11
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Genetic associations with asthma and virus-induced wheezing: a systematic review Translated title: Associação genética da asma e da sibilância induzida por vírus: uma revisão sistemática

      rapid-communication

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Various wheezing phenotypes can be identified based on differences in natural histories, risk factors and responses to treatment. In epidemiologic studies, atopic asthma or virus-induced wheezing can be discriminated by the presence or the absence of sensitization to allergens. Children with asthma have been shown to present lower levels of lung function. Patients with viral respiratory infections evolve from normal lung function to enhanced airway reactivity. The objective of this study was to identify genes and polymorphisms associated with different wheezing phenotypes. Using data obtained from the Genetic Association Database, we systematically reviewed studies on genes and polymorphisms that have been associated with virus-induced wheezing or atopic asthma. The research was carried out in February of 2009. Genes associated with the studied outcomes in more than three studies were included in the analysis. We found that different genes and loci have been associated with virus-induced wheezing or atopic asthma. Virus-induced wheezing has frequently been associated with IL-8 polymorphisms, whereas atopic asthma and atopy have frequently been associated with Th2 cytokine gene (CD14 and IL-13) polymorphisms on chromosome 5. This review provides evidence that different wheezing disorders in childhood can be differently affected by genetic variations, considering their role on airway inflammation and atopy. Future studies of genetic associations should consider the different wheezing phenotypes in infancy. In addition, stratified analyses for atopy can be useful for elucidating the mechanisms of the disease.

          Translated abstract

          Diversos fenótipos de sibilância têm sido identificados com base em diferenças na história natural, fatores de risco e resposta ao tratamento. Em estudos epidemiológicos, a asma atópica ou sibilância induzida por vírus pode ser discriminada pela presença ou ausência de sensibilização a alérgenos. As crianças com asma apresentam níveis menores de função pulmonar. Pacientes com infecções respiratórias virais apresentam-se com função pulmonar normal, mas mostram reatividade da via aérea aumentada. O objetivo deste trabalho foi identificar genes e polimorfismos associados aos diferentes fenótipos de sibilância. Utilizando dados do Genetic Association Database, foi realizada uma revisão sistemática de estudos sobre genes e polimorfismos associados à sibilância induzida por vírus ou à asma atópica. O levantamento foi realizado em fevereiro de 2009. Todos os genes associados com o desfecho estudado presentes em mais de três estudos foram incluídos na análise. Identificamos que diferentes genes e locos têm sido associados à sibilância induzida por vírus ou à asma atópica. Enquanto a sibilância induzida por vírus foi mais frequentemente associada a polimorfismos no gene IL-8, polimorfismos localizados em genes de citocinas Th2 no cromossomo 5 (CD14 e IL-13) foram frequentemente associados à atopia ou à asma atópica. Esta revisão mostrou evidências de que a sibilância na infância pode ser afetada por variações genéticas de formas diferentes, dependendo de seu papel na inflamação das vias aéreas e na atopia. Estudos futuros de associação genética deverão levar em consideração os diferentes fenótipos na infância. Além disso, análises estratificadas para atopia podem ser úteis para elucidar os mecanismos da doença.

          Related collections

          Most cited references52

          • Record: found
          • Abstract: found
          • Article: not found

          Perennial allergen sensitisation early in life and chronic asthma in children: a birth cohort study.

          Reduced lung function is a feature of chronic asthma, which becomes apparent at school age. Unknown factors between birth and school age determine the progressive loss of pulmonary function in children with persistent asthma. We investigated the role of allergic sensitisation and allergen exposure early in life. The German Multicentre Allergy Study followed 1314 children from birth to 13 years of age. We regularly interviewed parents about their child's asthma and measured IgE levels. Allergen exposure was assessed at age 6 months, 18 months, and at 3, 4, and 5 years; lung function was assessed at 7, 10, and 13 years; post-bronchodilator response at 10 and 13 years; and a bronchial histamine challenge was done at 7 years. 90% of children with wheeze but no atopy lost their symptoms at school age and retained normal lung function at puberty. By contrast, sensitisation to perennial allergens (eg, house dust mite, cat and dog hair) developing in the first 3 years of life was associated with a loss of lung function at school age. Concomitant exposure to high levels of perennial allergens early in life aggravated this process: forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) ratio was 87.4 (SD 7.4) for those sensitised and with high exposure compared with 92.6 (6.0) for those not sensitised, p<0.0001; and maximal expiratory flow at 50% (MEF50) 86.4 (25.1) for sensitised and with high exposure compared with 101.5 (23.2; p=0.0031) for those not sensitised. Such exposure also enhanced the development of airway hyper-responsiveness in sensitised children with wheeze. Sensitisation and exposure later in life had much weaker effects and sensitisation to seasonal allergens did not play a part. The chronic course of asthma characterised by airway hyper-responsiveness and impairment of lung function at school age is determined by continuing allergic airway inflammation beginning in the first 3 years of life. However, children with a non-atopic wheezing phenotype lose their symptoms over school age and retain normal lung function at puberty.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Interleukin-8 secretion and neutrophil recruitment accompanies induced sputum eosinophil activation in children with acute asthma.

            Although airway inflammation is recognized as a key feature of asthma, the characteristics of airway inflammation in children with acute severe asthma are not well defined. The aim of this study was to describe the characteristics of airway inflammation in children with an acute exacerbation of asthma using sputum cell counts and fluid-phase measurements and to examine the changes in these parameters upon resolution of the exacerbation. Children (n = 38) presenting to the Emergency Department with acute asthma underwent successful sputum induction using ultrasonically nebulized normal saline (n = 22), or expectorated sputum spontaneously (n = 16). Sputum induction was repeated at least 2 wk later when the children had recovered (n = 28). Sputum portions were selected, dispersed and total and differential cell counts performed. Neutrophil elastase and EG2-positive eosinophils were assessed and fluid-phase eosinophil cationic protein (ECP), myeloperoxidase (MPO), interleukin-8 (IL-8), and IL-5 were measured. During the acute exacerbation the median (range) total cell count was 8.4 x 10(6)/ml (0.5 to 190.3), and fell significantly at resolution to 1.3 x 10(6)/ml (p < 0.01). The inflammatory cell infiltrate was mixed and included eosinophils (0.8 x 10(6)/ml), neutrophils (3.3 x 10(6)/ml), and mast cells. EG2(+) cells were high and correlated with the degree of airflow obstruction (r = -0.5, p = 0.02). They decreased significantly at resolution as did supernatant ECP (1,078 versus 272 ng/ml), suggesting that eosinophils were activated during the exacerbation. MPO was 220 ng/ ml at exacerbation and fell significantly to 1 ng/ml at resolution. Levels of IL-8 and IL-5 were elevated during the acute exacerbation and IL-8 concentrations decreased at resolution. In conclusion, airway inflammation can be studied in children with acute asthma by sputum induction. Airway inflammation is present during an acute exacerbation of asthma, and is characterized by infiltration and activation of both eosinophils and neutrophils. The heterogeneity of airway inflammation in acute asthma may influence response to corticosteroid therapy.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Impact of IL8 and IL8-Receptor alpha polymorphisms on the genetics of bronchial asthma and severe RSV infections

              Background Interleukin 8 (IL8) belongs to the family of chemokines. It mediates the activation and migration of neutrophils from peripheral blood into tissue and hereby plays a pivotal role in the initiation of inflammation. Thus it is important in inflammatory lung diseases like bronchial asthma or severe infections by Respiratory Syncytial Virus (RSV). IL8 acts through binding to the IL8-Receptor alpha (IL8RA). For both genes association with asthma has been described. In addition, IL8 has been found in association with RSV bronchiolitis. The aim of our study was to test both genes for association with asthma and severe RSV infections. In addition we were interested in whether a common genetic background of both diseases exists in regards to these genes. Methods We genotyped the two IL8 promotor polymorphisms -251A/T and -781C/T and the three amino acid variants M31R, S276T and R335C in IL8RA on 322 children with asthma, 131 infants with severe RSV associated diseases and 270 controls. Statistical analyses made use of the Armitage's trend test for single polymorphisms and FAMHAP for calculations of haplotypes. Results We found association of the IL8 polymorphism -781C/T as well as IL8 haplotypes with asthma (p = 0.011 and p = 0.036, respectively). In addition, direct comparison of the asthmatic population with the RSV population revealed significant differences, both for -781C/T alone (p = 0.034) and IL8 haplotypes (p = 0.005). The amino acid variants in IL8RA were evenly distributed in between all three populations. Conclusion We conclude from our data that IL8 might play a role in the genetic predisposition to asthma and that these effects are different or even opposite to the effects on severe RSV diseases. Furthermore, IL8RA is unlikely to play a major role in the genetics of either disease.
                Bookmark

                Author and article information

                Contributors
                Role: ND
                Role: ND
                Role: ND
                Journal
                jbpneu
                Jornal Brasileiro de Pneumologia
                J. bras. pneumol.
                Sociedade Brasileira de Pneumologia e Tisiologia (São Paulo )
                1806-3756
                December 2009
                : 35
                : 12
                : 1220-1226
                Affiliations
                [1 ] Pontifícia Universidade Católica do Rio Grande do Sul Brazil
                [2 ] Universidade Estadual de Campinas Brazil
                Article
                S1806-37132009001200010
                10.1590/S1806-37132009001200010
                4de35581-0130-479d-a5cf-8d05e22b128d

                http://creativecommons.org/licenses/by/4.0/

                History
                Product

                SciELO Brazil

                Self URI (journal page): http://www.scielo.br/scielo.php?script=sci_serial&pid=1806-3713&lng=en
                Categories
                RESPIRATORY SYSTEM

                Respiratory medicine
                Genetics,Polymorphism, genetic,Asthma,Interleukins,Respiratory syncytial viruses,Genética,Polimorfismo genético,Asma,Interleucinas,Vírus sinciciais respiratórios

                Comments

                Comment on this article