Ji Tae Choung

Epidemiological Change of Atopic Dermatitis and Food Allergy in School-Aged Children in Korea between 1995 and 2000

Little is known about the prevalence of atopic dermatitis and food allergy outside North America and Europe. We evaluated the prevalence of atopic dermatitis and food allergy with the comparison of prevalence between 1995 and 2000 in Korea and evaluated the correlation of prevalence between atopic dermatitis and food allergy. A cross-sectional questionnaire survey was conducted on random samples of schoolchildren 6 to 14 yr at two time points, 1995 and 2000 throughout Korea. The last twelve months prevalence of atopic dermatitis in Korean school-aged children was increased from 1995 to 2000. The twelve-month prevalence of atopic dermatitis and food allergy were higher in Seoul than in any other provincial cities in 1995, but the prevalence of both diseases in Seoul and Provincial Centers became to be similar in 2000. The rate responded to food allergy of children with atopic dermatitis (9.5%) was lower than that of the western countries (60%). And our data demonstrated paternal and maternal allergy history is very significantly correlated to developing atopic dermatitis in their offspring. The further objective evaluations are required to confirm these outcomes because the environmental and risk factors may be different among the countries according to their living cultures.

Acute Effects of Asian Dust Events on Respiratory Symptoms and Peak Expiratory Flow in Children with Mild Asthma

The aim of this study was to investigate the possible adverse effects of Asian dust events on respiratory health in asthmatic children. Fifty-two children with mild asthma were studied for eight consecutive weeks in the spring of 2004 (March 8 to May 2). During the study period, five Asian dust days were identified; we included a lag period of two days following each of the events. Subjects recorded their respiratory symptom diaries and peak expiratory flow (PEF) twice daily during the study period; and they underwent methacholine bronchial challenge tests. The subjects reported a significantly higher frequency of respiratory symptoms during the Asian dust days than during the control days. They showed significantly more reduced morning and evening PEF values, and more increased PEF variability (10.1%±3.5% vs. 5.5%±2.2%) during the Asian dust days than during the control days. Methacholine PC20 was not significantly different between before and after the study period (geometric mean: 2.82 mg/mL vs. 3.16 mg/mL). These results suggest that the short-term Asian dust events might be associated with increased acute respiratory symptoms and changes in PEF outcomes. However, there might be little long-term influence on airway hyperresponsiveness in children with mild asthma.

Humidifier Disinfectant–associated Children’s Interstitial Lung Disease

RATIONALE Beginning in 2006, epidemics of a fatal lung injury of unknown cause in children were observed in Korea every spring. A recent study demonstrated that this type of childrens interstitial lung disease (chILD) is associated with humidifier disinfectant use. OBJECTIVES To determine the clinical characteristics of this type of chILD and to assess whether the nationwide suspension of humidifier disinfectant sales in the autumn of 2011 affected its incidence. METHODS The clinical characteristics of suspected cases between 2006 and 2011 were determined by a nationwide retrospective study. The potential causal relationship with humidifier disinfectants was examined by a prospective surveillance study after humidifier disinfectant sales were suspended. MEASUREMENTS AND MAIN RESULTS In total, 138 children were diagnosed with this type of chILD, which was characterized by rapid progression, high mortality, predominance in the spring season, and a familial tendency. The annual incidence increased in 2011 and then dropped to zero in 2012. The children were on average 30.4 months old. The most frequent symptoms at admission were cough and dyspnea. As the disease progressed, the typical complication was spontaneous air leak. Eighty children (58%) died. Two years after humidifier disinfectant-sale suspension, no more new cases were found. CONCLUSIONS This study suggests that humidifier disinfectant inhalation causes an idiopathic type of chILD that is characterized by spontaneous air leak, rapid progression, lack of response to treatment, and high mortality. Further safety studies must be performed on common environmental compounds, particularly those that enter the human body by an unusual route.

Clinical evaluation of the SD Bioline influenza virus antigen test for rapid detection of influenza viruses A and B in children and adults during the influenza season.

ABSTRACT The performance of the SD Bioline rapid antigen test kit for influenza virus detection was evaluated with 295 respiratory specimens during the influenza season. The overall sensitivity and specificity of the SD Bioline test were 61.9% and 96.8% for the influenza A virus antigen and 54.5% and 100% for the influenza B virus antigen, respectively. The results were consistent with peak influenza activities.

Increased Serum Interleukin-5 and Vascular Endothelial Growth Factor in Children With Acute Mycoplasma Pneumonia and Wheeze

Acute mycoplasma pneumonia may be accompanied by wheeze in some children considered not to have asthma. The aim of the present study was to evaluate cytokine secretion in children with acute mycoplasma pneumonia and wheeze. We studied 58 patients with mycoplasma pneumonia (12 with wheeze, Group 1; 46 without wheeze, Group 2) and 36 patients of non‐mycoplasma pneumonia (Group 3). Serum levels of interleukin (IL)‐4, IL‐5, interferon (IFN)‐γ, and vascular endothelial growth factor (VEGF) were measured using an enzyme‐linked immunosorbent assay kits. The mean ± SD IL‐5 level of Group 1 was 97.1 ± 73.0 pg/ml, which was significantly higher than that of Group 2 (28.2 ± 32.2 pg/ml) and that of Group 3 (35.7 ± 42.0 pg/ml). The mean ± SD VEGF level of Group 1 was 687.5 ± 385.8 pg/ml, which was significantly higher than that of Group 2 (310.0 ± 251.9 pg/ml) and that of Group 3 (402.3 ± 279.5 pg/ml). No significant differences in serum levels of IL‐4, IFN‐γ, and IgE were observed between the groups. Our results show that children with mycoplasma pneumonia and wheeze have significantly higher serum levels of IL‐5 and VEGF. These increased immune responses may be associated with the pathophysiological mechanisms by which the Mycoplasma pneumoniae contribute to the development of wheeze during acute mycoplasma pneumonia. Pediatr Pulmonol. 2009; 44:423–428.

The level of submicron fungal fragments in homes with asthmatic children

OBJECTIVES Much scientific evidence indicates a positive association between moldy environments and respiratory illnesses and/or symptoms (e.g., asthma). Recently, submicron fungal fragments (<1.0 μm) have been suggested as a potential contributor to adverse health effects due to their biological composition (e.g., antigens, mycotoxins, and (1,3)-β-D-glucan) as well as their small size. However, the contribution of exposure to fine fungal particles on adverse health outcomes has been poorly characterized, particularly in homes with asthmatic children. We characterized the airborne level of smaller-sized fungal particles between homes with and without asthmatic children. METHODS We visited 29 homes with (n=15) and without (n=14) an asthmatic child and sampled submicron fungal fragments in a living room and child׳s bedroom, along with outdoor sampling, using the NIOSH two-stage sampler. (1,3)-β-D-glucan of fungal fragments analyzed by Limulus Amebocyte lysate assay (LAL) was used for quantifying their exposure. RESULTS Overall, the geometric mean (GM) concentration of (1,3)-β-D-glucan in submicron fungal fragments in indoor air was two-fold higher in homes with asthmatic children (50.9 pg/m(3)) compared to homes with non-asthmatic children (26.7 pg/m(3)) (P<0.001). The GM concentration of these particles in child׳s bedroom in homes with an asthmatic child (66.1 pg/m(3)) was about three times higher than that in homes with non-asthmatic children (23.0 pg/m(3)) (P<0.001). The relative humidity had a negative correlation with the concentration of (1,3)-β-D-glucan in submicron fungal fragments (Pearson coefficient=-0.257, P=0.046). CONCLUSIONS Our findings indicate that homes with asthmatic children have a higher concentration of submicron fungal fragments compared to homes with non-asthmatic children. A greater exposure to smaller-sized fungal particles may occur in homes with an asthmatic child as relative humidity decreases. The very careful control of relative humidity in indoor air is necessary for reducing exposure to fine fungal particles and inhibiting the growth of microorganisms in homes with allergic diseases.

Comparison of cytokine responses in nasopharyngeal aspirates from children with viral lower respiratory tract infections.

Aim: To determine whether nasopharyngeal aspirates (NPAs) cytokine response is different according to the causative viruses in children with lower respiratory tract infections (LRTI).

Predictive value of C-reactive protein in response to macrolides in children with macrolide-resistant Mycoplasma pneumoniae pneumonia

Purpose The prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) has increased worldwide. The aim of this study was to estimate the proportion of MRMP in a tertiary hospital in Korea, and to find potential laboratory markers that could be used to predict the efficacy of macrolides in children with MRMP pneumonia. Methods A total of 95 patients with M. pneumoniae pneumonia were enrolled in this study. Detection of MRMP was based on the results of specific point mutations in domain V of the 23S rRNA gene. The medical records of these patients were reviewed retrospectively and the clinical course and laboratory data were compared. Results The proportion of patients with MRMP was 51.6% and all MRMP isolates had the A2063G point mutation. The MRMP group had longer hospital stay and febrile period after initiation of macrolides. The levels of serum C-reactive protein (CRP) and interleukin-18 in nasopharyngeal aspirate were significantly higher in patients who did not respond to macrolide treatment. CRP was the only significant factor in predicting the efficacy of macrolides in patients with MRMP pneumonia. The area under the curve for CRP was 0.69 in receiver operating characteristic curve analysis, indicating reasonable discriminative power, and the optimal cutoff value was 40.7 mg/L. Conclusion The proportion of patients with MRMP was high, suggesting that the prevalence of MRMP is rising rapidly in Korea. Serum CRP could be a useful marker for predicting the efficacy of macrolides and helping clinicians make better clinical decisions in children with MRMP pneumonia.

Relationships Between Exhaled Nitric Oxide and Atopy Profiles in Children With Asthma

Purpose We examined whether fractional exhaled nitric oxide (FeNO) levels are associated with atopy profiles in terms of mono-sensitization and poly-sensitization in asthmatic children. Methods A total of 119 children underwent an assessment that included FeNO measurements, spirometry, methacholine challenge, and measurement of blood eosinophil count, serum total IgE, and serum eosinophil cationic protein (ECP). We also examined sensitization to five classes of aeroallergens (house dust mites, animal danders, pollens, molds, and cockroach) using skin prick testing. The children were divided into three groups according to their sensitization profiles to these aeroallergens (non-sensitized, mono-sensitized, and poly-sensitized). Results The geometric means (range of 1 SD) of FeNO were significantly different between the three groups (non-sensitized, 18.6 ppb [10.0-34.7 ppb]; mono-sensitized, 28.8 ppb [16.6-50.1 ppb]; and poly-sensitized, 44.7 ppb [24.5-81.3 ppb], P=0.001). FeNO levels were correlated with serum total IgE concentrations, peripheral blood eosinophilia, and serum ECP levels to different degrees. Conclusions FeNO levels vary according to the profile of atopy, as determined by positive skin prick test results to various classes of aeroallergens. FeNO is also moderately correlated with serum total IgE, blood eosinophilia, and serum ECP. These results suggest that poly-sensitized asthmatic children may have the highest risk of airway inflammation.

Residential Environmental Risk Factors for Childhood Asthma Prevalence in Metropolitan and Semirural Cities in Korea

To identify the association between residential environmental risk factors and the prevalence of childhood asthma, the authors surveyed the prevalence of asthma, the residential environmental risk factors of 1819 elementary school students, and air pollution in metropolitan (Seongbuk), and semirural (Andong) areas. Although there was no significant difference in the prevalence of self-reported asthma (SA) between the 2 geographic areas (12.8% vs 13.6%), the prevalence of physician-diagnosed asthma (PDA) in Andong (15.0%) was significantly higher than that in Seongbuk (6.8%). After adjusting for confounding factors, logistic regression suggested that there were significant differences in size of the house (adjusted odds ratio [aOR] = 1.82), medical insurance (aOR = 2.59), and number of residents in the household (aOR = 1.54) between the SA and non-SA groups. There was a significant difference in the area of residence (aOR = 2.12) between the PDA and non-PDA groups. In conclusion, residential environmental risk factors and the area of residence affect the prevalence of childhood asthma.