Watcharoot Kanchongkittiphon

Indoor Environmental Exposures and Exacerbation of Asthma: An Update to the 2000 Review by the Institute of Medicine

Background: Previous research has found relationships between specific indoor environmental exposures and exacerbation of asthma. Objectives: In this review we provide an updated summary of knowledge from the scientific literature on indoor exposures and exacerbation of asthma. Methods: Peer-reviewed articles published from 2000 to 2013 on indoor exposures and exacerbation of asthma were identified through PubMed, from reference lists, and from authors’ files. Articles that focused on modifiable indoor exposures in relation to frequency or severity of exacerbation of asthma were selected for review. Research findings were reviewed and summarized with consideration of the strength of the evidence. Results: Sixty-nine eligible articles were included. Major changed conclusions include a causal relationship with exacerbation for indoor dampness or dampness-related agents (in children); associations with exacerbation for dampness or dampness-related agents (in adults), endotoxin, and environmental tobacco smoke (in preschool children); and limited or suggestive evidence for association with exacerbation for indoor culturable Penicillium or total fungi, nitrogen dioxide, rodents (nonoccupational), feather/down pillows (protective relative to synthetic bedding), and (regardless of specific sensitization) dust mite, cockroach, dog, and dampness-related agents. Discussion: This review, incorporating evidence reported since 2000, increases the strength of evidence linking many indoor factors to the exacerbation of asthma. Conclusions should be considered provisional until all available evidence is examined more thoroughly. Conclusion: Multiple indoor exposures, especially dampness-related agents, merit increased attention to prevent exacerbation of asthma, possibly even in nonsensitized individuals. Additional research to establish causality and evaluate interventions is needed for these and other indoor exposures. Citation: Kanchongkittiphon W, Mendell MJ, Gaffin JM, Wang G, Phipatanakul W. 2015. Indoor environmental exposures and exacerbation of asthma: an update to the 2000 review by the Institute of Medicine. Environ Health Perspect 123:6–20; http://dx.doi.org/10.1289/ehp.1307922

High Susceptibility of Human Dendritic Cells to Avian Influenza H5N1 Virus Infection and Protection by IFN-α and TLR Ligands

There is worldwide concern that the avian influenza H5N1 virus, with a mortality rate of >50%, might cause the next influenza pandemic. Unlike most other influenza infections, H5N1 infection causes a systemic disease. The underlying mechanisms for this effect are still unclear. In this study, we investigate the interplay between avian influenza H5N1 and human dendritic cells (DC). We showed that H5N1 virus can infect and replicate in monocyte-derived and blood myeloid DC, leading to cell death. These results suggest that H5N1 escapes viral-specific immunity, and could disseminate via DC. In contrast, blood pDC were resistant to infection and produced high amounts of IFN-α. Addition of this cytokine to monocyte-derived DC or pretreatment with TLR ligands protected against infection and the cytopathic effects of H5N1 virus.

Childhood asthma and obesity—what is the true link?

Obesity rates have increased significantly in children in many parts of the world, especially in North America.1 According to data from the most recent National Health and Nutrition Examination Survey, approximately 17% (or 12.5 million) of US children and adolescents 2 to 9 years old are obese.2 The impact that childhood obesity has on pediatric diseases has become a major prevention initiative by the Obama administration and several public health organizations. Children with obesity are at increased risk for developing asthma, one of the most common chronic diseases in children.3 Childhood asthma accounts for more than 14 million missed school days per year and is the primary cause of school absences in the United States.4 A relation between obesity and asthma is supported by prospective studies in adults and children suggesting that being overweight and obese can precede the onset of asthma5 and studies in adults showing alleviation of asthma symptoms with weight loss.6 Despite consistent evidence linking obesity to the incidence and prevalence of asthma and several postulated hypotheses to explain this association, a definitive mechanism remains a mystery. Genetic and Environmental Factors Asthma and obesity are likely to be connected in a multifactorial fashion. Although genetic susceptibility can contribute to the development of asthma and obesity, the rapid increase in a relatively short period suggests that changes in lifestyle, such as diet, physical activity, early life exposures, and other environmental interactions, also can play a role. Epigenetic mechanisms associated with obesity and asthma have been proposed. Obesity and asthma likely have their beginnings in utero and in early childhood. Diet and nutrition, especially prenatal and early infant diet, may play a part in these diseases. Greater consumption of fruits and vegetables, antioxidants, minerals and vitamins, fish, and legumes during pregnancy seems to confer protection against childhood asthma and wheeze7 and may influence the neonatal immune system and lung development.8 However, 1 study showed that fatty acid dietary supplementation during pregnancy did not lower the overall incidence of asthma.9 To further support the idea that intrauterine nutrition is important, associations between low birth weight and resulting obesity and asthma have been shown. In 1 study, low birth weight led to the development of asthma and excess body mass increased the risk.10 Rapid growth in body mass index (BMI) during the first 2 years of life increased the risk of asthma up to 6 years of age based on published data from 8 European birth cohorts.11

Perinatal and early childhood environmental factors influencing allergic asthma immunopathogenesis.

BACKGROUND The prevalence of asthma has increased dramatically over the past several decades. While hereditary factors are highly important, the rapid rise outstrips the pace of genomic variation. Great emphasis has been placed on potential modifiable early life exposures leading to childhood asthma. METHODS We reviewed the recent medical literature for important studies discussing the role of the perinatal and early childhood exposures and the inception of childhood asthma. RESULTS AND DISCUSSION Early life exposure to allergens (house dust mite (HDM), furred pets, cockroach, rodent and mold), air pollution (nitrogen dioxide (NO(2)), ozone (O(3)), volatile organic compounds (VOCs), and particulate matter (PM)) and viral respiratory tract infections (Respiratory syncytial virus (RSV) and human rhinovirus (hRV)) has been implicated in the development of asthma in high risk children. Conversely, exposure to microbial diversity in the perinatal period may diminish the development of atopy and asthma symptoms.

Impact of school peanut-free policies on epinephrine administration

Background Children with food allergies spend a large proportion of time in school but characteristics of allergic reactions in schools are not well studied. Some schools self‐designate as peanut‐free or have peanut‐free areas, but the impact of policies on clinical outcomes has not been evaluated. Objective We sought to determine the effect of peanut‐free policies on rates of epinephrine administration for allergic reactions in Massachusetts public schools. Methods In this retrospective study, we analyzed (1) rates of epinephrine administration in all Massachusetts public schools and (2) Massachusetts public school nurse survey reports of school peanut‐free policies from 2006 to 2011 and whether schools self‐designated as “peanut‐free” based on policies. Rates of epinephrine administration were compared for schools with or without peanut‐restrictive policies. Results The percentage of schools with peanut‐restrictive policies did not change significantly in the study time frame. There was variability in policies used by schools self‐designated as peanut‐free. No policy was associated with complete absence of allergic reactions. Both self‐designated peanut‐free schools and schools banning peanuts from being served in school or brought from home reported allergic reactions to nuts. Policies restricting peanuts from home, served in schools, or having peanut‐free classrooms did not affect epinephrine administration rates. Schools with peanut‐free tables, compared to without, had lower rates of epinephrine administration (incidence rate per 10,000 students 0.2 and 0.6, respectively, P = .009). Conclusions These data provide a basis for evidence‐based school policies for children with food allergies. Further studies are required before decisions can be made regarding peanut‐free policies in schools.

Child with Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by pruritic skin lesions, disrupted skin barrier function, dysregulation of the immune system, and allergic reactions to food and environmental allergens. It generally presents in early childhood. Scratching at the area of pruritis leads to redness, cracking, scaling and potential superinfection of the skin. Most AD patients have personal or family history of atopy (allergic rhinitis, allergic conjunctivitis, AD or asthma). The differential diagnosis of AD is listed in Table 1. Table 1 Differential diagnosis of Atopic Dermatitis34,35 Data from the National Survey of Children’s Health in the United States demonstrates a wide range of prevalence from 8.7% to 18.1% in various locales with the higher prevalence reported in the east coast states.1 In Europe, 10% to 20% of children and teenagers are affected by AD.2 Approximately 50% of patients develop this disease during first year of life and 30% between the ages of 1–5 years.3

Reprint of: Perinatal and early childhood environmental factors influencing allergic asthma immunopathogenesis.

BACKGROUND The prevalence of asthma has increased dramatically over the past several decades. While hereditary factors are highly important, the rapid rise outstrips the pace of genomic variation. Great emphasis has been placed on potential modifiable early life exposures leading to childhood asthma. METHODS We reviewed the recent medical literature for important studies discussing the role of the perinatal and early childhood exposures and the inception of childhood asthma. RESULTS AND DISCUSSION Early life exposure to allergens (house dust mite (HDM), furred pets, cockroach, rodent and mold), air pollution (nitrogen dioxide (NO2), ozone (O3), volatile organic compounds (VOCs), and particulate matter (PM)) and viral respiratory tract infections (Respiratory syncytial virus (RSV) and human rhinovirus (hRV)) has been implicated in the development of asthma in high risk children. Conversely, exposure to microbial diversity in the perinatal period may diminish the development of atopy and asthma symptoms.

Exhaled Volatile Organic Compounds Predict Exacerbations of Childhood Asthma in a 1-Year Prospective Study

CM Robroeks, JJ van Berkel, Q Jobsis. Eur Respir J. 2013;42(1):98–106 The goal of this study was to investigate whether exhaled volatile organic compounds (VOCs) in exhaled breath are able to predict asthma exacerbations and to assess which combination of VOCs is the most predictive. Children with asthma aged 6 to 16 years from the outpatient clinic of the Department of Pediatric Pulmonology, Maastricht University Medical Centre, were included. All children were known to have had a …

Factors Associated With Elevated Exhaled Nitric Oxide Fraction in Infants With Recurrent Respiratory Symptoms

A Kotaniemi-Syrjanen, LP Malmberg, K Malmstrom, AS Pelkonen, MJ Makela. Eur Respir J. 2013;41(1):189–194 To evaluate the relationship between exhaled nitric oxide fraction (FeNO) and increased airway responsiveness, and to clarify whether there are any associations between these measures and risk factors for respiratory morbidity in infants with recurrent lower respiratory tract symptoms. Studied subjects were 444 children aged <3years with recurrent lower respiratory tract symptoms including wheeze, dry or productive cough, and/or shortness of breath. Subjects were assessed for FeNO, lung function tests, and the …