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

Comparison of clinical research trends and hotspots in allergic rhinitis and asthma from 2013 to 2023 based on bibliometric analysis

Purpose

To analyze and compare clinical research trends and hot topics in allergic rhinitis (AR) and asthma and provide valuable theoretical data and references for future research.

Methods

Clinical studies focusing on AR or asthma published from 2013 to 2023 were retrieved from the Web of Science Core Collection. Eligible articles were screened and analyzed using bibliometrics from multiple indicators.

Results

A total of 261 eligible articles on AR and 991 qualified articles on asthma were screened. The following bibliometric analyses identified the Journal of Allergy and Clinical Immunology as the most influential publication on AR and asthma and proved the significant contributions of Harvard University in clinical studies on AR and asthma. The analyses also revealed that the top ten prolific authors for AR were from China, the United Kingdom, Japan, and Germany, whereas the top ten productive authors for asthma were mainly from the USA. Collaborations among countries for AR were relatively concentrated in the Occident, whereas international cooperation on asthma was mainly achieved by the Occident and certain Eastern countries.

Conclusions

This study compared and analyzed the current status and evolution of AR and asthma-related clinical research using bibliometric analysis. Additionally, the study comprehensively summarized the impactful authors, institutions, and countries, and revealed the replacement and evolution of hotspots.

Evaluation and Comparison of the Efficacy of Subcutaneous and Sublingual Immunotherapy for the Treatment of Allergic Asthma in Children

Specific immunotherapy represents the only potentially curative treatment for allergic asthma. Allergens can be administered subcutaneously (SCIT) or sublingually (SLIT). The aim of the current study was to evaluate and compare the efficacy of SCIT and SLIT for the treatment of allergic asthma in children. Our study included 69 children with allergic asthma who underwent immunotherapy for house dust mites or pollen for at least 3 consecutive years. After 3 years of SCIT and SLIT, the median number of asthma exacerbations in the last three months decreased from 2 to 0 (p < 0.01) and from 1 to 0 (p < 0.01), respectively. When comparing the efficacy of SCIT and SLIT, our study revealed a significantly better efficacy of SCIT only in terms of increasing lung function. The median increase in forced expiratory volume in one second (FEV1) after 3 years was 8% with SCIT and -1% with SLIT (p < 0.01). Daily controller therapy could be withdrawn or reduced in 9 out of 16 (56.3%) children who received it before SCIT (p < 0.01) and in 19 of 29 (65.6%) children who received it before SLIT (p < 0.01), but the difference in efficacy was not significant (p = 0.88). Both SCIT and SLIT are effective treatments for allergic asthma in children.

House dust mite allergen avoidance strategies for the treatment of allergic asthma: A hypothesis-generating meta-analysis

Background

This study continues the review by Gøtzsche and Johansen (Cochrane Database of Systematic Reviews, 2008, Art. No: CD001187), aiming to systematically generate hypotheses on the effectiveness of (sub)strategies for house dust mite allergen avoidance in the treatment of allergic asthma.

Methods

We used the trials previously analysed by Gøtzsche and Johansen and searched recently published studies. Data on asthma symptom scores (ASS), ACQ, number of improved patients, AQLQ-scores, medication use, FEV1%, PC20, and FeNO levels were analysed. The effectiveness of strategies was assessed using Metafor in R.

Results

Thirty-five trials involving 2419 patients were included in the final study. The patient-reported outcome number of patients with improved condition following total bedroom control was RR = 3.39 (95% confidence interval: 1.04 to 11.04, P = 0.04). The mean differences in the ASS by nocturnal air purification was -0.7 (95% confidence interval: -1.08 to -0.32, P < 0.001). Other outcomes including partial bedroom control were non-significant or clinically not of importance.

Conclusions

Total bedroom control and nocturnal air purification of the breathing zone hypothetically provides clinical benefits in patients with house dust mite-induced allergic asthma. The number of patients with improvements in their condition respectively the asthma symptom score differences showed potential in small subgroups, consisting of single studies. Partial bedroom control is not recommended.

Systematic Review Registration

Prospero CRD42022323660.

Preventive allergen immunotherapy with inhalant allergens in children

The efficacy and safety of preventive allergen immunotherapy (pAIT) in children are currently under investigation. Here, we provide an overview of pAIT with respiratory allergens concerning the prevention of new sensitizations, allergic disease onset and progression as well as further immunomodulatory effects. Three databases were searched for clinical pAIT studies in children. Selected publications were reviewed for preventive outcomes according to prevention level (primary, secondary, and tertiary), allergen type, administration route, dose, and treatment duration. The primary prevention approach appears safe but showed no allergen-specific effect on new sensitizations. Secondary prevention seems feasible and may induce regulatory T cell-mediated immunotolerance. The number of studies at these prevention levels is limited. Tertiary prevention with grass and/or tree pollen-based pAIT has shown efficacy in preventing disease progression from allergic rhinitis/conjunctivitis to asthma. Data on tertiary pAIT with house dust mites and other allergen types are inconclusive. Subcutaneous and sublingual routes appear similarly effective, but head-to-head comparative paediatric studies are scarce. Additionally, there are fewer placebo-controlled studies. Nevertheless, immunomodulatory outcomes of pAIT are encouraging. Currently, limited but favourably suggestive evidence is available for preventing respiratory allergic diseases in children by pAIT. Primary and secondary prevention have potential and warrant further investigation through well-designed studies.

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.

Causal relationship between Butyricimonas and allergic asthma: a two-sample Mendelian randomization study

Background

Growing evidence has well documented the close association between the gut microbiome and allergic respiratory disease, which has been notably represented by allergic asthma. However, it is unclear whether this association is a causal link. Therefore, we investigated the potential causal associations between the gut microbiome and allergic asthma or other allergic diseases.

Methods

In this study, we performed two-sample Mendelian randomization (MR) analyses by using the publicly available genome-wide association study (GWAS) summary data. Single-nucleotide polymorphisms (SNPs) that significantly correlated were selected as instrumental variables. The inverse variance weighted (IVW) method was used to examine the potential causal gut microbial genera for allergic asthma and other allergic diseases. The robustness of the primary findings of the MR analyses was ensured by using different sensitivity analyses.

Results

Combining the findings from multiple analyses, the host genetic-driven increases in Butyricimonas at the genus level were positively correlated with the risk of allergic asthma. In addition, phylum Bacteroidetes and class Bacteroidia were also found to have negative associations with the risk of allergic asthma; genus Slackia was identified as having potential causal effects with allergic asthma. No clear evidence of pleiotropy and heterogeneity was observed in genus Butyricimonas. Butyricimonas was also found to have an association with allergic rhinitis, but not with other allergic diseases.

Conclusion

Our findings indicate that there are new gut microbial genera that were causally associated with the risk of allergic asthma and other allergic diseases, and offer novel insights into the pathogenesis of allergic respiratory diseases.