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Respiratory atopic disease, Ascaris-immunoglobulin E and tuberculin testing in urban South African children.
Respiratory atopic disease, Ascaris-immunoglobulin E and tuberculin testing in urban South African children.
Obihara, C.C. Buyers, N. Gie, R.P. Hoekstra, M.O. Fincham, J.E. Marais, B.J. Lombard, C.J. Dini, L.A. Kimpen, J.L.L.
Obihara, C.C.
Buyers, N.
Gie, R.P.
Hoekstra, M.O.
Fincham, J.E.
Marais, B.J.
Lombard, C.J.
Dini, L.A.
Kimpen, J.L.L.
Abstract
Background Epidemiological relation of intestinal helminth infection and atopic disease, both associated with a T‐helper (Th) 2 immune response, is controversial, as it has been reported that helminth infection may either suppress or pre‐dispose to atopic disease. This relation has not been tested in an area with a high burden of Mycobacterium tuberculosis (MTB) infection, a known Th1‐stimulating infection.
Objective To study the association of intestinal helminth infection and atopic disease in a community where helminth infection is endemic and MTB infection is high.
Methods Three‐hundred and fifty‐nine randomly selected children aged 6–14 years from a poor urban suburb were tested with allergy questionnaire, skin prick test (SPT) to common aeroallergens, Ascaris‐specific IgE (Ascaris‐sIgE), fecal examination for pathogenic intestinal helminths and tuberculin skin testing (TST). Histamine bronchoprovocation was tested in the group of children aged 10 years and older. Results were corrected for demographic variables, socioeconomic status, parental allergy, environmental tobacco smoke (ETS) exposure in the household, recent anthelminthic treatment and for clustering in the sampling unit.
Results Ascaris‐sIgE was elevated in 48% of children, Ascaris eggs were found in 15% and TST was positive in 53%. Children with elevated Ascaris‐sIgE had significantly increased risk of positive SPT to aeroallergens, particularly house dust mite, atopic asthma (ever and recent), atopic rhinitis (ever and recent) and increased atopy‐related bronchial hyper‐responsiveness. In children with negative TST (<10 mm), elevated Ascaris‐sIgE was associated with significantly increased risk of atopic symptoms (adjusted odds ratio (ORadj) 6.5; 95% confidence interval (CI) 1.9–22.4), whereas in those with positive TST (10 mm) this association disappeared (ORadj 0.96; 95% CI 0.4–2.8).
Conclusions These results suggest that immune response to Ascaris (Ascaris‐sIgE) may be a risk factor of atopic disease in populations exposed to mild Ascaris infection and that MTB infection may be protective against this risk, probably by stimulation of anti‐inflammatory networks.
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Date
2006-05
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Blackwell
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Keywords
Dermatology , Immunology, immunopathology, allergology , Pneumology , Biological and medical sciences , Immunologie fondamentale , Fundamental and applied biological sciences. Psychology , Medical sciences , Immunopathology , Allergic diseases , Exploration , Human , Immunology , Immunopathology , Allergy , Respiratory disease , Atopy , Medical screening , Child , Urban environment , Skin test , Tuberculin , atopic disease , childhood , tuberculin skin test.
Citation
Obihara CC, Beyers N, Gie RP, Hoekstra MO, Fincham JE, Marais BJ, et al. Respiratory atopic disease, Ascaris-immunoglobulin E and tuberculin testing in urban South African children. Clinical And Experimental Allergy: Journal Of The British Society For Allergy And Clinical Immunology [Internet]. 2006 May;36(5):640–8