title: Allergy and cancer.
abstract: BACKGROUND
  Conflicting results have provided support for two distinct and contradictory hypotheses: (i) allergy has a protective effect against cancer by enhanced immune surveillance, and (ii) allergy is associated with an increased risk of cancer by chronic immune stimulation. We therefore aimed us to perform a large epidemiological study with a defined allergic disease cohort.
  
  
  METHODS
  During the years 1988-2000, 70 136 patients tested for total serum immunoglobulin E (IgE) and 57 815 tested with Phadiatop for diagnosing allergic disease at Karolinska University Hospital, Stockholm, Sweden, were linked with the Swedish Cancer Registry for a virtually complete follow up with regard to cancer.
  
  
  RESULTS
  The total number of observed cancers was normal in the total serum IgE-cohort; standardized incidence ratio (SIR) = 0.98 (95% CI: 0.92-1.04) and in the Phadiatop-cohort: SIR = 0.99 (0.92-1.06) independent of the level of IgE and positive or negative Phadiatop. Specific analysis was done for cancer of the lung, cervix, pancreas, lymphoma, and nonmelanoma skin cancer. None of these forms of cancer had increased risks.
  
  
  CONCLUSIONS
  The study does not support the hypothesis that allergy has a protective effect against cancer, nor does it support an increased risk.
authors.affiliation: Unit of Dermatology and Venereology, Karolinska University Hospital and Institute, Stockholm, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Lindelöf
authors.forename: F
authors.initials: F
authors.lastname: Granath
authors.forename: M
authors.initials: M
authors.lastname: Tengvall-Linder
authors.forename: A
authors.initials: A
authors.lastname: Ekbom
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016021:Epidemiologic Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006967:Hypersensitivity / Q000150:complications / Q000276:immunology*; D007108:Immune Tolerance / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications / Q000276:immunology*; D013548:Sweden
chemical_list: D007073:Immunoglobulin E