The connection between early life wheezing and subsequent asthma: The viral march
ABSTRACT Several new lines of evidence suggest that alterations in immune responses which predispose to bronchial obstruction during acute respiratory infection, especially with rhinoviruses, may explain to a considerable extent the link between early life wheezing and subsequent asthma; above all among those schoolchildren who are prone to having recurrent asthma exacerbations. The nature of these alterations is currently the subject of considerable scrutiny, but cross-sectional studies suggest that deficits in innate immune responses mediated by interferon type I and III are present in lung macrophages and epithelial cells of adult asthmatics. Similarly, long-term follow-up studies suggest that deficits in interferon gamma responses in the first year of life predispose to recurrent episodes of wheezing from the preschool years and into early adolescence. A better understanding of the "viral march" could yield new therapeutic approaches for the prevention and treatment of acute severe airway obstruction during childhood. Several longitudinal studies have provided convincing evidence that, in most cases of asthma, the first symptoms of the disease occur during the preschool years.(1-3) Young children who will go on to develop asthma later in life usually have recurrent episodes of wheezing, cough, and difficulty to breathe ("persistent wheezers"),(4) and these episodes are associated with molecular evidence of viral respiratory infection in up to 90% of cases.(5) However, the majority of infants aged <1 year who wheeze remit by the age of 3 (the so-called transient wheezers(6)), and their episodes are also associated with viral infections. Until very recently, a predisposition to allergy was the main disease mechanisms believed to connect early life wheezing with subsequent asthma.(7) The purpose of this brief comment is to review the evidence which suggests that susceptibility to infection with rhinovirus may be a critical additional factor explaining this connection.
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- "The age group where asthma symptoms where most frequent in both surveys is the 1–4 year old group. It is likely that some of these symptoms correspond to wheezing episodes associated with respiratory viral infections early in life ; recent evidence, however, also suggest that bronchial obstruction during acute respiratory infection in childhood is clearly associated with subsequent asthma, especially among school-aged children at risk for repeated asthma exacerbations , making it relevant to quantify and to include in epidemiological studies. In the current survey we found an increase in current asthma symptoms for those subjects 5–17 years of age. "
ABSTRACT: While it is suggested that the prevalence of asthma in developed countries may have stabilized, this is not clear in currently developing countries. Current available information for both adults and children simultaneously on the burden and impact of allergic conditions in Colombia and in many Latin American countries is limited. The objectives of this study were to estimate the prevalence for asthma, allergic rhinitis (AR), atopic eczema (AE), and atopy in six colombian cities; to quantify costs to the patient and her/his family; and to determine levels of Immunoglobulin E (IgE) in asthmatic and healthy subjects. We conducted a cross-sectional, population-based study in six cities during the academic year 2009-2010. We used a school-based design for subjects between 5-17 years old. We carried out a community-based strategy for subjects between 1-4 years old and adults between 18-59 years old. Serum samples for total and antigen-specific (IgE) levels were collected using a population-based, nested, case-control design. We obtained information on 5978 subjects. The largest sample of subjects was collected in Bogotá (2392). The current prevalence of asthma symptoms was 12% (95% CI, 10.5-13.7), with 43% (95% CI, 36.3-49.2) reporting having required an emergency department visit or hospitalization in the past 12 months. Physician diagnosed asthma was 7% (95% CI, 6.1-8.0). The current prevalence of AR symptoms was 32% (95% CI, 29.5-33.9), and of AE symptoms was 14% (95% CI, 12.5-15.3). We collected blood samples from 855 subjects; 60.2% of asthmatics and 40.6% of controls could be classified as atopic. In Colombia, symptom prevalence for asthma, AR and AE, as well as levels of atopy, are substantial. Specifically for asthma, symptom severity and absence from work or study due to symptoms are important. These primary care sensitive conditions remain an unmet public health burden in developing countries such as Colombia.BMC Pulmonary Medicine 05/2012; 12(1):17. DOI:10.1186/1471-2466-12-17 · 2.49 Impact Factor
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ABSTRACT: Epidemiologic associations between viral lower respiratory infections (LRIs) and asthma in later childhood are well known. However, the question of whether such infections cause asthma or unmask asthma in a susceptible host has still not been settled. Most early evidence centered on the role of the respiratory syncytial virus; however, recent studies highlight a potential role for human rhinovirus as a risk factor for asthma. The links between early-life viral LRI and subsequent asthma are generally via wheeze; however, the presence of wheeze does not give any information about why the child is wheezing. Wheeze in early life is, at best, a fuzzy phenotype and not specific for subsequent asthma. The risk of asthma after viral LRI is increased in the presence of allergic sensitization in early life and if the infection is more severe. Atopy-associated mechanisms also appear to be involved in viral-induced acute exacerbations of asthma, especially in prolonging symptomatology after the virus has been cleared from the lungs. Breaking the nexus between viral respiratory infections and asthma may be possible with interventions designed to inhibit atopy-related effectors mechanisms from participating in the host response to respiratory viral infections.The Journal of allergy and clinical immunology 03/2010; 125(6):1202-5. DOI:10.1016/j.jaci.2010.01.024 · 11.25 Impact Factor
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ABSTRACT: Childhood asthma is a widespread health problem because of its epidemic prevalence, as asthma affects more than 300 million people worldwide. Results from cross-sectional and cohort studies show that asthma starts in childhood in a large proportion of cases. A proper diagnosis is easier to make in adults and school-age children, as permanent changes in lung development, the strong impact of environmental factors on the airways, the immunologic maturity process, and the use of some diagnostic tools make asthma more difficult to diagnose in preschool children. This period of a child's life is an interesting challenge for pediatricians and specialists. The aim of the present review is to analyze the current knowledge regarding making an early and accurate asthma diagnosis and therefore deciding on the correct treatment to gain control over asthma symptoms and minimize health risks.Current Allergy and Asthma Reports 10/2010; 11(1):71-7. DOI:10.1007/s11882-010-0156-5 · 2.45 Impact Factor