title: The IgE response to Ascaris molecular components is associated with clinical indicators of asthma severity.
abstract: BACKGROUND
  Asthma is a common chronic disease worldwide and Ascaris lumbricoides infection (ascariasis) is frequent in tropical regions. However, the effect of ascariasis on asthma severity has not been sufficiently explored. We sought to evaluate the influence of the IgE immune response to Ascaris extract and purified house dust mites (HDM) and Ascaris allergens on indicators of asthma severity in patients living in the tropics.
  
  
  METHODS
  Asthmatic patients from Cartagena, Colombia were recruited. Clinical assessment included questionnaires, physical examination, allergy skin tests, spirometry, parasite stool examination and IgE antibody measurements. Asthma was diagnosed by a physician according to validated criteria. Indicators of severity were occurrence of severe dyspnea episodes, night awakenings events, > 4 emergency room (ER) visits and hospitalizations during the last year. Specific IgE to Der p 2, Ascaris spp., Blomia tropicalis and Dermatophagoides pteronyssinus extracts was determined by ImmunoCap. IgE to tropomyosins (Asc l 3, Blo t 10 and Der p 10), Blo t 5 and Asc s 1 was detected by ELISA. Logistic regression analyses were used to explore the relationships between sensitization and indicators of asthma severity.
  
  
  RESULTS
  After adjustment for HDM sensitization, Ascaris sensitization remained associated with severe dyspnea (aOR: 1.90, 95% CI: 1.08 - 3.34, p = 0.03) and > 4 ER visits (aOR: 2.23, 95% CI: 1.15 - 4.30, p = 0.02). We also found that sensitization to the species specific markers Blo t 5 and Asc s 1, as well as the cross-reactive tropomyosins of D. pteronyssinus and Ascaris were associated with > 4 ER visits. Der p 2 sensitization was associated with bronchodilator responsiveness (aOR: 2.24: 1.25-4.02, p = 0.01). Remarkably, significantly higher IgE levels to HDM species specific allergens were found in Ascaris sensitized patients.
  
  
  CONCLUSIONS
  In this tropical population, IgE sensitization to Ascaris and the cross-reactive tropomyosins was frequent and associated with clinical indicators of asthma severity. The significant relationship between sensitization to the nematode-specific marker Asc s 1 and ER attendance supports these findings. Moreover, ascariasis increases the human IgE responses to HDM specific allergens.
authors.affiliation: Institute for Immunological Research, University of Cartagena, Cartagena, Colombia.
authors.forename: Emiro
authors.initials: E
authors.lastname: Buendía
authors.affiliation: Institute for Immunological Research, University of Cartagena, Cartagena, Colombia ; Foundation for the Development of Medical and Biological Sciences (Fundemeb), Cartagena, Colombia.
authors.forename: Josefina
authors.initials: J
authors.lastname: Zakzuk
authors.affiliation: Institute for Immunological Research, University of Cartagena, Cartagena, Colombia.
authors.forename: Dilia
authors.initials: D
authors.lastname: Mercado
authors.affiliation: Department of Microbiology, Faculty of Medicine, University of Cartagena, Cartagena, Colombia.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alvarez
authors.affiliation: Institute for Immunological Research, University of Cartagena, Cartagena, Colombia ; Foundation for the Development of Medical and Biological Sciences (Fundemeb), Cartagena, Colombia.
authors.forename: Luis
authors.initials: L
authors.lastname: Caraballo
keywords: Ascariasis; Ascaris; Asthma severity; Atopy; Blomia tropicalis; Dermatophagoides pteronyssinus; House dust mites; IgE; Lung function; Poverty; The tropics; Urban