Early infection with Trichuris trichiura and allergen skin test reactivity in later childhood.
BACKGROUND
Allergic diseases cause a large and increasing burden in developed countries and in urban centres in middle-income countries. The causes of this increase are unknown and, currently, there are no interventions to prevent the development of allergic diseases. The 'hygiene hypothesis' has tried to explain the increase through a reduction in the frequency of childhood infections causing a failure to program the immune system for adequate immune regulation. Intestinal helminth parasites are prevalent in childhood in developing countries and are associated with a lower prevalence of allergen skin test reactivity and asthma.


OBJECTIVE
To investigate whether children who had intestinal helminth infections during early childhood have a lower prevalence of allergen skin test reactivity later in childhood.


METHODS
We re-visited a population of 1055 children from whom stool samples had been collected for detection of intestinal helminth infections for another study, and collected new stool samples and performed allergen skin prick testing. Information on potential confounding variables was collected.


RESULTS
Children with heavy infections with Trichuris trichiura in early childhood had a significantly reduced prevalence of allergen skin test reactivity in later childhood, even in the absence of T. trichiura infection at the time of skin testing in later childhood.


CONCLUSIONS
Early heavy infections with T. trichiura may protect against the development of allergen skin test reactivity in later childhood. Novel treatments to program immune-regulation in early childhood in a way that mimics the effects of early infections with T. trichiura may offer new strategies for the prevention of allergic disease.
London School of Hygiene and Tropical Medicine, London, UK. laura.rodrigues@ishtm.ac.uk
L C
LC
Rodrigues
P J
PJ
Newcombe
S S
SS
Cunha
N M
NM
Alcantara-Neves
B
B
Genser
A A
AA
Cruz
S M
SM
Simoes
R
R
Fiaccone
L
L
Amorim
P J
PJ
Cooper
M L
ML
Barreto
D000485:Allergens / Q000276:immunology*; D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D001196:Ascariasis / Q000453:epidemiology / Q000276:immunology; D017164:Ascaris lumbricoides / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D005243:Feces / Q000469:parasitology; D005260:Female; D006373:Helminthiasis / Q000453:epidemiology / Q000276:immunology; D006725:Hookworm Infections / Q000453:epidemiology / Q000276:immunology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D007223:Infant; D007411:Intestinal Diseases, Parasitic / Q000453:epidemiology / Q000276:immunology; D008297:Male; D016017:Odds Ratio; D012882:Skin Tests; D014257:Trichuriasis / Q000453:epidemiology / Q000276:immunology*; D014258:Trichuris / Q000276:immunology* / Q000302:isolation & purification
D000485:Allergens; D000947:Antigens, Helminth