Allergen Immunotherapy for Asthma.

Allergen immunotherapy is a disease-modifying treatment for IgE-mediated allergies reducing disease burden and symptoms in patients with allergic rhinitis, with or without asthma. The growing evidence that allergen immunotherapy also has the potential to facilitate achieving asthma control in patients with allergic asthma resulted in its acknowledgment by international bodies (Global Initiative for Asthma and European Academy of Allergy and Clinical Immunology) as add-on treatment for mild/moderate asthma. Although there have been promising developments in biomarkers for patient selection and for allergen immunotherapy efficacy evaluation in patients with asthma, a lot more data are still required.

Standardization of clinical outcomes used in allergen immunotherapy in allergic asthma: An EAACI position paper.

INTRODUCTION: In allergic asthma patients, one of the more common phenotypes might benefit from allergen immunotherapy (AIT) as add-on intervention to pharmacological treatment. AIT is a treatment with disease-modifying modalities, the evidence for efficacy is based on controlled clinical trials following standardized endpoint measures. However, so far there is a lack of a consensus for asthma endpoints in AIT trials. The aim of a task force (TF) of the European Academy of Allergy and Clinical Immunology (EAACI) is evaluating several outcome measures for AIT in allergic asthma. METHODS: The following domains of outcome measures in asthmatic patients have been evaluated for this position paper (PP): (i) exacerbation rate, (ii) lung function, (iii) ICS withdrawal, (iv) symptoms and rescue medication use, (v) questionnaires (PROMS), (vi) bronchial/nasal provocation, (vii) allergen exposure chambers (AEC) and (viii) biomarkers. RESULTS: Exacerbation rate can be used as a reliable objective primary outcome; however, there is limited evidence due to different definitions of exacerbation. The time after ICS withdrawal to first exacerbation is considered a primary outcome measure. Besides, the advantages and disadvantages and clinical implications of further domains of asthma endpoints in AIT trials are elaborated in this PP. CONCLUSION: This EAACI-PP aims to highlight important aspects of current asthma measures by critically evaluating their applicability for controlled trials of AIT.

Effect of bariatric surgery on lung function and asthma control after 8 years of follow-up.

Background: Bariatric surgery has a proven beneficial effect on asthma symptoms and lung function in patients with class III obesity and asthma. The effects of bariatric surgery on asthma control and small airway function persist for at least 12 months after bariatric surgery. However, long-term follow-up data are lacking. Objectives: To evaluate the very-long term effects of bariatric surgery on asthma symptoms and lung function. Methods: In a prospective, longitudinal follow-up study, we planned an 8-year follow-up visit for patients previously included in the OBAS 1.0 trial, which evaluated the effects of bariatric surgery on asthma control and lung function in patients with asthma and class III obesity in The Netherlands. Results: Fifteen of 78 patients from the OBAS trial completed the 8-year follow-up visit. Nine patients underwent bariatric surgery, and six patients did not. After 8 years of follow-up, asthma control (Asthma Control Questionnaire [ACQ] score at 12 months of 0,4 versus an ACQ score of 0.7 at 8 years of follow-up; p = 0.075) and small airway function (R5-R20 (frequency-dependent resistance at 5Hz-20Hz); score at 12 months of 0,25 versus an ACQ score of 0.07 at 8 years of follow-up; p = 0.345) remained clinically stable compared with 12 months of follow-up. Patients who underwent bariatric surgery had a statistically significant weight regain between 12 months of follow-up and 8 years of follow-up (median [interquartile range] body mass index 30.2 kg/m² [23.9-43.4 kg/m²] versus 32.3 kg/m² [24.0-36.4 kg/m²]; p = 0.025). However, the impact of weight regain on asthma control, and asthma quality of life was clinically insignificant (ACQ, ß (regression coefficient) = 0.04; 95% Confidence Interval [0.02; 0.06]; p < 0.001; and AQLQ; ß = -0.04 CI [-0.07; -0.009]; p = 0.013). Conclusion: These results emphasize the importance of bariatric surgery in treating obesity-related asthma.

Efficacy and safety of dupilumab as add-on therapy for patients with severe asthma: A real-world Dutch cohort study.

BACKGROUND: Dupilumab as add-on treatment for severe uncontrolled asthma (SA) has shown to be effective and safe by phase-III-trials. Real-world data on clinical efficacy and safety is limited. OBJECTIVE: We aim to investigate the efficacy and safety of dupilumab as add-on therapy for SA in a real-world cohort. MATERIAL AND METHODS: The primary endpoint was annually exacerbation-rate (AER). Secondary outcomes were maintenance oral corticosteroid (mOCS) dependency, asthma control (ACQ-5), pulmonary function (FEV1), quality of life (AQLQ) and frequency of reported adverse events (AEs). RESULTS: Overall, 148 patients were included. Median AER [IQR] reduced from 4.00 [2.00-5.00] at baseline to 1.00 [0.00-2.00] at 12 months (p < 0.001). mOCS-dependency reduced from 39.9% of the patients at baseline, to 20.3% at 6 months and to 14.9% at 12 months (p < 0.001). Median ACQ improved from 3.00 [2.00-3.80] at baseline to 1.80 [0.60-2.95] after 6 months and to 1.40 [0.20-2.60] after 12 months (p < 0.001). Median FEV1 (L) improved from 2.21 [1.58-2.85] to 2.50 [2.00-3.06] at 6 months and to 2.51 [1.88-3.04] after 12 months (p < 0.001). The outcomes improved most in subgroups with high eosinophils (≥300/µL) or FeNO (≥50 ppb) at baseline. AEs were reported by 45.3% (67/148), of which headache was most frequent. CONCLUSIONS: This study indicates that dupilumab as add-on therapy for SA is associated with significant improvements in exacerbation-rate, mOCS-dependency, asthma control, pulmonary function, and quality of life. These results are in line with those of previous phase-III-trials.

Alpine altitude climate treatment for severe and uncontrolled asthma: An EAACI position paper.

Currently available European Alpine Altitude Climate Treatment (AACT) programs combine the physical characteristics of altitude with the avoidance of environmental triggers in the alpine climate and a personalized multidisciplinary pulmonary rehabilitation approach. The reduced barometric pressure, oxygen pressure, and air density, the relatively low temperature and humidity, and the increased UV radiation at moderate altitude induce several physiological and immunological adaptation responses. The environmental characteristics of the alpine climate include reduced aeroallergens such as house dust mites (HDM), pollen, fungi, and less air pollution. These combined factors seem to have immunomodulatory effects controlling pathogenic inflammatory responses and favoring less neuro-immune stress in patients with different asthma phenotypes. The extensive multidisciplinary treatment program may further contribute to the observed clinical improvement by AACT in asthma control and quality of life, fewer exacerbations and hospitalizations, reduced need for oral corticosteroids (OCS), improved lung function, decreased airway hyperresponsiveness (AHR), improved exercise tolerance, and improved sinonasal outcomes. Based on observational studies and expert opinion, AACT represents a valuable therapy for those patients irrespective of their asthma phenotype, who cannot achieve optimal control of their complex condition despite all the advances in medical science and treatment according to guidelines, and therefore run the risk of falling into a downward spiral of loss of physical and mental health. In the light of the observed rapid decrease in inflammation and immunomodulatory effects, AACT can be considered as a natural treatment that targets biological pathways.

STOP: an open label crossover trial to study ICS withdrawal in patients with a combination of obesity and low-inflammatory asthma and evaluate its effect on asthma control and quality of life.

BACKGROUND: Asthma patients with obesity often have a high disease burden, despite the use of high-dose inhaled corticosteroids (ICS). In contrast to asthmatics with normal weight, the efficacy of ICS in patients with obesity and asthma is often relatively low. Meanwhile, patients do suffer from side effects, such as weight gain, development of diabetes, cataract, or high blood pressure. The relatively poor response to ICS might be explained by the low prevalence of type 2 inflammatory patterns (T2-low) in patients with asthma and obesity. T2-low inflammation is characterized by low eosinophilic count, low Fractional exhaled NO (FeNO), no clinically allergy-driven asthma, and no need for maintenance oral corticosteroids (OCS). We aim to study whether ICS can be safely withdrawn in patients with T2-low asthma and obesity while maintaining an equal level of asthma control. Secondary outcomes focus on the prevalence of 'false-negative' T2-low phenotypes (i.e. T2-hidden) and the effect of ICS withdrawal on parameters of the metabolic syndrome. This study will lead to a better understanding of this poorly understood subgroup and might find new treatable traits. METHODS: The STOP trial is an investigator-initiated, multicenter, non-inferiority, open-label, crossover study aiming to assess whether ICS can be safely withdrawn in adults aged 17-75 years with T2-low asthma and obesity (body mass index (BMI) ≥ 30 kg/m2). Patients will be randomly divided into two arms (both n = 60). One arm will start with fixed-dose ICS (control group) and one arm will taper and subsequently stop ICS (intervention group). Patients in the intervention group will remain ICS naïve for ten weeks. After a washout of 4 weeks, patients will crossover to the other study arm. The crossover study takes 36 weeks to complete. Patients will be asked to participate in the extension study, to investigate the long-term metabolic benefits of ICS withdrawal. DISCUSSION: This study yields valuable data on ICS tapering in patients with T2-low asthma and obesity. It informs future guidelines and committees on corticosteroid-sparing algorithms in these patients. Trial registration Netherlands Trial Register, NL8759, registered 2020-07-06, https://www.trialregister.nl/trial/8759 . Protocol version and date: version 2.1, 20 November 2020.

A pilot study into bosentan (Tracleer®) as an immunomodulating agent in patients with Behçet's disease.

BACKGROUND: Behçet's disease (BD) is an auto-inflammatory vasculitis characterized by aphthous oro-genital ulcers, inflammatory skin changes and uveitis. Treatment is mainly immunosuppressive. Interestingly, elevated endotheline-1 (ET-1) levels suggest a possible beneficial effect of treatment with an ET-1 receptor antagonist. OBJECTIVE: The aim of our study was to investigate the possible beneficial effect of the ET-1 inhibitor bosentan. METHODS: We performed a prospective double-blind placebo controlled pilot study into the effect and safety of bosentan in BD patients. Disease activity was measured using the Behçet Disease Current Activity Form. The primary objective of the study was to determine whether bosentan is therapeutically effective in patients with BD. Secondary endpoints were safety, tapering of medication and the effect of bosentan on possible disease activity markers such as ET-1, circulating endothelial cells (CECs), soluble interleukin-2 receptor (sIL2R) and cytokine levels. RESULTS: Ten patients were randomized to either bosentan or placebo. Overall, no effect on disease activity was observed, although one patient responded clinically and continued treatment after the study period. Despite one SAE, bosentan seems safe to use. No effect on tapering of medication, CECs, sIL2R and cytokine levels was found. In the bosentan group, ET-1 levels were elevated during the treatment period, with no correlation with disease activity. CONCLUSIONS: Although this is a small pilot study, bosentan appears to be safe in BD patients. One patient had a durable and significant clinical response. Our observations should be confirmed and extended in a larger patient cohort to be of significant impact in the treatment options for BD.

Mepolizumab add-on therapy in a real world cohort of patients with severe eosinophilic asthma: response rate, effectiveness, and safety.

Introduction: Severe eosinophilic asthma is an incapacitating disease. Mepolizumab, a humanized anti-interleukin-5 monoclonal antibody, proved to be effective as an add-on therapy in patients with severe eosinophilic asthma. However, only data from randomized controlled trials are available and real world data are lacking.Methods: A retrospective observational longitudinal study was conducted in a real world cohort of patients with severe eosinophilic asthma treated with mepolizumab. The primary objective was to determine response rate, based on a global evaluation of treatment effectiveness by the treating pulmonologist. Secondary objectives were to assess exacerbation frequency, systemic maintenance glucocorticoid usage, Asthma Control Questionnaire (ACQ), lung function, and adverse events.Results: Seventy-eight patients were included. Treatment with mepolizumab was considered beneficial and was therefore continued in 75.6% of patients 12 months from the initiation of mepolizumab. The most common reason for drop-out was insufficient response. Secondary objectives: 12 months from the initiation of mepolizumab there was a decrease of 3.2 (CI 2.5-4.1; p < 0.001) severe asthma exacerbations per year, a decrease of ACQ of 0.80 points (CI 0.49-1.12; p < 0.001), and an increase of 3.7 (CI 0.3-7.2; p = 0.034) percent of predicted FEV1 compared to baseline. At baseline 51.3% of patients were treated with systemic glucocorticoid maintenance therapy, compared to 15.4% (p < 0.001) of patients 12 months from the initiation of mepolizumab. No serious adverse events considered to be related to mepolizumab were reported.Conclusion: This study confirms that mepolizumab add-on therapy is effective and safe in a real world cohort of patients with severe eosinophilic asthma.

[Air pollution: a determinant for COVID-19?] / Luchtverontreiniging: een determinant voor COVID-19?

Preliminary data from the Wuhan area in China, Northern Italy and specific areas in the United States suggest a correlation between the severity of the pandemic with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19, and air pollution. Observations in the Netherlands are in line with these data. COVID-19 struck hard in the eastern part of the province of Brabant, where levels of fine particulate matter and ammonia are relatively high due to intensive livestock farming. Mechanisms by which air pollution might facilitate SARS-CoV-2 infection include a possible link between upregulation of the angiotensin converting enzyme receptor by air pollution and the host being prone to more severe COVID-19. Although the data are not yet peer-reviewed and the potential association does not necessarily imply causality, these data do stress the need for further investigation. If air pollution plays a role in the severity of the corona pandemic, more vigorous legislation concerning air quality is pivotal.

Behçet's Disease Under Microbiotic Surveillance? A Combined Analysis of Two Cohorts of Behçet's Disease Patients.

Background: In Behçet's disease (BD), an auto-inflammatory vasculitis, an unbalanced gut microbiota can contribute to pro-inflammatory reactions. In separate studies, distinct pro- and anti-inflammatory bacteria associated with BD have been identified. Methods: To establish disease-associated determinants, we performed gut microbiome profiling in BD patients from the Netherlands (n = 19) and Italy (n = 13), matched healthy controls (HC) from the Netherlands (n = 17) and Italy (n = 15) and oral microbiome profiling in Dutch BD patients (n = 18) and HC (n = 15) by 16S rRNA gene sequencing. In addition, we used fecal IgA-SEQ analysis to identify specific IgA coated bacterial taxa in Dutch BD patients (n = 13) and HC (n = 8). Results: In BD stool samples alpha-diversity was conserved, whereas beta-diversity analysis showed no clustering based on disease, but a significant segregation by country of origin. Yet, a significant decrease of unclassified Barnesiellaceae and Lachnospira genera was associated with BD patients compared to HC. Subdivided by country, the Italian cohort displays a significant decrease of unclassified Barnesiellaceae and Lachnospira genera, in the Dutch cohort this decrease is only a trend. Increased IgA-coating of Bifidobacterium spp., Dorea spp. and Ruminococcus bromii species was found in stool from BD patients. Moreover, oral Dutch BD microbiome displayed increased abundance of Spirochaetaceae and Dethiosulfovibrionaceae families. Conclusions: BD patients show decreased fecal abundance of Barnesiellaceae and Lachnospira and increased oral abundance of Spirochaetaceae and Dethiosulfovibrionaceae. In addition, increased fecal IgA coating of Bifidobacterium, Ruminococcus bromii and Dorea may reflect retention of anti-inflammatory species and neutralization of pathosymbionts in BD, respectively. Additional studies are warranted to relate intestinal microbes with the significance of ethnicity, diet, medication and response with distinct pro- and inflammatory pathways in BD patients.

Adalimumab provides long-lasting clinical improvement in refractory mucocutaneous Behçet's disease without formation of antidrug antibodies.

OBJECTIVES: The TNF-blocker adalimumab can be effective in Behçet's disease (BD), a multisystem auto-inflammatory disorder. Unfortunately, the therapeutic efficacy of TNF-blockers can be hampered by the formation of anti-drug antibodies. We present an observational study of adalimumab in refractory BD with measurement of anti-drug antibodies. METHODS: The effect of fortnightly 40mg adalimumab in nine patients with therapy refractory mucocutaneous, non-ocular or organ threatening BD was studied up to 60 months. Primary endpoint was a decrease in disease activity, measured by the BD Current Activity Form (BDCAF) within 6 months. Secondary endpoints included serum cytokines and the long-term formation of anti-adalimumab antibodies. RESULTS: BDCAF improved significantly in all nine patients from 5.4 (SD=1.4) to 2.4 (SD=1.4) (p=0.007) within one month up to 6 months and after prolonged follow up of 5 years. All patients could either taper or stop concomitant therapy. Symptoms of mucocutaneous lesions, erythema nodosum and joint involvement decreased or disappeared. Serum TNF-alpha levels were elevates in five patients and decreased upon treatment (p=0.017). Adalimumab was save and none of the patients experienced therapy failure or antibodies against adalimumab. CONCLUSIONS: We present an observational study on patients with BD treated with adalimumab and provide a basis for long-term use in refractory mucocutaneous BD. These findings show that adalimumab can safely be administered yielding sustainable clinical effects in refractory BD patients with mucocutaneous disease without formation of anti-adalimumab antibodies, even after long follow up.

Broad IgG repertoire in patients with chronic rhinosinusitis with nasal polyps regulates proinflammatory IgE responses.

BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) is often characterized by local production of polyclonal IgE idiotypes. Although tissue IgE concentrations can be in the range of several thousand kilounits per liter, the regulatory mechanisms by which IgE-mediated inflammation is controlled in patients with nasal polyps are not well understood. OBJECTIVE: We sought to determine whether locally induced IgG antibodies in patients with nasal polyps can inhibit an IgE-mediated proallergic response. METHODS: Nasal polyp homogenates were collected from patients with grass pollen allergy with CRSwNP and nonallergic control subjects. IgE levels were measured using the Immuno Solid-phase Allergen Chip assay. IgE-containing nasal polyp homogenates with or without IgG depletion were evaluated for their capacity to promote IgE-facilitated allergen presentation, basophil activation, and histamine release. Local IgE and IgG repertoires were evaluated using Immunoglobulin 454 sequencing. RESULTS: We show that IgG plays a key role in controlling IgE-mediated inflammatory responses in patients with nasal polyps. Depletion of IgG from nasal homogenates resulted in an increase in CD23-mediated IgE-facilitated allergen binding to B cells but also enhanced FcεRI-mediated allergen-driven basophil activation and histamine release. A similar response was observed in relation to specific IgE antibodies to Staphylococcus aureus enterotoxins. The capacity of IgG in nasal polyps to limit IgE-mediated inflammation is based on the fact that IgG repertoires widely share the antigen targets with the IgE repertoires in both allergic and nonallergic subjects. CONCLUSION: Polyclonal IgE idiotypes in patients with CRSwNP are functional, promote IgE-mediated proallergic inflammation, and are partially antagonized by corresponding IgG idiotypes. This is most likely due to the fact that IgE and IgG clonotypes are widely shared in patients with nasal polyps.

Nasal allergen-neutralizing IgG4 antibodies block IgE-mediated responses: Novel biomarker of subcutaneous grass pollen immunotherapy.

BACKGROUND: Grass pollen subcutaneous immunotherapy (SCIT) is associated with induction of serum IgG4-associated inhibitory antibodies that prevent IgE-facilitated allergen binding to B cells. OBJECTIVE: We sought to determine whether SCIT induces nasal allergen-specific IgG4 antibodies with inhibitory activity that correlates closely with clinical response. METHODS: In a cross-sectional controlled study, nasal fluid and sera were collected during the grass pollen season from 10 SCIT-treated patients, 13 untreated allergic patients (with seasonal allergic rhinitis [SAR]), and 12 nonatopic control subjects. Nasal and serum IgE and IgG4 levels to Phleum pratense components were measured by using the Immuno Solid Allergen Chip microarray. Inhibitory activity was measured by IgE-facilitated allergen binding assay. IL-10+ regulatory B cells were quantified in peripheral blood by using flow cytometry. RESULTS: Nasal and serum Phl p 1- and Phl p 5-specific IgE levels were increased in patients with SAR compared to nonatopic control subjects (all, P < .001) and SCIT-treated patients (nasal, P < .001; serum Phl p 5, P = .073). Nasal IgG4 levels were increased in the SCIT group compared to those in the SAR group (P < .001) during the pollen season compared to out of season. IgG-associated inhibitory activity in nasal fluid and serum was significantly increased in the SCIT group compared to that in the SAR (both, P < .01). The magnitude of the inhibitory activity was 93% (P < .001) in nasal fluid compared to 66% (P < .001) in serum and was reversed after depletion of IgG. Both nasal fluid (r = -0.69, P = .0005) and serum (r = -0.552, P = .0095) blocking activity correlated with global symptom improvement. IL-10+ regulatory B cells were increased in season compared to out of season in the SCIT group (P < .01). CONCLUSION: For the first time, we show that nasal IgG4-associated inhibitory activity correlates closely with the clinical response to allergen immunotherapy in patients with allergic rhinitis with or without asthma.

Update on Biomarkers to Monitor Clinical Efficacy Response During and Post Treatment in Allergen Immunotherapy.

Allergen immunotherapy (AIT) is an immune modulating treatment for allergic diseases. Although highly effective, some patients do not respond to the treatment. To date there are no surrogate biomarkers that are predictive of the clinical response to AIT. More and more is known about the underlying immunological mechanism involved in AIT. Through modulation of both innate and adaptive immune responses, involving reduced ILC2 and enhanced Treg and Breg induction and functionality, along with induction of IgG4 antibody production which have the capacity to inhibit both allergen-induced basophil responsiveness and CD23-mediated IgE-facilitated allergen presentation, the result is an immune skewing towards a more balanced Type I response. So far, however there is not a clear correlation with the observed immunological changes and predictive correlates of clinical efficacy. The most promising biomarker of successful AIT is IgE-FAB as a reflection of functional IgG4. Cellular responses and cytokine analysis gives a great deal of insight into the mechanisms of AIT but may not represent useful or indeed reliable biomarkers in a clinical setting. There is a need for more research for confirmation and interpretation of the possible association with biomarkers and clinical response to AIT.

Applications and mechanisms of immunotherapy in allergic rhinitis and asthma.

Clinical and immunologic tolerance are hallmarks of successful allergen immunotherapy (AIT). Clinical benefits such as reduced symptoms, pharmacotherapy intake and improvement of quality of life persist following cessation of treatment. Successful AIT is associated with suppression of allergic inflammatory cells such as mast cells, eosinophils and basophils in target organs. Furthermore, AIT down-regulates type 2 innate lymphoid cells and allergen-specific type 2 T-helper (Th2) cells. The immunologic tolerant state following AIT is associated with the induction of distinct phenotypes of regulatory T-cells (T-regs) including interleukin (IL)-10-, IL-35- and transforming growth factor (TGF)-ß- producing T-regs and FoxP3+ T-regs. B-cell responses, including the induction of IL-10+ regulatory B-cells (B-regs) and the production of IgG4-associated blocking antibodies are also induced following successful AIT. These events are associated with the suppression of antigen-specific Th2 responses and delayed immune deviation in favour of Th1 type responses. Insight into the mechanisms of AIT has allowed identification of novel biomarkers with potential to predict the clinical response to AIT and also novel therapeutic strategies for more effective and safer AIT.