International variations in associations of allergic markers and diseases in children: ISAAC Phase Two.
Allergy
; 65(6): 766-75, 2010 Jun 01.
Article
in En
| MEDLINE
| ID: mdl-20028376
ABSTRACT
BACKGROUND:
Circulating allergen-specific IgE (sIgE) and skin prick tests (SPT) are used to define atopy. Downregulation of local inflammatory responsiveness has been proposed to explain a low prevalence of positive SPTs in less affluent countries. We analysed the association between SPTs, total and allergen-specific IgE and their relationships to allergic symptoms in centres with diverse living conditions.METHODS:
Cross-sectional studies of stratified random samples of 8 to 12-year-old children (n = 7461) used the standardized methodology of Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema were ascertained by parental questionnaires. Skin examination, hypertonic saline bronchial challenge, six aeroallergen SPTs and measurements of serum total IgE and sIgE were performed.RESULTS:
In nonaffluent countries, a higher proportion of children with positive SPT had no detectable sIgE (range 37-61%) than in affluent countries (0-37%). Total serum IgE was associated with all disease outcomes among children with both positive SPT and sIgE (P < 0.001), but only with self-reported eczema in children with negative SPTs and negative sIgE.CONCLUSIONS:
The international pattern of discordance between SPT and sIgE results did not support the downregulation hypothesis. Among children with no evidence of sensitization to common aeroallergens, increased total IgE contributes little to the risk of wheeze and rhinitis in the general population but may play a role in eczema.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Immunoglobulin E
/
Skin Tests
/
Hypersensitivity
Type of study:
Clinical_trials
/
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Limits:
Child
/
Humans
Language:
En
Journal:
Allergy
Year:
2010
Document type:
Article
Affiliation country: