Trends of Sensitization to Inhalant Allergens in Korean Children Over the Last 10 Years

KAAACI Guidelines for Allergen Immunotherapy

Allergen immunotherapy (AIT) is a causative treatment for various allergic diseases such as allergic rhinitis, allergic asthma, and bee venom allergy that induces tolerance to offending allergens. The need for uniform practice guidelines in AIT is continuously growing because of the increasing discovery of potential candidates for AIT and evolving interest in new therapeutic approaches. This guideline is an updated version of the Korean Academy of Asthma Allergy and Clinical Immunology recommendations for AIT published in 2010. This updated guideline proposes an expert opinion by allergy, pediatrics, and otorhinolaryngology specialists with an extensive literature review. The guideline deals with basic knowledge and methodological aspects of AIT, including mechanisms, clinical efficacy, patient selection, allergens extract selection, schedule and doses, management of adverse reactions, efficacy measurements, and special consideration in pediatrics. The guidelines for sublingual immunotherapy will be covered in detail in a separate article.

Annual Change in Fungal Concentrations and Allergic Sensitization Rates to Alternaria and Cladosporium in Korea During the Period 1998-2022

PURPOSE

Atmospheric fungi are associated with respiratory allergies in humans, and some fungal spores can cause allergic diseases. Environmental and biological factors influence the concentrations of atmospheric spores. In this study, we evaluated the climate change-induced annual variations in fungal spore concentrations and allergic sensitization rates in the Seoul Metropolitan Area over a period of 25 years.

METHODS

Fungal spores and pollen were obtained from Hanyang University Seoul and Guri Hospitals; they were identified and counted for 25 years (1998-2022). The study participants included patients who underwent tests for allergic diseases in both hospitals. Their allergenic sensitization rates were determined via allergic skin prick and serum tests, after which their sensitization rates to allergenic fungi and pollens were calculated. The daily climatic variables were obtained from the Korea Meteorological Administration.

RESULTS

The total annual atmospheric fungal concentrations decreased in both areas during the period. Simultaneously, we recruited 21,394 patients with allergies (asthma, 1,550; allergic rhinitis, 5,983; and atopic dermatitis, 5,422) from Seoul and Guri Hospitals for allergenic fungal sensitization evaluations over the period. The allergenic fungal sensitization rates decreased annually in both areas over that time `+(Alternaria [3.5%] and Cladosporium [4.4%] in 1998; Alternaria [0.2%] and Cladosporium [0.2%] in 2022). In contrast, the annual pollen concentrations increased with the sensitization rates to pollen in children.

CONCLUSIONS

The atmospheric fungal concentrations decreased annually, with allergic sensitization rate decreasing over the period of 25 years. Allergenic fungal sporulation could decrease with climate changes, such as desertification and drought. Extended monitoring periods and further large-scale studies are required to confirm the causality and to evaluate the impact of climate change.

Investigating the microbiome of house dust mites in South Korea

Understanding the house dust mites (HDMs) microbiome is crucial due to its potential effects on the development of allergic diseases. In 1998, our laboratory collected Dermatophagoides farinae and D. pteronyssinus from beds in a Korean household and began cultivating these HDMs. Our laboratory has been actively investigating several topics about HDMs in recent years, including the bacterial and fungal microbiome and their interactions, as well as the impact of the HDM microbiome on airway inflammation. To study the D. farinae microbiome, we employed high-throughput sequencing of the 16S rDNA amplicons. The results revealed that the two most abundant bacteria were Enterococcus faecalis and Bartonella spp. In contrast, we found almost no bacteria in D. pteronyssinus. By inoculating bacteria to HDMs, we found that D. farinae is more susceptible to bacteria than D. pteronyssinus. This susceptibility was associated with the presence of certain fungal species in D. pteronyssinus. Additionally, we have recently made efforts to produce HDMs with reduced levels of symbiotic bacteria. We believe that standardizing and controlling the microbiome in HDMs are crucial steps for the future development and improvement of allergic immunotherapies.

Allergic Sensitization Pattern in the Korean Dermatologic Patients

BACKGROUND

Avoiding causative allergens is important for controlling the clinical course of allergic diseases. Allergen sensitization is influenced by many factors including the environment and lifestyle. The socioeconomic development, climate, and lifestyle changes have increased the prevalence of allergic diseases worldwide. However, there is little information about changes in the trend of the common allergens over time.

OBJECTIVE

This study was aimed at identifying the trends of the common allergens in Korea over a 10-year period based on the results of the multiple allergosorbent test chemiluminescent assay (MAST-CLA).

METHODS

We retrospectively reviewed the medical records of 5,760 patients aged ≥18 years who visited the Dermatology Department at a tertiary hospital over a period of 10 years. The serum total immunoglobulin (Ig) E and specific IgE levels to 41 allergens were determined using MAST-CLA, along with the clinical diagnosis, duration of illness, white blood cell count and eosinophil percentage.

RESULTS

Dermatophagoides farinae, Dermatophagoides pteronyssinus, and house dust were the most prevalent allergens during the 10 years period, but the percentage of higher class responses has decreased in recent years. The number of patients sensitized to house dust (p<0.001), dogs (p=0.005), and cats (p<0.001) increased while that of patients sensitized to cockroaches (p<0.001) and storage mites (p<0.001) decreased over time. There were no significant changes in the total number of sensitizing allergens over time.

CONCLUSION

The common allergens have changed over time. Based on the findings of this study, physicians and patients should consider changing their strategies for disease prevention and management.

Allergies to food and airborne allergens in children and adolescents: role of epigenetics in a changing environment

Allergic diseases affect millions of children and adolescents worldwide. In this Review, we focus on allergies to food and airborne allergens and provide examples of prevalence trends during a time when climate change is of increasing concern. Profound environmental changes have affected natural systems in terms of biodiversity loss, air pollution, and climate. We discuss the potential links between these changes and allergic diseases in children, and the clinical implications. Several exposures of relevance for allergic disease also correlate with epigenetic changes such as DNA methylation. We propose that epigenetics could be a promising tool by which exposures and hazards related to a changing environment can be captured. Epigenetics might also provide promising biomarkers and help to elucidate the mechanisms related to allergic disease initiation and progress.

Effects of mechanical washing and drying on the removal of pet allergens

Background: In Korea, the number of households with indoor pets is rapidly increasing in parallel with changes in cultural lifestyles. The sensitization rate of pet allergens is also increasing in Korea. Objective: We evaluated the effectiveness of washing machines to remove dog and cat hair and their allergens. In addition, this study aimed to investigate whether only a mechanical dryer without mechanical washing could be used for pet allergen removal. Method: We brushed cats and dogs, and thereafter collected their hair and used a residential vacuum cleaner to obtain dust and other particulate matter from a household. The contents of the vacuum bag were sifted through a 300-μm sieve filter. Some of the contents were placed in phosphate-buffered saline solution with 0.5% Tween 20 to make a liquid extract. Hair, dust, and liquid extract-contaminated fabric samples after mechanical washing or after drying without mechanical washing were analyzed for pet allergens (Fel d l [cat], Can f 1 [dog]) by using a two-site enzyme-linked immunosorbent assay. We assessed the remaining allergens in the contaminated fabrics after mechanical drying and washing. Results: The mean Fel d l and mean Can f 1 removal ratios after mechanical washing with detergent were > 99.99% for the dust, hair, and liquid extract. The removal ratios after mechanical washing without a detergent were lower for both Fel d 1 and Can f 1, for hair, dust, and their respective liquid extracts (p < 0.05). Mechanical drying was just as effective as mechanical washing with detergent for removing Can f 1 but was less effective for Fel d 1 (p < 0.05). Conclusion: Mechanical washing with detergent is important to remove pet allergens from contaminated fabrics. If washing is difficult, then using just a dryer without washing can be an alternative method to remove allergens from contaminated bedding or clothing.

Environmental and sensitization variations among asthma and/or rhinitis patients between 2008 and 2018 in China

Background

Little is known about the changes in allergen sensitization in China secondary to the environmental variations over the past decade. We aimed at investigating the variations in sensitization among asthma and/or rhinitis patients in China between 2008 and 2018.

Methods

This study analyzed cross‐sectional data from national surveys conducted in China in 2008 and 2018. After finishing the questionnaire, participants underwent serum specific IgE measurements. A total of 2322 and 2798 patients were enrolled in 2008 and 2018, respectively. The significance of differences in sensitization rates among four regions of China were assessed. Correlation analysis was used to identify the associations of sensitization with climate change and planting of Artemisia desertorum between the two surveys.

Results

Compared with 2008, the general sensitization rate to mites significantly increased in 2018, which ranked highest among all tested allergens. Sensitization to pollens, especially Artemisia vulgaris, showed the greatest increase in the north. The annual mean temperature, rainfall and relative humidity in all four regions, and the Artemisia desertorum coverage in the northeastern area, increased significantly in 2018 as compared with 2008. From 2008 to 2018, an increase in Dermatophagoides pteronyssinus sensitization was significantly associated with an increase in relative humidity (r = 0.54, p = 0.037). The increase in A. vulgaris sensitization was significantly associated with the increase in the A. desertorum planting area (r = 0.67, p = 0.006) and with a decrease in rainfall (r = −0.59, p = 0.021).

Conclusions

House dust mites remain the most important allergen in Chinese individuals with asthma and/or rhinitis. Pollen sensitization dramatically increased in northern China. Increases in sensitization to dust mites and Artemisia were related to the increases in humidity and planting area of A. desertorum.

[Sensitization pattern of cat and dog dander allergen in 16 426 patients with allergic diseases]

Objective:To explore the sensitization feature of cat and dog dander and time trend in northern region. Methods:During year 2017 to year 2019, subjects with self-reported allergic diseases received skin prick test for cat and dog dander allergen. Skin index（SI） ≥2+ was considered as positive SPT. SI2+ was defined as mild sensitization, SI3+ was defined as moderate sensitization while SI4+ was defined as severe sensitization. The age and gender difference of sensitization rate between cat and dog dander allergen was analyzed. Meanwhile, the trend of cat and dog dander sensitization rate was analyzed. Results:Overall, 16 426 subjects were enrolled in this study. ① The sensitization rate of cat dander was significantly higher than dog dander（11.8% vs 6.0%, P<0.001）. Severe sensitization rate of cat dander was significantly higher than dog dander（5.9% vs 1.7%, P<0.001） while there was no significant difference of mild sensitization rate. ②Sensitization age of cat dander was younger than dog dander（P<0.001）. Sensitization rate of cat and dog dander was higher in subjects ≤18y compared with those >18y（20.2% vs 10.9%, P<0.001; 8.1% vs 5.7%, P<0, 001）. The highest sensitization rate was presented in 13-18y age group（27.3% vs 9.9%, P<0.001）, following by 7-12y age group（26.0% vs 9.2%, P<0.001）. Sensitization rate of cat dander was higher in male than in female（13.7% vs 10.7%, P<0.001） while no gender difference was observed in dog dander sensitization（6.2% vs 5.8%, P=0.411）. ③595 subjects（3.6%） were both sensitized to cat and dog dander while 1733 subjects（10.6%） were sensitized either to cat or dog dander. Single sensitization rate of cat dander was higher than single sensitization rate of dog dander（8.2% vs 2.3%, P<0.001）. There was a positive correlation between the cat and dog dander sensitization rate（r=0.386, P<0.001）. ④During 2017-2019, the sensitization rate of cat dander increased but without significantly statistic difference while dog dander sensitization rate was descending from 7.4% to 4.6% significantly（χ²=38.298, P<0.001）. Conclusion:Cat dander sensitization rate was higher than dog dander with a peak age in adolescence. A trend of rising for cat dander allergy and descending for dog dander allergy was observed during the past three years.