Pre-asthma: a useful concept for prevention and disease-modification? A EUFOREA paper. Part 1-allergic asthma

Asthma, which affects some 300 million people worldwide and caused 455,000 deaths in 2019, is a significant burden to suffers and to society. It is the most common chronic disease in children and represents one of the major causes for years lived with disability. Significant efforts are made by organizations such as WHO in improving the diagnosis, treatment and monitoring of asthma. However asthma prevention has been less studied. Currently there is a concept of pre- diabetes which allows a reduction in full blown diabetes if diet and exercise are undertaken. Similar predictive states are found in Alzheimer's and Parkinson's diseases. In this paper we explore the possibilities for asthma prevention, both at population level and also investigate the possibility of defining a state of pre-asthma, in which intensive treatment could reduce progression to asthma. Since asthma is a heterogeneous condition, this paper is concerned with allergic asthma. A subsequent one will deal with late onset eosinophilic asthma.

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, β (regression coefficient) = 0.04; 95% Confidence Interval [0.02; 0.06]; p < 0.001; and AQLQ; β = -0.04 CI [-0.07; -0.009]; p = 0.013). Conclusion: These results emphasize the importance of bariatric surgery in treating obesity-related asthma.

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.