Asthma and indoor air: contrasts in the dose response to cat and dust-mite.
The role of the indoor environment in asthma is of major concern because (i) the disease has become more severe; (ii) we spend>or=90% of our lives indoors and (iii) a large proportion of asthmatic children and young adults are allergic to allergens found indoors. Recent evidence that children raised in a home with animals, i.e. indoor cat or dog, are less likely to become allergic has provided a great opportunity to understand the mechanisms controlling the prevalence of allergic disease. In addition the results pose a challenge to many of the hypotheses about reasons for the increase in asthma. The evidence that children or adults who make a modified TH2 response i.e. immunoglobulin (Ig)G and IgG4 ab without IgE, are not at increased risk of asthma strongly supports the role of IgE in asthma. Equally the results may give insight into a form of tolerance that could be a target for protecting patients against allergic disease.


CONCLUSIONS
Evidence for the immune response to cat allergen shows that the alternative response to an allergy, TH2 response, is a controlled or modified form of the response not a Th1 response. Furthermore, avoiding cats in the home in most communities would not decrease the prevalence of sensitization to cats because there is cat allergen distributed in schools, other public buildings, and homes without a cat.
Erwin
E A
EA
University of Virginia, Asthma and Allergic Diseases Center, Charlottesville, VA 22908-1355, USA. tap2z@virginia.edu
Custis
N
N
Ronmark
E
E
Wickens
K
K
Sporik
R
R
Woodfolk
J A
JA
Platts-Mills
T A E
TA
D016902:Air Pollution, Indoor / Q000009:adverse effects*; D000485:Allergens / Q000276:immunology*; D000818:Animals; D000829:Animals, Domestic; D001249:Asthma / Q000209:etiology* / Q000276:immunology*; D002415:Cats / Q000276:immunology; D002648:Child; D004391:Dust; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008925:Mites / Q000276:immunology; D012307:Risk Factors
D000485:Allergens; D004391:Dust; D007074:Immunoglobulin G; D007073:Immunoglobulin E