Ascaris lumbricoides-induced interleukin-10 is not associated with atopy in schoolchildren in a rural area of the tropics

Background. In areas where intestinal helminth infections are endemic, infections by these parasites may protect against skin test-measured reactivity to allergens, and it has been suggested that interleukin (IL)-10 may mediate this effect. This study investigated whether IL-10 and populations of IL-10 ⁺ T cells may modulate atopy in children living in an area where intestinal helminth infections are endemic. Methods. Ecuadorian schoolchildren from rural communities were assessed for skin test-measured reactivity to Periplaneta americana allergen and Dermatophagoides pteronyssinus allergen. Blood samples were collected from 39 skin test-positive and 41 skin test-negative children, and peripheral-blood leukocytes were cultured in the presence of Ascaris lumbricoides antigen, to measure IL-10 protein and the frequency of T cell populations expressing intracellular IL-10. We also investigated whether these immunological factors affected the association between allergen-specific IgE and skin test-measured reactivity to aeroallergens. Results. There was no evidence of association between the level of A. lumbricoides-induced IL-10 protein or IL-10⁺ T cells and skin test-measured reactivity to allergens. The association between allergen-specific IgE and skin test-measured reactivity was not affected by the level of IL-10 protein or the frequency of IL-10⁺ T cells. Conclusions. The results of this study do not support the notion that IL-10 plays a role in modulating atopy in children living in a tropical area where intestinal helminth infections are endemic.