Sung Chul Seo

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.

Association between sensitization to mold and impaired pulmonary function in children with asthma

Purpose Recent data indicate that sensitization to mold contributes to the severity and persistence of asthma. In this study, we investigated the relationships between sensitization to mold and lung function parameters in children with asthma. Methods We retrospectively reviewed clinical data from 551 asthmatic subjects. We selected subjects who met clinical diagnostic criteria of asthma. Their spirometry, methacholine challenge tests, and measurements of blood eosinophils, serum IgE, eosinophil cationic protein (ECP) and fractional exhaled nitric oxide (FeNO) results were included. Skin prick testing (SPT) results with 13 common aeroallergens in Korea including house dust mites, animal dander, pollen, cockroach and mold were reviewed. Subjects were divided into 3 groups according to their SPT results. Subjects who showed no positive result to any aeroallergen were designated as group 1 (non-sensitized). Group 2 represented subjects who were sensitized to aeroallergens other than mold (other allergen-sensitized) and group 3 included subjects who were sensitized to mold allergens (mold-sensitized). Results Among the 551 asthmatic subjects, 67 (12.2%) were sensitized to mold and 366 (66.4%) were sensitized to other aeroallergens. The log mean IgE levels were higher in groups 2 (5.96±1.14 IU/mL) and 3 (5.81±0.97 IU/mL) compared to group 1 (3.88±1.68 IU/mL). Blood eosinophils, ECP and FeNO concentrations were significantly higher in groups 2 and 3, but no significant difference was found between the 2 groups. The mean FEV1 value was significantly lower in group 3 (86.9±12.1%pred) than in groups 2 (92.0±14.8%pred) and 1 (93.4±15.4%pred). The log mean methacholine PC20 was significantly lower in group 3 (0.08±1.91 mg/mL) than in groups 2 (1.31±1.69 mg/mL) and 1 (2.29±1.66 mg/mL). Conclusions We observed a differential association between mold and other aeroallergen sensitization, and severity of asthma. Sensitization to mold is associated with lower lung function and increased airway hyper-responsiveness in children with asthma. Mold sensitization could be an important factor determining asthma severity particularly airflow limitation in children.

Exploring Household-level Risk Factors for Self-reported Prevalence of Allergic Diseases Among Low-income Households in Seoul, Korea

Purpose Indoor risk factors for allergic diseases in low-income households in Korea have been characterized only partially. We evaluated the prevalences of atopic dermatitis, asthma, and allergic rhinitis in Seoul, Korea, to identify key housing and behavioral risk factors of low-income households. Methods Statistical analysis of the prevalence of these diseases and various risk factors was conducted using data from a 2010 Ministry of Environment household survey. Logistic regression models were generated using data from 511 low-income household apartments in districts of Seoul. Results In general, housing factors such as renovation history (P<0.1) and crowding status (P<0.01) were associated with allergic rhinitis, whereas behavioral factors such as frequency of indoor ventilation (P<0.05) and cleaning (P<0.1) were inversely correlated with atopic dermatitis. Indoor smoking was a major trigger of asthma and atopic dermatitis in low-income households (P<0.05). The presence of mold and water leakage in houses were the most important risk factors for all three diseases (P<0.05). Conclusions Various risk factors play a role in triggering allergic diseases among low-income households in Seoul, and health or environmental programs mitigating allergic diseases should be tailored to address appropriate housing or behavioral factors in target populations.

Bronchodilator responses after methacholine and adenosine 5'-monophosphate (AMP) challenges in children with asthma: their relationships with eosinophil markers.

Background. Bronchodilator responsiveness (BDR) and eosinophilic inflammation are characteristic features of asthma. Objective. The aim of this study was to compare the relationships of BDR after methacholine challenge or adenosine 5′-monophosphate (AMP) challenge to blood eosinophil markers in children with asthma. Methods. Methacholine and AMP challenges were performed on 69 children with mild intermittent to moderate persistent asthma. BDR was calculated as the change in forced expiratory volume in 1 second, expressed as percentage change of the value immediately after the each challenge and the value after inhalation of salbutamol. Serum total IgE levels, blood eosinophil counts, and serum eosinophil cationic protein (ECP) levels were determined for each subject. Results. A positive relationship between serum total IgE levels and BDR was found only after the AMP challenge (R2 = 0.345, p = .001) rather than after the methacholine challenge (R2 = 0.007, p = .495). Peripheral blood eosinophil counts correlated more significantly with BDR after AMP challenge (R2 = 0.212, p = .001) than BDR after methacholine challenge (R2 = 0.002, p = .724). Both BDR after methacholine challenge (R2 = 0.063, p = .038) and BDR after AMP challenge (R2 = 0.192, p = .001) were significantly correlated with serum ECP levels. Conclusion. BDR after AMP challenge may be more closely related to eosinophilic inflammation, compared with that after methacholine challenge.