Patterns of Inhalant Allergen Sensitization and Geographical Variation in Korean Adults: A Multicenter Retrospective Study

PURPOSE: Inhalant allergen sensitization is one of the major factors involved in the pathogenesis of allergic respiratory diseases. However, the sensitization is determined by interactions between genetic and environmental factors. Thus, testing panels of inhalant allergens may differ among geographical areas. Here we aimed to determine 10 common inhalant allergens in Korean adult patients with suspected respiratory allergies and to examine the variation between different geographical locations. METHODS: A total of 28,954 patient records were retrieved for retrospective analysis, from 12 referral allergy clinics located in 9 different areas. Inclusion criteria were Korean adults (≥18 years old) who underwent the inhalant allergen skin prick test for suspected history of respiratory allergy. The primary outcome was inhalant allergen skin prick response. Demographic and clinical information were also collected. Positive skin prick responses to allergens were defined as allergen-to-histamine wheal ratio ≥1. Based on skin test results, the most prevalent aeroallergens were determined. RESULTS: The overall prevalence of allergic sensitization was 45.3%. Dermatophagoides farinae and Dermatophagoides pteronyssinus were the most commonly sensitized allergens. Other common inhalant allergens were cat epithelium (8.1%), birch (7.7%), mugwort (6.9%), alder (6.7%), hazel (6.7%), beech (6.7%), oak (6.6%), and Tyrophagus putres (6.2%), in decreasing order frequency. These 10 inhalant allergens explained 90% of inhalant allergen sensitization in the study participants. However, distinct patterns of the 10 inhalant sensitization were observed in patients living in Chungnam and Jeju. American cockroach, Gernam cockroach, and Trichophyton metagrophytes were unique in Chungnam. Orchard, Japanese cedar, and Velvet were unique in Jeju. CONCLUSIONS: The present analysis suggests a panel of 10 most common inhalant allergens in Korean adult patients with suspected respiratory allergies, which explained 90% of inhalant allergen sensitization. This panel can be utilized as a practical and convenient tool for primary practice and epidemiological surveys of respiratory allergic diseases.

Seasonal Variation in Skin Sensitivity to Aeroallergens

PURPOSE: We previously demonstrated seasonal variation in sensitization to aeroallergens in a small group of patients with exercise-induced asthma. This study was performed to confirm the relationship in a much larger population. METHODS: The charts of 1,891 patients who received allergy skin prick tests were reviewed retrospectively. The test results from subjects aged < or =60 years were compared between the groups classified according to the season when the patients received the tests (spring: March-May, summer: June-August, fall: September-November, winter: December-February). The data from 25 respiratory allergy patients who received the tests two or more times and showed a positive response at least once were analyzed longitudinally. RESULTS: The most prevalent among 29 tested aeroallergens were house dust mites (HDMs) Dermatophagoides pteronyssinus and D. farinae. The skin sensitization rates to D. pteronyssinus (23.2% vs. 32.1%, P=0.004) and D. farinae (22.2% vs. 30.2%, P=0.009) were significantly lower in the summer and higher in the fall (38.3% vs. 26.6% and 35.6% vs. 25.3%; P=0.001 respectively) than those in other seasons in patients with a respiratory allergy (n=1,102). The sensitization rates to weed pollens in the fall (13.9% vs. 8.3%, P=0.006) and to Aspergillus fumigatus in the winter (2.9% vs. 0.7%, P=0.005) were significantly higher. In patients with non-respiratory allergy such as urticaria/anaphylaxis (n=340), the D. farinae sensitization rate was significantly lower in the summer also but higher in the spring. The trend of the HDM sensitization rate being lower in the summer and higher in the fall was observed in the longitudinal study. CONCLUSIONS: Skin sensitivity to aeroallergens such as HDMs, pollens, and molds demonstrates seasonal variation in respiratory allergy patients. Non-respiratory allergy patients also showed seasonal variation in sensitivity to aeroallergens, which might be related to the "priming" effect of allergens.

Seasonal Factors Influencing Exercise-Induced Asthma

PURPOSE: Exercise-induced bronchoconstriction (EIB) in patients with asthma occurs more frequently in winter than in summer. The concentration of house dust mite (HDM) allergens in beds also shows seasonal variation. This study examined the relationship between seasonal differences in the prevalence of EIB and sensitization to HDMs in patients with asthma. METHODS: The medical records of 74 young adult male patients with asthma-like symptoms who underwent bronchial challenge with methacholine, 4.5% saline and exercise, and allergen skin prick tests, were reviewed. The subjects were divided into summer (n=27), spring/fall (n=26) and winter (n=21) groups according to the season during which they underwent testing. RESULTS: The positive responses to exercise differed according to season (48.1% in summer, 73.1% in spring/fall, and 90.5% in winter; P0.05). CONCLUSIONS: Positive skin test reactions to HDMs and EIB occurred in winter, spring/fall, and summer in decreasing order of frequency. Seasonal variation in the prevalence of EIB may be related to seasonal variation in sensitization to HDMs, accompanied by differences in indirect, but not direct, AHR.

Effects of dehydroepiandrosterone on Th2 cytokine production in peripheral blood mononuclear cells from asthmatics

BACKGROUND/AIMS: The androgen dehydroepiandrosterone (DHEA) attenuates allergic inflammatory airway reactions by down-regulating the Th2 response in mice. The purpose of this study was to investigate whether DHEA suppresses Th2 cytokine production in cultured peripheral blood mononuclear cells (PBMCs) from asthmatic patients. METHODS: Sixty-one consecutive suspected asthmatic or non-asthmatic men underwent tests for asthma. PBMCs from each subject were cultured with and without DHEA (0.01~10 micrometer) for 48 h. The concentrations of interferon (IFN)-gamma, interleukin (IL)-5, and IL-10 in the culture supernatant were measured via an enzyme-linked immunosorbent assay. RESULTS: In PBMCs from subjects exhibiting methacholine airway hyperresponsiveness (AHR), DHEA significantly suppressed IL-10, IL-5, and IFN-gamma production in a dose-dependent manner (all p<0.001) and tended to increase the IFN-gamma/IL-5 ratio (p=0.087). DHEA (10 micrometer) suppressed cytokine production to a greater degree in subjects with AHR compared with those without AHR (IL-5: 24.0+/-7.8% vs. 40.9+/-3.6%, p<0.01; IFN-gamma: 29.7+/-7.0% vs. 54.5+/-5.1%, p<0.01). Cytokine suppression was significantly related to AHR, serum total IgE levels, and skin reactivity to house dust mites. CONCLUSIONS: DHEA suppressed both Th1 and Th2 responses, with a Th1 bias, and the degree of suppression was associated with the severity of AHR or atopy. Therefore, DHEA may be a useful therapy for asthma.

Sensitization rates for inhalant allergens in Korea; a multi-center study / 천식및알레르기

BACKGROUND AND OBJECTIVE: There are many differences in common inhalant allergens between countries and regions. We need to determine the major inhalant allergens in this country with geographical characteristics. To observe the major inhalant allergens and establish essential ones for the skin prick test in Korea, a nation-wide multicenter study was performed. METHOD: The skin prick tests were performed with the same kits of 43 allergens on 2,554 allergy patients who visited their regional hospitals for one year. RESULT: There are significant differences in the sensitization rate to common inhalant allergens among the centers. Twenty three allergens showed > or=5% sensitization rate: D. pteronyssinus, D. farinae, Tyrophagus putrescentiae, Tetranychus urticae, Panonychus citri, Alternaria alternata, Cladosporium tenuis, cat fur, dog hair, American and German cockroach, tree pollen mixture I, alder, hazel, tree pollen mixture II, birch, beech, oak, plane tree, ragweed, mugwort, hop Japanese and chrysanthemum. CONCLUSION: We suggest the major allergens such as D. pteronyssinus, D. farinae, T. putrescentiae, T. urticae, P. citri, outdoor molds, indoor molds, cat fur, dog hair, German and American cockroaches, tree pollens, mugwort, and hop Japanese pollen should be included in skin test battery in Korea.