Lung Disease Diagnostic Model Through IgG Sensitization to Microbial Extracellular Vesicles

Purpose@#Recently, there has been a rise in the interest to understand the composition of indoor dust due to its association with lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) and lung cancer. Furthermore, it has been found that bacterial extracellular vesicles (EVs) within indoor dust particles can induce pulmonary inflammation, suggesting that these might play a role in lung disease. @*Methods@#We performed microbiome analysis of indoor dust EVs isolated from mattresses in apartments and hospitals. We developed diagnostic models based on the bacterial EVs antibodies detected in serum samples via enzyme-linked immunosorbent assay (ELISA) in this analysis. @*Results@#Proteobacteria was the most abundant bacterial EV taxa observed at the phylum level while Pseudomonas, Enterobacteriaceae (f) and Acinetobacter were the most prominent organisms at the genus level, followed by Staphylococcus. Based on the microbiome analysis, serum anti-bacterial EV immunoglobulin G (IgG), IgG1 and IgG4 were analyzed using ELISA with EV antibodies that targeted Staphylococcus aureus, Acinetobacter baumannii, Enterobacter cloacae and Pseudomonas aeruginosa. The levels of anti-bacterial EV antibodies were found to be significantly higher in patients with asthma, COPD and lung cancer compared to the healthy control group. We then developed a diagnostic model through logistic regression of antibodies that showed significant differences between groups with smoking history as a covariate. Four different variable selection methods were compared to construct an optimal diagnostic model with area under the curves ranging from 0.72 to 0.81. @*Conclusions@#The results of this study suggest that ELISA-based analysis of anti-bacterial EV antibodies titers can be used as a diagnostic tool for lung disease. The present findings provide insights into the pathogenesis of lung disease as well as a foundation for developing a novel diagnostic methodology that synergizes microbial EV metagenomics and immune assays.

Lung Disease Diagnostic Model Through IgG Sensitization to Microbial Extracellular Vesicles

Purpose@#Recently, there has been a rise in the interest to understand the composition of indoor dust due to its association with lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) and lung cancer. Furthermore, it has been found that bacterial extracellular vesicles (EVs) within indoor dust particles can induce pulmonary inflammation, suggesting that these might play a role in lung disease. @*Methods@#We performed microbiome analysis of indoor dust EVs isolated from mattresses in apartments and hospitals. We developed diagnostic models based on the bacterial EVs antibodies detected in serum samples via enzyme-linked immunosorbent assay (ELISA) in this analysis. @*Results@#Proteobacteria was the most abundant bacterial EV taxa observed at the phylum level while Pseudomonas, Enterobacteriaceae (f) and Acinetobacter were the most prominent organisms at the genus level, followed by Staphylococcus. Based on the microbiome analysis, serum anti-bacterial EV immunoglobulin G (IgG), IgG1 and IgG4 were analyzed using ELISA with EV antibodies that targeted Staphylococcus aureus, Acinetobacter baumannii, Enterobacter cloacae and Pseudomonas aeruginosa. The levels of anti-bacterial EV antibodies were found to be significantly higher in patients with asthma, COPD and lung cancer compared to the healthy control group. We then developed a diagnostic model through logistic regression of antibodies that showed significant differences between groups with smoking history as a covariate. Four different variable selection methods were compared to construct an optimal diagnostic model with area under the curves ranging from 0.72 to 0.81. @*Conclusions@#The results of this study suggest that ELISA-based analysis of anti-bacterial EV antibodies titers can be used as a diagnostic tool for lung disease. The present findings provide insights into the pathogenesis of lung disease as well as a foundation for developing a novel diagnostic methodology that synergizes microbial EV metagenomics and immune assays.

The Effects of Short-Term and Very Short-Term Particulate Matter Exposure on Asthma-Related Hospital Visits: National Health Insurance Data

PURPOSE: The purpose of this study was to investigate the effects of short-term and very short-term exposure to particulate matter (PM) exceeding the daily average environmental standards for Korea (≤100 µg/m³ for PM₁₀ and ≤50 µg/m³ for PM(2.5)) on on asthma-related hospital visits. MATERIALS AND METHODS: This was a population-based, case-crossover study using National Health Insurance and air pollution data between January 1, 2014 and December 31, 2016. The event day was defined as a day when PM exceeded the daily average environmental standard (short-term exposure) or daily average environmental standard for 2 hours (very short-term exposure). The control day was defined as the same day of the week at 1 week prior to the event day. RESULTS: Compared with control days, asthma-related hospital visits on the 24-hr event days and 2-hr event days increased by 4.10% and 3.45% for PM₁₀ and 5.66% and 3.74% for PM(2.5), respectively. Asthma-related hospital visits increased from the 24-hr event day for PM₁₀ to 4 days after the event day, peaking on the third day after the event day (1.26, 95% confidence interval, 1.22–1.30). Hospitalizations also increased on the third day after the event. While there was a difference in magnitude, PM(2.5) exposure showed similar trends to PM₁₀ exposure. CONCLUSION: We found a significant association between short-term and very short-term PM exposure exceeding the current daily average environmental standards of Korea and asthma-related hospital visits. These results are expected to aid in establishing appropriate environmental standards and relevant policies for PM.

How to Apply the Concept of Cough Hypersensitivity in Clinical Practice?

No abstract available.

Severe Cutaneous Adverse Reactions to Antiepileptic Drugs: A Nationwide Registry-Based Study in Korea

PURPOSE: Severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) to antiepileptic drug (AED), are rare, but result in significant morbidity and mortality. We investigated the major culprit drugs, clinical characteristics, and clinical course and outcomes of AED-induced SCARs using a nationwide registry in Korea. METHODS: A total of 161 patients with AED-induced SCARs from 28 referral hospitals were analyzed. The causative AEDs, clinical characteristics, organ involvements, details of treatment, and outcomes were evaluated. We compared the clinical and laboratory parameters between SJS/TEN and DRESS according to the leading causative drugs. We further determined risk factors for prolonged hospitalization in AED-induced SCARs. RESULTS: Carbamazepine and lamotrigine were the most common culprit drugs causing SCARs. Valproic acid and levetiracetam also emerged as the major causative agents. The disease duration and hospital stay in carbamazepine-induced SJS/TEN were shorter than those in other AEDs (P< 0.05, respectively). In younger patients, lamotrigine caused higher incidences of DRESS than other drugs (P= 0.045). Carbamazepine, the most common culprit drug for SCARs, was associated with a favorable outcome related with prolonged hospitalization in SJS (odds ratio, 0.12; 95% confidence interval, 0.02-0.63, P= 0.12), and thrombocytopenia was found to be a risk factor for prolonged hospitalization in DRESS. CONCLUSION: This was the first large-scale epidemiological study of AED-induced SCARs in Korea. Valproic acid and levetiracetam were the significant emerging AEDs causing SCARs in addition to the well-known offending AEDs such as carbamazepine and lamotrigine. Carbamazepine was associated with reduced hospitalization, but thrombocytopenia was a risk factor for prolonged hospitalization. Our results suggest that the clinical characteristics and clinical courses of AED-induced SCARs might vary according to the individual AEDs.

Phenotypes of Severe Cutaneous Adverse Reactions Caused by Nonsteroidal Anti-inflammatory Drugs

PURPOSE: Nonsteroidal anti-inflammatory drugs (NSAIDs) are common cause of severe cutaneous adverse reactions (SCARs). The present study aimed to investigate the characteristics of SCARs induced by NSAIDs in the Korean SCAR registry. METHODS: A retrospective survey of NSAID-induced SCARs recorded between 2010 and 2015 at 27 university hospitals in Korea was conducted. Clinical phenotypes of SCARs were classified into Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), SJS-TEN overlap syndrome and drug reaction with eosinophilia and systemic symptoms (DRESS). Causative NSAIDs were classified into 7 groups according to their chemical properties: acetaminophen, and propionic, acetic, salicylic, fenamic and enolic acids. RESULTS: A total of 170 SCARs, consisting of 85 SJS, 32 TEN, 17 SJS-TEN overlap syndrome and 36 DRESS reactions, were induced by NSAIDs: propionic acids (n=68), acetaminophen (n=38), acetic acids (n=23), salicylic acids (n=16), coxibs (n=8), fenamic acids (n=7), enolic acids (n=5) and unclassified (n=5). Acetic acids (22%) and coxibs (14%) accounted for higher portions of DRESS than other SCARs. The phenotypes of SCARs induced by both propionic and salicylic acids were similar (SJS, TEN and DRESS, in order). Acetaminophen was primarily associated with SJS (27%) and was less involved in TEN (10%). DRESS occurred more readily among subjects experiencing coxib-induced SCARs than other NSAID-induced SCARs (62.5% vs. 19.7%, P = 0.013). The mean time to symptom onset was longer in DRESS than in SJS or TEN (19.1 ± 4.1 vs. 6.8 ±1.5 vs. 12.1 ± 3.8 days). SCARs caused by propionic salicylic acids showed longer latency, whereas acetaminophen- and acetic acid-induced SCARs appeared within shorter intervals. CONCLUSIONS: The present study indicates that the phenotypes of SCARs may differ according to the chemical classifications of NSAIDs. To establish the mechanisms and incidences of NSAID-induced SCARs, further prospective studies are needed.

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.

KAAACI Evidence-Based Clinical Practice Guidelines for Chronic Cough in Adults and Children in Korea

Chronic cough is common in the community and causes significant morbidity. Several factors may underlie this problem, but comorbid conditions located at sensory nerve endings that regulate the cough reflex, including rhinitis, rhinosinusitis, asthma, eosinophilic bronchitis, and gastroesophageal reflux disease, are considered important. However, chronic cough is frequently non-specific and accompanied by not easily identifiable causes during the initial evaluation. Therefore, there are unmet needs for developing empirical treatment and practical diagnostic approaches that can be applied in primary clinics. Meanwhile, in referral clinics, a considerable proportion of adult patients with chronic cough are unexplained or refractory to conventional treatment. The present clinical practice guidelines aim to address major clinical questions regarding empirical treatment, practical diagnostic tools for non-specific chronic cough, and available therapeutic options for chronic wet cough in children and unexplained chronic cough in adults in Korea.

Akkermansia muciniphila-derived extracellular vesicles influence gut permeability through the regulation of tight junctions

The gut microbiota has an important role in the gut barrier, inflammation and metabolic functions. Studies have identified a close association between the intestinal barrier and metabolic diseases, including obesity and type 2 diabetes (T2D). Recently, Akkermansia muciniphila has been reported as a beneficial bacterium that reduces gut barrier disruption and insulin resistance. Here we evaluated the role of A. muciniphila-derived extracellular vesicles (AmEVs) in the regulation of gut permeability. We found that there are more AmEVs in the fecal samples of healthy controls compared with those of patients with T2D. In addition, AmEV administration enhanced tight junction function, reduced body weight gain and improved glucose tolerance in high-fat diet (HFD)-induced diabetic mice. To test the direct effect of AmEVs on human epithelial cells, cultured Caco-2 cells were treated with these vesicles. AmEVs decreased the gut permeability of lipopolysaccharide-treated Caco-2 cells, whereas Escherichia coli-derived EVs had no significant effect. Interestingly, the expression of occludin was increased by AmEV treatment. Overall, these results imply that AmEVs may act as a functional moiety for controlling gut permeability and that the regulation of intestinal barrier integrity can improve metabolic functions in HFD-fed mice.

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.

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.

Is Omalizumab a Problem-Solving Remedy in Severe Asthma?

No abstract available.

Importance of indoor dust biological ultrafine particles in the pathogenesis of chronic inflammatory lung diseases

The role of infectious agents in the etiology of inflammatory diseases once believed to be non-infectious is increasingly being recognized. Many bacterial components in the indoor dust can evoke inflammatory lung diseases. Bacteria secrete nanometer-sized vesicles into the extracellular milieu, so-called extracellular vesicles (EV). which are pathophysiologically related to inflammatory diseases. Microbiota compositions in the indoor dust revealed the presence of both Gram-negative and Gram-positive bacteria. Escherichia coli is a model organism of Gram-negative Enterobacteriaceae. The repeated inhalation of E. coli-derived EVs caused neutrophilic inflammation and emphysema in a dose-dependent manner. The emphysema induced by E. coli-derived EVs was partially eliminated by the absence of Interferon-gamma or interleukin-17, suggesting that Th1 and/or Th17 cell responses are important in the emphysema development. Meanwhile, the repeated inhalation of Staphylococcus aureus-derived EVs did not induce emphysema, although they induced neutrophilic inflammation in the lung. In terms of microbial EV compositions in the indoor dust, genera Pseudomonas, Acinetobacter, Enterobacter, and Staphylococcus were dominant. As for the clinical significance of sensitization to EVs in the indoor dust, EV sensitization was closely associated with asthma, chronic obstructive pulmonary disorder (COPD), and lung cancer. These data indicate that biological ultrafine particles in the indoor dust, which are mainly composed of microbial EVs, are important in the pathogenesis of chronic lung diseases associated with neutrophilic inflammation. Taken together, microbial EVs in the indoor dust are an important diagnostic and therapeutic target for the control of chronic lung diseases, such as asthma, COPD, and lung cancer.

Genetic polymorphisms of interleukin-10 and transforming growth factor-β1 and antituberculosis drugs-induced liver injury

PURPOSE: Drug-induced liver injury is one of the serious adverse reactions resulting in severe morbidity and discontinuation of medications. Previously, IL-10 gene polymorphism has been reported to be associated with diclofenac-induced hepatitis. In this study, we aimed to investigate the associations between genetic polymorphisms of immune-regulating cytokines (IL-10 and TGF-β1) with antituberculosis drugs (ATD)-induced liver injury. METHODS: We enrolled 80 patients with ATD-induced liver injury and 238 ATD-tolerant controls. Two single nucleotide polymorphisms (SNP) of IL-10 (-1082A>G, rs1800896; -819T>C, rs1800871) and one promoter SNP of TGF-β1 gene (-509C>T, rs1800469) were genotyped in both groups. Genotype frequencies of these SNPs were compared between case and control groups. RESULTS: In 2 promoter SNPs of IL-10 gene, there was no significant difference of genotype frequencies between patients with ATD-induced liver injury and controls. In addition, the genotype frequency of TGF-β1 -509C>T SNP in ATD-induced liver injury patients were not different from those of controls. CONCLUSION: In conclusion, there was no significant association between IL-10 and TGF-β1 gene polymorphisms and ATD-induced liver injury. These findings suggest that IL-10 and TGF-β1 do not play important role in the development of ATD-induced liver injury.

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.

House Dust Mite-Derived Chitin Enhances Th2 Cell Response to Inhaled Allergens, Mainly via a TNF-α-Dependent Pathway

PURPOSE: Chitin is a potent adjuvant in the development of immune response to inhaled allergens in the airways. According to other studies, chitin is known as multi-faced adjuvants which can induce Th2 responses. Recently, we found that TNF-α is a key mediator in the development of Th2 cell response to inhaled allergens. Here, we evaluated the immunologic mechanisms in the development of airway hypersensitivity to inhaled allergens, enhanced by house dust mite (HDM)-derived chitin. METHODS: The role of TNF-α and TLRs was evaluated in an airway hypersensitivity mouse model induced by a sensitization with an allergen (ovalbumin, OVA) and HDM-derived chitin using mice with the null mutation of target genes. RESULTS: The present study showed that airway sensitization with HDM-derived chitin plus OVA enhanced OVA-induced airway inflammation v. OVA alone. This phenotype was associated with the increased expression of Th1, Th2, and Th17 cytokines and also with the enhanced production of OVA-specific IgE, IgG1, and IgG2a. As for T cell responses, OVA-specific Th2 cell response, enhanced by chitin, was abolished by the treatment of chitinase, whereas Th1 and Th17 cell responses enhanced by this treatment. Moreover, the null mutation of the TNF-α gene revealed similar effects as the chitinase treatment. In contrast, all the OVA-specific T cell responses, enhanced by chitin, were blocked by the absence of TLR2, but not of TLR1, TLR4, or TLR6. CONCLUSIONS: In conclusion, these data suggest that HDM-derived chitin may enhance airway hypersensitivity to inhaled allergens, via the TLR2-dependent pathway, and that chitin-induced TNF-α can be a key mediator in the development of Th2 cell response to inhaled allergens.

Methazolamide-induced toxic epidermal necrolysis confirmed by lymphocyte activation test

Among various dermatological entities, toxic epidermal necrolysis (TEN) is a rare but potentially fatal delayed hypersensitivity reaction to numerous medications. A 38-year-old male presented with systemic hypersensitivity reaction, such as high fever, pain in the eyes, and diffuse pruritic erythematous maculopapular eruptions with multiple targetoid plaques that became vesicular and bullous. Oral mucosa and conjunctivae were involved. The first sign appeared about 1 week after taking methazolamide (50 mg twice a day) for the management of glaucomatous eyes. Although methazolamide was discontinued, blistering and skin denudation progressed to affect up to 80% of the body surface area and a positive Nikolsky sign was noted. High fever also persisted. Skin lesions started to improve after 2 weeks of management and fever subsided. Cutaneous lesions improved with minimal permanent sequele 2 months later. HLA-B*5901 was found by high-resolution genotyping. The lymphocyte activation test performed 6 months after remission showed a positive response to methazolamide challenge. This is the first case of methazolamide-induced TEN in which methazolamide was confirmed as a culprit drug by the lymphocyte activation test.

16S rRNA gene-based metagenomic analysis reveals differences in bacteria-derived extracellular vesicles in the urine of pregnant and non-pregnant women

Recent evidence has indicated that bacteria-derived extracellular vesicles (EVs) are important for host–microbe communication. The aims of the present study were to evaluate whether bacteria-derived EVs are excreted via the urinary tract and to compare the composition of bacteria-derived EVs in the urine of pregnant and non-pregnant women. Seventy-three non-pregnant and seventy-four pregnant women were enrolled from Dankook University and Ewha Womans University hospitals. DNA was extracted from urine EVs after EV isolation using the differential centrifugation method. 16S ribosomal RNA (16S rRNA) gene sequencing was performed using high-throughput 454 pyrosequencing after amplification of the V1–V3 region of the 16S rDNA. The composition of 13 taxa differed significantly between the pregnant and non-pregnant women. At the genus level, Bacillus spp. EVs were more significantly enriched in the urine of the pregnant women than in that of the non-pregnant women (45.61% vs 0.12%, respectively). However, Pseudomonas spp. EVs were more dominant in non-pregnant women than in pregnant women (13.2% vs 4.09%, respectively). Regarding the compositional difference between pregnant women with normal and preterm delivery, EVs derived from Ureaplasma spp. and the family Veillonellaceae (including Megasphaera spp.) were more abundant in the urine of preterm-delivered women than in that of women with normal deliveries. Taken together, these data showed that Bacillus spp. EVs predominate in the urine of pregnant women, whereas Pseudomonas spp. EVs predominate in the urine of non-pregnant women; this suggests that Bacillus spp. EVs might have an important role in the maintenance of pregnancy.