Biological products in allergy practice: the beginning of a new era

Recently, the treatment of allergic diseases has significantly progressed with the development and increased use of biological products (BPs) or molecularly targeted drugs. Based on cases with asthma, using BPs in allergic diseases has expanded to include chronic rhinosinusitis with nasal polyps, atopic dermatitis, and chronic spontaneous urticaria.Current Concepts: BPs are effective in treating severe allergic diseases, which often have limitations with current treatments and limited therapeutic options available. The added efficacy of BPs includes reduced risk of side effects from using systemic corticosteroids. Additional to transforming clinical care, BPs have provided insights into disease mechanisms and identified biomarkers to predict therapeutic responses. This has opened a new era towards personalized and precise treatment.Discussion and Conclusion: BPs for patients with severe asthma reduce symptoms and risks of exacerbations. Because of these observations, whether the remission of allergic diseases can be achieved by BPs has been pondered. Another agonizing problem is that BPs are expensive and many patients require prolonged administration for disease control. As more BPs become available, costs will likely decrease, leading to their more widespread use. Indeed, a new era in the treatment of allergic diseases has begun.

Understanding the Molecular Mechanisms of Asthma through Transcriptomics

The transcriptome represents the complete set of RNA transcripts that are produced by the genome under a specific circumstance or in a specific cell. High-throughput methods, including microarray and bulk RNA sequencing, as well as recent advances in biostatistics based on machine learning approaches provides a quick and effective way of identifying novel genes and pathways related to asthma, which is a heterogeneous disease with diverse pathophysiological mechanisms. In this manuscript, we briefly review how to analyze transcriptome data and then provide a summary of recent transcriptome studies focusing on asthma pathogenesis and asthma drug responses. Studies reviewed here are classified into 2 classes based on the tissues utilized: blood and airway cells.

Risk Factors for Acute Exacerbations in Elderly Asthma: What Makes Asthma in Older Adults Distinctive?

PURPOSE: Asthma in the elderly (EA; ≥ 65 years of age) is increasing, adding a heavy socioeconomic burden to the healthcare system. However, little is known about risk factors associated with acute exacerbations in EA patients. The objective of this study was to investigate risk factors for acute exacerbation in EA compared to non-elderly asthma (NEA).METHODS: We combined data from 3 adult asthma cohorts under a unified protocol and database. Asthmatic patients with regular follow-up during a 1-year period were selected from the cohorts to identify the risk factors predicting acute exacerbations in EA compared to NEA.RESULTS: We selected a total of 1,086 patients from the merged cohort. During the observation period, 503 and 583 patients were assigned to the EA and NEA groups, respectively. The exacerbation rate was 31.0% in the EA and 33.2% in the NEA group. Multivariate logistic regression analysis revealed fixed airway obstruction, chronic rhinosinusitis (CRS), and male sex as independent risk factors for exacerbation in the EA group. In the NEA group, exacerbation increased along with an increase in eosinophil count. Bayesian analysis of the interactions among clinical factors revealed that forced expiratory volume in 1 second/forced vital capacity was directly related to exacerbation in the EA group, and eosinophil count was related to exacerbation in the NEA group.CONCLUSIONS: We suggest that fixed airway obstruction and CRS as the important clinical factors predicting acute exacerbations in EA, whereas in NEA, eosinophil count was the strong predictor of exacerbation.

Genetic Signatures of Acute Asthma Exacerbation Related With Ineffective Response to Corticosteroid

Purpose@#Acute exacerbation (AE) is an important domain of asthma management and may be related with ineffective response to corticosteroid. This study aimed to find mechanisms of AE using genome-wide gene expression profiles of blood cells from asthmatics and its perturbation by in vitro dexamethasone (Dex)-treatment. @*Methods@#We utilized lymphoblastoid B cells from 107 childhood asthmatics and peripheral blood mononuclear cells from 29 adult asthmatics who were treated with inhaled corticosteroids. We searched for a preserved co-expression gene module significantly associated with the AE rate in both cohorts and measured expression changes of genes belong to this module after Dex-treatment. @*Results@#We identified a preserved module composed of 77 genes. Among them, expressions of 2 genes (EIF2AK2 and NOL11) decreased significantly after Dex-treatment in both cohorts. EIF2AK2, a key gene acting antiviral defense mechanism, showed significantly higher expressions in asthmatics with AE. The protein repair pathway was enriched significantly in 64 genes which belong to the preserved module but showed no expression differences after Dex-treatment in both cohorts. Among them, MSRA and MSRB2 may play key roles by controlling oxidative stress. @*Conclusions@#Many genes belong to the AE rate-associated and preserved module identified in blood cells from childhood and adults asthmatics showed no expression changes after in vitro Dex-treatment. These findings suggest that we may need alternative treatment options to corticosteroids to prevent AE. EIF2AK2, MSRA and MSRB2 expressions on blood cells may help us select AE-susceptible asthmatics and adjust treatments to prevent AE.

Genetic Signatures of Acute Asthma Exacerbation Related With Ineffective Response to Corticosteroid

Purpose@#Acute exacerbation (AE) is an important domain of asthma management and may be related with ineffective response to corticosteroid. This study aimed to find mechanisms of AE using genome-wide gene expression profiles of blood cells from asthmatics and its perturbation by in vitro dexamethasone (Dex)-treatment. @*Methods@#We utilized lymphoblastoid B cells from 107 childhood asthmatics and peripheral blood mononuclear cells from 29 adult asthmatics who were treated with inhaled corticosteroids. We searched for a preserved co-expression gene module significantly associated with the AE rate in both cohorts and measured expression changes of genes belong to this module after Dex-treatment. @*Results@#We identified a preserved module composed of 77 genes. Among them, expressions of 2 genes (EIF2AK2 and NOL11) decreased significantly after Dex-treatment in both cohorts. EIF2AK2, a key gene acting antiviral defense mechanism, showed significantly higher expressions in asthmatics with AE. The protein repair pathway was enriched significantly in 64 genes which belong to the preserved module but showed no expression differences after Dex-treatment in both cohorts. Among them, MSRA and MSRB2 may play key roles by controlling oxidative stress. @*Conclusions@#Many genes belong to the AE rate-associated and preserved module identified in blood cells from childhood and adults asthmatics showed no expression changes after in vitro Dex-treatment. These findings suggest that we may need alternative treatment options to corticosteroids to prevent AE. EIF2AK2, MSRA and MSRB2 expressions on blood cells may help us select AE-susceptible asthmatics and adjust treatments to prevent AE.

Characteristics of Adult Severe Refractory Asthma in Korea Analyzed From the Severe Asthma Registry

PURPOSE: Although mild to moderate asthma is much more common, the morbidity and mortality of severe asthma are much higher. This study was performed to identify and analyze the clinical characteristics of severe asthma in Korea. METHODS: We registered patients with severe refractory asthma into the Severe Asthma Registry supported by the Severe Asthma Work Group of the Korean Academy of Asthma, Allergy and Clinical Immunology. Patients were enrolled since 2010 from the 15 university hospitals nationwide in Korea. Severe asthma was defined according to modified European Respiratory Society/American Thoracic Society criteria. Information on demographics, medical history, pulmonary function tests and skin prick tests was collected; the clinical characteristics of severe asthmatics were analyzed from the collected data. RESULTS: A total of 489 patients were enrolled with a mean age of 62.3; 45% are male. Sixty percent of patients received Global Initiative for Asthma step 4 treatment, and 30% received step 5 treatment. The most common comorbidities were allergic rhinitis (58.7%). Aspirin hypersensitivity was observed in 14.0%. Approximately half (53.9%) are non-smokers. Atopy was proven in 38.5% of the patients. Regarding asthma medications, inhaled corticosteroids and long-acting β-agonist combination inhalers were most commonly prescribed (96.5%), followed by leukotriene antagonists (71.0%). A recombinant anti-immunoglobulin E monoclonal antibody (omalizumab) has been used in 1.8% of the patients. The mean forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and FEV1/FVC were 78.7%, 67.5% and 67.9% of predicted values, respectively. The mean Asthma Control Test and quality of life questionnaire scores were 16.5 out of 25 and 59.5 out of 85, respectively. CONCLUSIONS: The baseline characteristics of severe asthma patients in the Korea Severe Asthma Registry were analyzed and reported for the first time. With this cohort, further prospective studies should be performed to search for ways to improve management of severe refractory asthma.

Different Biological Pathways Are Up-regulated in the Elderly With Asthma: Sputum Transcriptomic Analysis

BACKGROUND: Elderly asthma (EA) is increasing, but the pathogenesis is unclear. This study aimed to identify EA-related biological pathways by analyzing genome-wide gene expression profiles in sputum cells. METHODS: A total of 3,156 gene probes with significantly differential expressions between EA and healthy elderly controls were used for a hierarchical clustering of genes to identify gene clusters. Gene set enrichment analysis provided biological information, with replication from Gene Expression Omnibus expression profiles. RESULTS: Fifty-five EA patients and 10 elderly control subjects were enrolled. Two distinct gene clusters were found. Cluster 1 (n = 35) showed a lower eosinophil proportion in sputum and less severe airway obstruction compared to cluster 2 (n = 20). The replication data set also identified 2 gene clusters (clusters 1' and 2'). Among 5 gene sets significantly enriched in cluster 1 and 3 gene sets significantly enriched in cluster 2, we confirmed that 2 were significantly enriched in the replication data set (OXIDATIVE_PHOSPHORYLATION gene set in cluster 1 and EPITHELIAL MESENCHYMAL TRANSITION gene set in cluster 2'). CONCLUSIONS: The findings of 2 distinct gene clusters in EA and different biological pathways in each gene cluster suggest 2 different pathogenesis mechanisms underlying EA.

The Fas Signaling Pathway Is a Common Genetic Risk Factor for Severe Cutaneous Drug Adverse Reactions Across Diverse Drugs

PURPOSE: Human leukocyte antigen (HLA) has been recognized as the most important genetic risk factor for severe cutaneous adverse drug reactions (SCARs) caused by certain drugs. However, cumulated observations suggest the presence of genetic risk factors for SCARs other than drug-specific HLA. We aimed to identify a common genetic risk factor of SCARs across multiple drugs. METHODS: We performed 2 independent genome-wide association studies (GWASs). A total of 68 and 38 subjects with a diagnosis of SCAR were enrolled in each GWAS. Their allele frequencies were compared to those of healthy subjects in Korea. RESULTS: No single nucleotide polymorphism (SNP) with genome-wide significance was found in either GWAS. We next selected and annotated the 200 top-ranked SNPs from each GWAS. These 2 sets of annotated genes were then entered into the web interface of ConsensusPathDB for a pathway-level analysis. The Fas signaling pathway was significantly over-represented in each gene set from the 2 GWASs. CONCLUSIONS: Our observations suggest that the Fas signaling pathway may be a common genetic risk factor for SCARs across multiple drugs.

Oral Allergy Syndrome in Birch Pollen-Sensitized Patients from a Korean University Hospital

BACKGROUND: Oral allergy syndrome (OAS) is a type of allergic reaction that mainly occurs on oral contact with raw fruit, vegetables, or nuts. The most common type of OAS is birch pollen-related food allergy. Although OAS is a common food allergy in adults, only few epidemiologic studies have been reported in Korea. Here we investigate the prevalence and triggers of birch pollen-related food allergy. METHODS: We conducted a retrospective chart review of 1,427 patients who underwent a skin prick test for inhalant allergens at the Asthma and Allergy Clinic in Seoul National University Bundang Hospital from January 2011 to December 2016. RESULTS: Of 1,427 patients, 125 (8.7%) were sensitized to birch pollen. Among them, 20.0% developed OAS, which was the most common food allergy (96.2%). The prevalence of OAS was higher in females, and was 18.2% in birch pollen-sensitized allergic rhinoconjunctivitis patients. Further, 72.0% OAS patients had rhinoconjunctivitis, 20.0% had asthma, and 12.0% had chronic urticaria. Apple (68.0%), peach (56.0%), nuts (36.0%), kiwi (20.0%), persimmon (20.0%), plum (16.0%), and cherry (16.0%) were frequent triggers; however, Chinese yam, kudzu vine, bellflower root, codonopsis, and ginseng were also revealed as triggers. Patients (60.0%) showed OAS with ≥ 3 foods at the same time. Only 3 patients showed mono-sensitivity to birch pollen, while others were multi-sensitized to trees, grasses, weed, or house dust mite allergens. CONCLUSION: OAS was the most common food allergy in birch pollen-sensitized patients. This study revealed the unique triggers of OAS in Korea in addition to well-known triggers.

Multifaceted interventions to reduce acute exacerbations in elderly asthmatics

BACKGROUND: Although many risk factors are known to be associated with poor asthma outcomes in the elderly, the literature on the effect of risk factor control on asthma outcomes in the elderly is very sparse. OBJECTIVE: To evaluate the role of multifaceted interventions in reducing acute exacerbations in elderly asthmatics. METHODS: A total of 100 subjects were randomly selected from our prospective cohort of elderly asthmatics aged 65 years or older and were provided multifaceted intervention for 1 year. Our multifaceted interventions included repeated education on asthma and inhaler technique for patients and their caregivers, provision of an action plan to cope with acute exacerbations, short message service to prevent follow-up losses, and oral replacement of magnesium. The primary outcome was an acute asthma exacerbation rate compared to the previous year. RESULTS: Ninety-two subjects completed this study, although only 58 subjects continued to take magnesium. Compared to the previous year, the acute asthma exacerbation rate showed a significant reduction from 67% to 50% (p = 0001) and significant improvement was observed in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) (p = 0.04, p = 0.036 for each). Interestingly, a subgroup analysis revealed that predicted value of FEV1 increased significantly in subjects who continued to take magnesium from 79.6% to 87.1% (p = 0.008). CONCLUSION: To reduce acute exacerbations in elderly asthmatics, a multifaceted approach in increase medical awareness, proficiency and adherence to inhaler, assistance of caregivers and correction of micronutrients deficiency is likely to be effective. In addition, a continuous oral replacement of magnesium may increase FEV1 in elderly asthmatics.

Perceptions of Severe Asthma and Asthma-COPD Overlap Syndrome Among Specialists: A Questionnaire Survey

PURPOSE: Severe asthma and asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) are difficult to control and are often associated with poor clinical outcomes. However, much is not understood regarding the diagnosis and treatment of severe asthma and ACOS. To evaluate the current perceptions of severe asthma and COPD among asthma and COPD specialists, we designed an e-mail and internet-based questionnaire survey. METHODS: Subjects were selected based on clinical specialty from among the members of the Korean Academy of Asthma, Allergy and Clinical Immunology and the Korean Academy of Tuberculosis and Respiratory Diseases. Of 432 subjects who received an e-mail invitation to the survey, 95 subjects, including 58 allergists and 37 pulmonologists, responded and submitted their answers online. RESULTS: The specialists estimated that the percentage of severe cases among total asthma patients in their practice was 13.9%±11.0%. Asthma aggravation by stepping down treatment was the most common subtype, followed by frequent exacerbation, uncontrolled asthma despite higher treatment steps, and serious exacerbation. ACOS was estimated to account for 20.7% of asthma, 38.0% of severe asthma, and 30.1% of COPD cases. A history of smoking, persistently low forced expiratory volume in 1 second (FEV1), and low FEV1 variation were most frequently classified as the major criteria for the diagnosis of ACOS among asthma patients. Among COPD patients, the highly selected major criteria for ACOS were high FEV1 variation, positive bronchodilator response, a personal history of allergies and positive airway hyperresponsiveness. Allergists and pulmonologists showed different assessments and opinions on asthma phenotyping, percentage, and diagnostic criteria for ACOS. CONCLUSIONS: Specialists had diverse perceptions and clinical practices regarding severe asthma and ACOS patients. This heterogeneity must be considered in future studies and strategy development for severe asthma and ACOS.

The virtual asthma guideline e-learning program: learning effectiveness and user satisfaction

BACKGROUND/AIMS: Effective educational tools are important for increasing adherence to asthma guidelines and clinical improvement of asthma patients. We developed a computer-based interactive education program for asthma guideline named the Virtual Learning Center for Asthma Management (VLCAM). We evaluated the usefulness of program in terms of its effects on user awareness of asthma guideline and level of satisfaction. METHODS: Physicians-in-training at tertiary hospitals in Korea were enrolled in a cross-sectional questionnaire survey. The e-learning program on asthma guideline was conducted over a 2-week period. We investigated changes in the awareness of asthma guideline using 35-item self-administered questionnaire aiming at assessing physicians' knowledge, attitude, and practice. Satisfaction with the program was scored on 4-point Likert scales. RESULTS: A total of 158 physicians-in-training at six tertiary hospitals completed the survey. Compared with baseline, the overall awareness obtained from the scores of knowledge, attitude, and practice was improved significantly. Participants were satisfied with the VLCAM program in the following aspects: helpfulness, convenience, motivation, effectiveness, physicians' confidence, improvement of asthma management, and willingness to recommend. All items in user satisfaction questionnaires received high scores over 3 points. Moreover, the problem-based learning with a virtual patient received the highest user satisfaction among all parts of the program. CONCLUSIONS: Our computer-based e-learning program is useful for improving awareness of asthma management. It could improve adherence to asthma guidelines and enhance the quality of asthma care.

Real-Life Clinical Use of Symbicort® Maintenance and Reliever Therapy for Asthmatic Patients in Korea

The aim of this study was to examine the daily practice patterns of Symbicort® Maintenance and Reliever Therapy (SMART) in Korean asthmatic patients and to analyze clinical signs related to overuse. This study used an observational, multicenter, noninterventional, prospective, uncontrolled design for examining asthmatic patients prescribed SMART to assess the frequency and pattern of Symbicort® usage as a maintenance and reliever medication. The characteristics of patients showing signs of overuse (frequency of inhalation: 8 or more times per day) were also analyzed. Among the 1,518 patients analyzed, 1,292 (85.1%) completed the trial. The number of mean inhalations per day was 2.14±1.15; the number of patients who had at least 1 as needed usage (PRN) inhalation per day was 843 (55.5%); the mean frequency of PRN use was 0.25±0.67 inhalations per day. The number of patients who overused for at least 1 day was 260 (17.1%). In particular, young patients, patients with limited physical activity, and patients with nocturnal symptoms demonstrated high frequency of overuse. The frequency of overuse during SMART was not high in Korean asthmatic patients and the asthma status of follow-up outpatients improved overall. However, there is a need for careful education targeted toward younger patients, patients with limited physical activity, and patients with nocturnal symptoms owing to their tendency to frequently overuse.

Fixed Food Eruption Caused by Actinidia arguta (Hardy Kiwi): A Case Report and Literature Review

Fixed drug eruption (FDE) is a common hypersensitivity reaction characterized by recurrent, well-circumscribed, erythematous patches that arise at the same site as a result of systemic drug exposure. However, fixed food eruption (FFE), a lesion triggered by food ingestion, is a rare allergy that was first defined in 1996. Based on their anti-inflammatory and anti-oxidant properties, the fruit and leaves of Actinidia arguta, the hardy kiwi, are widely consumed across Korea, Japan, and China. This report describes the first case of FFE caused by hardy kiwi leaves, known as Daraesun in Korean, confirmed by oral provocation tests and skin biopsy.

Genetic Signatures of Asthma Exacerbation

Asthma exacerbation (AE) usually denotes worsening of asthma symptoms that requires intense management to prevent further deterioration. AE has been reported to correlate with clinical and demographic factors, such as race, gender, and treatment compliance as well as environmental factors, such as viral infection, smoking, and air pollution. In addition, recent observations suggest that there are likely to be genetic factors specific to AE. Understanding genetic factors specific to AE is essential to develop therapy tailored for exacerbation-prone asthma. Here, we summarize the results of studies involving genetic risk factors for AE. To simplify and enhance understanding, we reviewed the studies according to the following categories: hypothesis-driven approaches, hypothesis-free approaches, gene-environment interactions, and pharmacogenetics.

Serum micronutrients levels and clinical features of elderly asthmatics

PURPOSE: The prevalence of asthma in the elderly is rapidly increasing. However, we do not fully understand the pathogenesis of elderly asthma, especially for the roles of micronutrients. This study aimed to evaluate the associations between serum levels of micronutrients, including several vitamins and minerals, and clinical features of the elderly asthmatics. METHODS: A total of 317 asthmatics aged 65 or older were enrolled. Serum levels of vitamin D, vitamin B₁₂, folate, Mg, and Se were measured and then the associations between serum micronutrient levels and clinical features of elderly asthmatics were evaluated. RESULTS: Positive correlations with significance among serum levels of vitamin B₁₂, vitamin D, and folate were found. Serum micronutrients levels showed no difference according to the atopic status and symptom severity. The serum folate level was significantly associated with forced expiratory volume in 1 second, and serum vitamin B₁₂ and folate levels were significantly associated with serum total IgE level. Interestingly, elderly asthmatics with exacerbation history showed significantly lower serum levels of vitamin D and Mg, but significantly higher serum levels of Se. CONCLUSION: Serum levels of micronutrients, such as vitamin D, vitamin B₁₂, Mg, folate, and Se, were significantly associated with some clinical features of elderly asthmatics. Clinical meanings of these associations need to be investigated further.

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.

The efficacy of single premedication with antihistamines for radiocontrast media hypersensitivity

BACKGROUND: Single premedication with antihistamines for radiocontrast media (RCM) hypersensitivity is frequently used in real world at the emergent situation although its efficacy is not proven. OBJECTIVE: To evaluate the effect of intravenous antihistamines as a premedication in general population who had experience of mild adverse reactions to iodinated RCM. METHODS: A retrospective observational study on 14,785 subjects who had RCM-enhanced computed tomography scans between January 2014 and December 2015 in Seoul National University Hospital Gangnam Healthcare Center, Seoul, South Korea. RESULTS: Among 453 subjects who had a history of mild RCM-induced hypersensitivity reactions, 273 subjects had a single premedication of intravenous antihistamine. When comparing antihistamine-premedication group and nonpremedication group, there is no protective effect of antihistamines on the incidence rate and severity of hypersensitivity (10.6% vs. 11.7%, p = 0.729). CONCLUSION: The clinical efficacy of a single premedication of antihistamines for mild RCM-induced hypersensitivity was not confirmed.

Defining Chronic Cough: A Systematic Review of the Epidemiological Literature

PURPOSE: Recent evidence suggests a global burden of chronic cough in general populations. However, the definitions vary greatly among epidemiological studies, and none have been validated for clinical relevance. We aimed to examine previous epidemiological definitions in detail and explore the operational characteristics. METHODS: A systematic review was conducted for epidemiological surveys that reported the prevalence of chronic cough in general adult populations during the years 1980 to 2013. A literature search was performed on Pubmed and Embase without language restriction. Epidemiological definitions for chronic cough were classified according to their components, such as cutoff duration. Meta-analyses were performed for the male-to-female ratio of chronic cough prevalence to explore operational characteristics of epidemiological definitions. RESULTS: A total of 70 studies were included in the systematic review. The most common epidemiological definition was identified as 'cough > or =3 months' duration without specification of phlegm (n=50); however, it conflicted with the cutoff duration in current clinical guidelines (cough > or =8 weeks). Meta-analyses were performed for the male-to-female ratio of chronic cough among 28 studies that reported sex-specific prevalence using the most common definition. The pooled male-to-female odds ratio was 1.26 (95% confidence interval 0.92-1.73) with significant heterogeneity (I2=96%, P<0.001), which was in contrast to clinical observations of female predominance from specialist clinics. Subgroup analyses did not reverse the ratio or reduce the heterogeneity. CONCLUSIONS: This study identified major issues in defining chronic cough in future epidemiological studies. The conflict between epidemiological and clinical diagnostic criteria needs to be resolved. The unexpected difference in the gender predominance between the community and clinics warrants further studies. Clinical validation of the existing definition is required.

Lung Microbiome Analysis in Steroid-Naїve Asthma Patients by Using Whole Sputum / 결핵및호흡기질환

BACKGROUND: Although recent metagenomic approaches have characterized the distinguished microbial compositions in airways of asthmatics, these results did not reach a consensus due to the small sample size, non-standardization of specimens and medication status. We conducted a metagenomics approach by using terminal restriction fragment length polymorphism (T-RFLP) analysis of the induced whole sputum representing both the cellular and fluid phases in a relative large number of steroid naïve asthmatics. METHODS: Induced whole sputum samples obtained from 36 healthy subjects and 89 steroid-naїve asthma patients were analyzed through T-RFLP analysis. RESULTS: In contrast to previous reports about microbiota in the asthmatic airways, the diversity of microbial composition was not significantly different between the controls and asthma patients (p=0.937). In an analysis of similarities, the global R-value showed a statistically significant difference but a very low separation (0.148, p=0.002). The dissimilarity in the bacterial communities between groups was 28.74%, and operational taxonomic units (OTUs) contributing to this difference were as follows: OTU 789 (Lachnospiraceae), 517 (Comamonadaceae, Acetobacteraceae , and Chloroplast), 633 (Prevotella), 645 (Actinobacteria and Propionibacterium acnes), 607 (Lactobacillus buchneri, Lactobacillus otakiensis, Lactobacillus sunkii, and Rhodobacteraceae), and 661 (Acinetobacter, Pseudomonas, and Leptotrichiaceae), and they were significantly more prevalent in the sputum of asthma patients than in the sputum of the controls. CONCLUSION: Before starting anti-asthmatic treatment, the microbiota in the whole sputum of patients with asthma showed a marginal difference from the microbiota in the whole sputum of the controls.