPD who quit smoking had a marked, but transient improvement in FEV1 at 6 weeks (184 mL, n = 17, P < .01) that was still present at 12 weeks (81 mL, n = 17, P < .05) and only partially maintained at 1 year. In contrast, we saw improvement in the transfer factor of lung for carbon monoxide at 6 weeks in both subjects with COPD who quit smoking (0.47 mmol/min/kPa, n = 17, P < .01) and subjects who quit smoking with normal spirometry (0.40 mmol/min/kPa, n = 35, P < .01). An upper-zone single HRCT image slice reliably identified emphysema at baseline in 74% of smokers with COPD (28 of 38) and 29% of healthy smokers (16 of 55). Smoking cessation had no significant effect on the appearances of emphysema but decreased the presence of micronodules on HRCT imaging.

CONCLUSIONS

Cigarette smoking causes extensive lung function and HRCT image abnormalities, even in patients with normal spirometry. Smoking cessation has differential effects on lung function (FEV1 and gas transfer) and features on HRCT images (emphysema and micronodules). Cessation of smoking in patients with COPD causes a transient improvement in FEV1 and decreases the presence of micronodules, offering an opportunity for concomitant therapy during smoking cessation to augment these effects. Smoking cessation at the earliest possible opportunity is vital to minimize permanent damage to the lungs.

Anti-viral agents: potential utility in exacerbations of asthma

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Respiratory virus infections are the single greatest precipitants of asthma exacerbations.

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Current treatment options for AE are limited and have developed little in recent years.

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Development of effective anti-viral treatments remains a key target for therapeutic intervention.

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Approaches include therapies that either target the virus or boost host response to the virus.

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New clinical studies are needed to further our understanding of the mechanisms of virus induced asthma exacerbation.

Asthma is the most common chronic respiratory disease and its prevalence is on the increase. Respiratory viral infections in early life have been suggested to increase the risk of development of asthma in later life and virus infection remains the single greatest precipitant of asthma exacerbations. The development of effective anti-viral treatments remains a key target for therapeutic intervention. Here we discuss the role of respiratory viral infection in asthma exacerbation and highlight current and potential anti-viral agents and their mechanisms of action.

A comparison between two strategies for monitoring hepatic function during antituberculous therapy

RATIONALE

The optimum strategy for monitoring liver function during antituberculous therapy is unclear.

OBJECTIVES

To assess the value of the American Thoracic Society risk-factor approach for predicting drug-induced liver injury and to compare with a uniform policy of liver function testing in all patients at 2 weeks.

METHODS

We conducted an observational study of adult patients undergoing therapy for active tuberculosis at a tertiary center. All patients had alanine transferase measurement at baseline and 2 weeks following commencement of therapy. Sensitivity, specificity, and positive and negative predictive values were used to assess strategies.

MEASUREMENTS AND MAIN RESULTS

There were 288 patients included, and 21 (7.3%) developed drug-induced liver injury (57.1% "early" at 2 wk and 42.9% "late," after 2 wk). There were increased rates of individuals with HIV infection in the early drug-induced liver injury group compared with no drug-induced liver injury and late drug-induced liver injury groups (33% vs. 7.1% vs. 0%; P = 0.004). The American Thoracic Society algorithm had a sensitivity and specificity of 66.7 and 65.6%, respectively, for prediction of early and 22.2% and 63.7% for late drug-induced liver injury. The uniform monitoring policy had poor sensitivity but better specificity (22.2 and 82.1%) for prediction of late drug-induced liver injury.

CONCLUSIONS

In our urban, ethnically diverse population, a risk-factor approach is neither sensitive nor specific for prediction of drug-induced liver injury. A uniform policy of liver function testing at 2 weeks is useful for prompt identification of a subgroup who develop early drug-induced liver injury and may offer better specificity in ruling out late drug-induced liver injury.

Post-bronchoscopy sputum: improving the diagnostic yield in smear negative pulmonary TB

INTRODUCTION

Patients with suspected active Pulmonary Tuberculosis (PTB) who are Acid-Fast Bacilli (AFB) smear negative or non-productive of sputum may undergo bronchoalveolar lavage. However, post-bronchoscopy sputum (PBS) sampling is not routine. The aim of this study was to establish the potential diagnostic value of PBS sampling.

METHODS

A retrospective study of patients attending a London University hospital with microbiologically confirmed PTB between January 2004 and December 2010. Patients who were AFB smear negative or non-productive of sputum were eligible if sputum sampling was performed within 7 days of bronchoscopy.

RESULTS

Over the study period, 236 patients had microbiologically confirmed smear negative PTB of which 57 patients were eligible for the study. 15 patients (26.3%) were infected with HIV. 19 patients (33.3%) converted to AFB sputum smear positivity post-bronchoscopy and 5 patients (8.8%) were exclusively AFB sputum smear positive on PBS microscopy. Mycobacterium tuberculosis was cultured from the PBS of 43 patients (75.4%) and of these, 4 (7.0%) were exclusively PBS culture positive.

CONCLUSION

PBS analysis can provide a simple method of rapidly diagnosing pulmonary tuberculosis. In this cohort, M. tuberculosis culture yield was increased by 7% through PBS sampling. This study has important infection control implications with nearly one third of patients becoming more infectious after bronchoscopy.