Background: The aims of this study were to investigate the prevalence of allergic rhinitis (AR) and the accuracy of the International Study of Asthma and Allergies in Childhood (ISAAC) questions for diagnosis of AR, in Korean children. Methods: Students that participated in an allergic disease prevalence survey in 2010–2017 were evaluated (n = 18,425) using questionnaires and a skin prick test (SPT). Age−stratified (5−7, 8−10, 11−13, 14−16 years) prevalence of four rhinitis questions, accuracy of the questions for AR, and proportion of comorbidities in the AR and non-AR (NAR) groups were evaluated. Results: The proportion of students responding to the questionnaire that ever had symptoms of AR since birth, that is, the prevalence of “symptom, ever” was 47.6%. Based on the questionnaire and SPT, overall prevalence of AR and NAR were 21% and 26.5%, respectively. The sensitivity, specificity, and accuracy of “symptom, ever” were 57.5%, 58.4%, and 58.1%, respectively, and those of “diagnosis, ever”, who had ever been diagnosed with AR, were 39.8%, 76.9%, and 63.4%, respectively. Questionnaire−based asthma, atopic dermatitis, and food allergy were significantly associated with the AR group compared to the NAR group. Conclusions: Since the AR accuracy of the questionnaire is about 60%, it should be considered that the questionnaire based survey overestimates the true prevalence of AR in Korean children.

Purpose Bacterial extracellular vesicles (EVs) play crucial roles in bacteria-host interactions. Due to their cargo, EVs are considered fingerprints of the parent cell, which are detectable in body fluids. We studied the composition and function of bacterial microbiota-derived EVs genes in urine to evaluate whether they have specific characteristics concerning allergic airway disease. Methods Subjects were from elementary school surveys and classified into 3 groups according to questionnaires and sensitization to aeroallergens: the allergic airway group (AA, n = 16), atopic controls (AC, n = 7) and healthy controls (HC, n = 26). The bacterial EVs were isolated from voided urine samples, their nucleic acid was extracted for 16S ribosomal RNA pyrosequencing and then characterized using α-diversity, β-diversity, network analysis, intergroup comparison of bacterial composition and predicted functions, and correlation with total immunoglobulin E (IgE), eosinophils% and fractional exhaled NO. Results The compositional α-diversity was the highest in AA, while functional α-diversity was the highest in HC. AA had a distinct clustering with the least intersample variation. Klebsiella , Haemophilus , members from Lachnospiraceae and Ruminococcaceae, and the pathways of sphingolipid and glycerolipid metabolism, and biosynthesis of peptidoglycan and lysine were the highest in AA and positively correlated with total IgE or eosinophil%. Genetic information processing function contributed to 48% of the intergroup variance and was the highest in AA. Diaphorobacter , Acinetobacter, and the pathways of short-chain fatty acids and anti-oxidants metabolism, lysine and xenobiotic degradation, and lipopolysaccharide biosynthesis were the lowest in AA and negatively correlated with total IgE or eosinophil%. The bacterial composition and function in AC were closer to those in HC. The bacterial network was remarkably dense in HC. Conclusions The bacterial microbiota-derived EVs in urine possess characteristic features in allergic airway disease with a remarkable correlation with total IgE and eosinophil%. These findings suggest that they may play important roles in allergic airway diseases.

The aim of this study was to investigate role of common pollen in Korean school-aged children with allergic rhinitis (AR) in 5 provinces (Incheon Metropolitan City-Gyeonggi Province, Chungcheongbuk-do, Gwangju Metropolitan City, Busan Metropolitan City, and Jeju Special Self-Governing Province), using a questionnaire and skin prick test, and to assess the differences among the residential regions. Among the enrolled 14,678 total children, 1,641 (22.0%) had AR. The sensitization rate to pollen (38.7%) was the second highest among examined allergens and significant differences were in the sensitization rates to trees, weeds, and grasses among the 5 provinces (P < 0.05). The sensitization to trees (25.2%) was the highest common among the pollen types and significant differences also were observed in the sensitization rates to alder, birch, Japanese cedar, oak, and elm among the 5 provinces. The sensitization rate to weeds (19.9%) was the second highest and significant differences were observed in the sensitization rate to Japanese hop, mugwort, and ragweed among the 5 provinces. The sensitization rate to house dust mite was 86.8%, the highest among examined allergens and that to Dermatophagoides farinae exhibited regional differences (P = 0.003) but not to D. farinae (P = 0.584). The sensitization rate to mold (13.5%) was the highest in Jeju and lowest in Busan, and a statistically significant difference was detected among the 5 provinces. These results support that examined pollen allergens are strongly associated with residential region due to regional causative pollen differences among children with AR within Korea to investigate the main pollen allergens.