Principles of Allergen Immunotherapy and Its Clinical Application in China: Contrasts and Comparisons with the USA

Safety of subcutaneous immunotherapy with Novo-Helisen-Depot in the children: a retrospective analysis from a single center in Northern China

Background

Little is known about the safety of mite extract product Novo-Helisen Depot (NHD) as subcutaneous immunotherapy (SCIT) in the children with mite allergy especially immediate/late local reaction (LRs).

Methods

We conducted a retrospective study analyzing the adverse events of the children undergoing subcutaneous immunotherapy with NHD. Adverse events included local and systemic adverse reactions (SRs) at the very early and late stage. The correlation of the basic characteristics, laboratory analysis results, LRs and SRs were analyzed.

Results

Two hundred and eighty-seven patients received at least 15 months of subcutaneous immunotherapy with NHD were included in the analysis. Skin-prick testing (SPT) results of D. pteronyssinus was associated with an increased risk of immediate LRs in build-up phase (OR = 1.53, 95% CI: 1.02, 2.37) and delayed LRs in maintenance phase (OR = 1.58, 95% CI: 1.05, 2.46), while SPT results of D. farinae was associated with an increased risk of SRs (OR = 3.22, 95% CI: 1.17, 10.00) and severe SRs (OR = 7.68, 95% CI: 1.13, 109.50). Serum IgE level of D. pteronyssinus was associated with an increased risk of SRs (OR = 1.01, 95% CI: 1.00, 1.03). Patients with both asthma and allergic rhinitis was associated with an increased risk of SR, and severe SRs (P < 0.05).

Conclusion

NHD as SCIT is safe. The children with higher SPT level with D. farinae or D. pteronyssinus, higher serum IgE level of D. pteronyssinus, children with both asthma and allergic rhinitis, and the children with treatment interruption had higher risk of adverse events.

Allergen immunotherapy in China

Allergen immunotherapy (AIT) is an etiological treatment strategy that involves administering escalating doses of clinically relevant allergens to desensitize the immune system. It has shown encouraging results in reducing allergy symptoms and enhancing patients' quality of life. In this review, we offer a thorough overview of AIT in China, examining its efficacy, safety, current practices, and prospects. We further underscore the progress made in AIT research and clinical applications, as well as the distinct challenges and opportunities that China faces in this area.

Nasal delivery of an immunotherapeutic vaccine in thermosensitive hydrogel against allergic asthma

Asthma poses a significant threat to public health, with an estimated burden of over 334 million people worldwide. Available treatments are often inadequate. We developed a thermo-sensitive hydrogel vaccine containing allergen and FK506 that induced immune tolerance via intranasal administration to treat experimental allergic asthma. The hydrogel delivery system was formulated based on Poloxamer 407 (P407), Carbopol 974P NF, and Polyoxyl 15 hydroxystearate (Kolliphor HS15, HS15). It flowed freely at room temperature and rapidly formed a hydrogel in the nasal cavity once the temperature rose over 33 °C. Ovalbumin and FK506 were slowly released from the hydrogel form and their mucosal residence time was significantly prolonged compared to the liquid formulation. In both an OVA-induced asthma model and an HDM-induced asthma model, the vaccines formulated in hydrogel gave lower levels of eosinophilic inflammation, and airway remodeling. The reduction of lung function was ameliorated, and Foxp3-expressing CD4 + Treg cells were significantly higher. The frequency of Foxp3 + Tregs in lung-draining lymph nodes (dLNs) was correlated with the amelioration. Depletion of Foxp3 + Treg cells abolished the beneficial effects of the allergen/FK506 hydrogel vaccinations. Thus, the allergen/FK506 hydrogel formulation has the potential to be a delivery system for therapeutic allergy vaccines to induce immune tolerance.

Identification and characterization of natural PR-1 protein as major allergen from Humulus japonicus pollen

BACKGROUND

The Humulus japonicus pollen is one of the most common allergenic pollens in China. However, little is unveiled regarding the allergenic components in Humulus japonicus pollen. Our study aimed to purify and identify the pathogenesis-related 1 (PR-1) protein from Humulus japonicus pollen, and to characterize the molecular and immunochemical properties of this novel allergen.

METHODS

The natural PR-1 protein (named as Hum j PR-1) was purified from Humulus japonicus pollen extracts with a combined strategy of chromatography, and identified by mass spectrometry. The coding sequence of Hum j PR-1 was confirmed by cDNA cloning. The recombinant Hum j PR-1 was expressed and purified from Escherichia coli. The allergenicity was assessed by immunoblot, enzyme-linked immunosorbent assay (ELISA), inhibition ELISA, and basophil activation test using Humulus japonicus allergic patients' whole blood. The physicochemical properties and 3-dimensional structure of it were comprehensively characterized by in silico methods.

RESULTS

The allergenicity analysis revealed that 76.6 % (23/30) of the Humulus japonicus pollen allergic patients displayed specific IgE recognition of the natural Hum j PR-1. The cDNA sequence of Hum j PR-1 had a 516-bp open reading frame encoding 171 amino acids. Physicochemical analysis indicated that Hum j PR-1 was a stable and relatively thermostable protein. Hum j PR-1 shared a similar 3-dimensional folding pattern with other homologous allergens, which was a unique αβα sandwich structure containing 4 α-helices and 6 antiparallel β-sheets, encompassing 4 conserved CAP domain.

CONCLUSION

The natural PR-1 was firstly purified and characterized as a major allergenic allergen in Humulus japonicus pollen. These findings would contribute to developing diagnostic and therapeutic strategies for Humulus japonicus pollinosis.

Emerging Hop Japanese Pollinosis in Asia

Hop Japanese (Hop J) pollen has been considered one of the major causative pollen allergens in Far East Asia in the autumn season. The sensitization rate, pollen count, and allergenicity of Hop J pollens are increasing in this region because of increased air pollution and global warming. However, commercial skin test agents for the diagnosis and allergen extracts for the allergen immunotherapy are not available. This review summarizes recent data on clinical impact of Hop J pollinosis in order to facilitate the development of diagnostic and therapeutic agents for this region.

Chinese Guideline on Allergen Immunotherapy for Allergic Rhinitis: The 2022 Update

In the last few decades, there has been a progressive increase in the prevalence of allergic rhinitis (AR) in China, where it now affects approximately 250 million people. AR prevention and treatment include allergen avoidance, pharmacotherapy, allergen immunotherapy (AIT), and patient education, among which AIT is the only curative intervention. AIT targets the disease etiology and may potentially modify the immune system as well as induce allergen-specific immune tolerance in patients with AR. In 2017, a team of experts from the Chinese Society of Allergy (CSA) and the Chinese Allergic Rhinitis Collaborative Research Group (C2AR2G) produced the first English version of Chinese AIT guidelines for AR. Since then, there has been considerable progress in basic research of and clinical practice for AIT, especially regarding the role of follicular regulatory T (TFR) cells in the pathogenesis of AR and the use of allergen-specific immunoglobulin E (sIgE) in nasal secretions for the diagnosis of AR. Additionally, potential biomarkers, including TFR cells, sIgG4, and sIgE, have been used to monitor the incidence and progression of AR. Moreover, there has been a novel understanding of AIT during the coronavirus disease 2019 pandemic. Hence, there was an urgent need to update the AIT guideline for AR by a team of experts from CSA and C2AR2G. This document aims to serve as professional reference material on AIT for AR treatment in China, thus improving the development of AIT across the world.

Application of Different Ventilation Modes Combined with AutoFlow Technology in Thoracic Surgery

To investigate the effect of AutoFlow on airway pressure and hemodynamics in mechanical ventilation constant volume-control ventilation mode, 100 patients receiving mechanical ventilation were randomly divided into observation group (SIMV-PSV-PEEP + AutoFlow) and control group (SIMV-PSV-PEEP). The results showed that the peak airway pressure and average airway pressure decreased with different flow rate settings and automatic flow conversion (P < 0.05). The peak airway pressure and mean airway pressure decreased with different resistance settings (P < 0.05). With different compliance settings, the peak airway pressure and average airway pressure decreased after being assisted with an automatic converter (P < 0.05). Adding AutoFlow on the basis of SIMV-PSV mode can significantly reduce peak inspiratory pressure (PIP), mean airway pressure (Pmean), and airway resistance (R). There was no significant difference in hemodynamic monitoring results between the observation group and the control group. It is proved that the SIMV constant volume-controlled ventilation mode combined with AutoFlow can not only ensure tidal volume but also avoid excessive airway pressure, which has little effect on hemodynamics.

Prevalence of Sensitization to Aeroallergens in Greater Beijing Region Children With Respiratory Allergy

OBJECTIVE

To evaluate the prevalence and distribution of sensitization to aeroallergens in children with atopic diseases.

METHODS

We conducted skin prick test on 9,527 pediatric patients (aged 0-17 years) with atopic diseases in allergy department of Children's Hospital affiliated with the Capital Institute of Pediatrics. Positive rates of aeroallergens were compared among the different groups.

RESULTS

Boys (69.5%) had a higher positive rate in SPT results than girls (59.8%; χ² = 91.7, P < 0.01), and the prevalence of sensitization to aeroallergens increased from 56.1% in the 0-5 year group, to 73.0% in patients above 12 years. Japanese hop (36.2%) and D. farinae (28.1%) were the most common outdoor and indoor aeroallergens, respectively. From low to high age groups, the positive detection rates of D. farinae were 20.3, 30.6, and 33.5%, respectively, followed by D. pteronyssinus (15.7, 24.8, and 30.0%) and cat dander (8.6, 19.8, and 27.9%, respectively), while dog dander and cockroach showed the same trend. The top three positive detection rates of outdoor aeroallergens were Alternaria (30.9%), Japanese Hop (26.7%), and Artemisia (23.7%) in the preschool age group. With regard to patients aged 6 to 11 years, the three most common were Japanese hop (39.2%), Alternaria (36.4%), and Fraxinus pollen (34.4%). Japanese hop (43.8%), Sabina (41.1%), and birch pollen (39.6%) became increasingly common allergens among adolescents. There were more patients with strongly positive reactions to Alternaria in AS (χ² = 10.2, P < 0.01) and AS with AR groups (χ² =9.7, P < 0.01) than those in the AR group. Asthmatic patients had significantly higher multiple positive reactions than those with AR (P < 0.01). Asthmatic patients had a much higher prevalence of HDM, animal dander, and Alternaria than those with allergic rhinitis (P < 0.05).

CONCLUSION

The prevalence of sensitization to aeroallergens increased with age in children with atopic diseases in Greater Beijing Region. Alternaria was the predominant allergen before 5 years of age, and tree pollen had delayed sensitization in adolescents. Sensitization to perennial allergens such as HDM, cats, and Alternaria was more strongly associated with asthma risk. Sensitization to more than one allergen significantly affected asthmatic patients.

Alternaria as an Inducer of Allergic Sensitization

Alternaria alternata is a saprophytic mold whose spores are disseminated in warm dry air, the typical weather of the Mediterranean climate region (from 30° to 45°), with a peak during the late summer and early autumn. Alternaria spores are known to be biological contaminants and a potent source of aeroallergens. One consequence of human exposure to Alternaria is an increased risk of developing asthma, with Alt a 1 as its main elicitor and a marker of primary sensitization. Although the action mechanism needs further investigation, a key role of the epithelium in cytokine production, TLR-activated alveolar macrophages and innate lymphoid cells in the adaptive response was demonstrated. Furthermore, sensitization to A. alternata seems to be a trigger for the development of co-sensitization to other allergen sources and may act as an exacerbator of symptoms and an elicitor of food allergies. The prevalence of A. alternata allergy is increasing and has led to expanding research on the role of this fungal species in the induction of IgE-mediated respiratory diseases. Indeed, recent research has allowed new perspectives to be considered in the assessment of exposure and diagnosis of fungi-induced allergies, although more studies are needed for the standardization of immunotherapy formulations.

Prevalence of and risk factors for asthma among people aged 45 and older in China: a cross-sectional study

Background

Asthma is one of the most prevalent chronic respiratory diseases worldwide. This study aimed to determine the updated prevalence of and risk factors for asthma among individuals aged 45 and older in mainland China.

Methods

The data for this study came from the fourth wave of the China Health and Retirement Longitudinal Study (CHARLS) conducted by the National School of Development of Peking University in 2018. The CHARLS is a nationally representative survey targeting populations aged 45 and over from 28 provinces/cities in mainland China. A representative sample of 19,816 participants was recruited for the study using a multistage stratified sampling method. The prevalence of asthma was determined across different characteristics. The potential risk factors were examined by multivariable logistic regressions.

Results

A total of 18,395 participants (8744 men and 9651 women) were eligible for the final data analysis. The estimated prevalence of asthma among Chinese people aged ≥ 45 years in 2018 was 2.16% (95% CI 1.96–2.38). The prevalence of asthma significantly differed according to race (P = 0.002), with an overall rate of 2.07% (95% CI 1.86–2.29) in Han paticipants and 3.32% (95% CI 2.50–4.38) in minority participants. Furthermore, the minority ethnicities (OR = 1.55 [95% CI 1.12–2.14], P = 0.008), older age (60–69 years group: OR = 1.85 [95% CI 1.17–2.92], P = 0.008; ≥ 70 years group: OR = 2.63 [95% CI 1.66–4.17], P < 0.001), an education level of middle school or below (middle-school education: OR = 1.88 [95% CI 1.15–3.05], P = 0.011; primary education: OR = 2.48 [95% CI 1.55–3.98], P < 0.001; literate: OR = 2.53 [95% Cl 1.57–4.07], P < 0.001; illiterate: OR = 2.78 [95% CI 1.72–4.49, P < 0.001]), smoking (OR = 1.37 [95% CI 1.11–1.68], P = 0.003), and residence in North (OR = 1.52 [95% CI 1.11–2.09], P = 0.01) or Northwest China (OR = 1.71 [95% CI 1.18–2.49], P = 0.005) were associated with prevalent asthma.

Conclusions

Asthma is prevalent but underappreciated among middle-aged and elderly people in China. A number of risk factors were identified. These results can help to formulate correct prevention and treatment measures for asthma patients.

Characterization of allergenicity of Platanus pollen allergen a 3 (Pla a 3) after exposure to NO2 and O3

Pollen allergens, widely present in the atmosphere, are the main cause of seasonal respiratory diseases that affect millions of people worldwide. Although previous studies have reported that nitrogen dioxide (NO₂) and ozone (O₃) promote pollen allergy, the specific biological processes and underlying mechanisms remain less understood. In this study, Platanus pollen grains were exposed to gaseous pollutants (NO₂ and O₃). We employed environmental electron microscopy, flow cytometry, western blot assay, enzyme-linked immunoassay, ultraviolet absorption spectrometry, circular dichroism, and protein mass spectrometry to characterise the subpollen particles (SPPs) released from pollen grains. Furthermore, we determined the immunogenicity and pathogenicity induced by Platanus pollen allergen a 3 (Pla a 3). Our results demonstrated that NO₂ and O₃ could damage the pollen cell membranes in SPPs and increase the amount of Pla a 3 allergen released into the atmosphere. Additionally, NO₂ and O₃ altered the structure of Pla a3 protein through nitrification and oxidation, which not only enhanced the immunogenicity of allergens but also increased the stability of the protein. In vivo analysis using an animal model indicated that NO₂ and O₃ greatly aggravated pollen-induced pneumonia. Thus, our study provides guidance for the prevention of pollen allergic diseases.