title: Inverse association between skin response to aeroallergens and Schistosoma mansoni infection.
abstract: BACKGROUND
  Helminthic infections and allergic disease are highly prevalent in many areas of the world. It is known that IgE antibodies are involved in the pathogenesis of both helminthiasis and atopy. However, the consequences of the presence of helminthic infections in atopic patients are still not completely understood.
  
  
  METHODS
  Subjects infected by Schistosoma mansoni with more than 200 eggs/g of feces (n = 42) and uninfected subjects (n = 133) were selected from an endemic area of schistosomiasis. The history of allergy and results of the immediate hypersensitivity prick tests with inhalant allergen extracts were registered. Total IgE and IgE specific to S. mansoni and aeroallergens were measured in serum by ELISA.
  
  
  RESULTS
  The proportion of individuals with a positive skin test to allergens was higher in the uninfected group (24.3%) than in the group with more than 200 eggs/g of feces (4.8%). The odds of atopy (defined as a positive test for at least one of the antigens) were 5 times higher (odds ratio = 7.0; 95% confidence interval = 1.6-31.1%; p = 0.01) in the uninfected group, after taking into account the potential influence of gender and age. While there was a tendency for higher total and S. mansoni-specific IgE levels in infected patients, an opposite trend, that is higher aeroallergen-specific IgE, was observed in uninfected subjects.
  
  
  CONCLUSIONS
  There was a strong and statistically significant inverse association between the immediate skin test response to common aeroallergens and infection by S. mansoni. The results indicate that immediate hypersensitivity reactions may be suppressed in S. mansoni-infected individuals.
authors.affiliation: Serviço de Imunologia do Hospital Universitário Prof. Edgard Santos, Universidade Federal da Bahia, Salvador, Brasil.
authors.forename: M I
authors.initials: MI
authors.lastname: Araujo
authors.forename: A A
authors.initials: AA
authors.lastname: Lopes
authors.forename: M
authors.initials: M
authors.lastname: Medeiros
authors.forename: A A
authors.initials: AA
authors.lastname: Cruz
authors.forename: L
authors.initials: L
authors.lastname: Sousa-Atta
authors.forename: D
authors.initials: D
authors.lastname: Solé
authors.forename: E M
authors.initials: EM
authors.lastname: Carvalho
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000485:Allergens / Q000276:immunology*; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D019570:Inhalation Exposure; D008297:Male; D016017:Odds Ratio; D012550:Schistosoma mansoni / Q000276:immunology; D012555:Schistosomiasis mansoni / Q000097:blood / Q000276:immunology*; D012737:Sex Factors; D012882:Skin Tests
chemical_list: D000485:Allergens; D000909:Antibodies, Helminth; D007073:Immunoglobulin E