Effects of allergy, intestinal helminthic infestation and sex on serum IgE concentrations and immediate skin hypersensitivity in three ethnic groups.

Serum IgE concentrations were measured in 232 blood donors resident in the Western Cape, South Africa. Subjects were interviewed for histories of allergy and skin tested with a variety of common allergens. Faecal specimens were collected for microscopic examination. Results confirmed that Cape Coloureds and Africans tend to have elevated serum IgE concentrations and showed that African males have a high prevalence of immediate skin hypersensitivity. Cape Coloureds and Africans had high prevalences of helminthic infestation and relatively low prevalence of allergic symptoms. Only in Whites were elevated serum IgE concentrations associated with positive allergic histories; in this group, results suggested that the sex difference in serum IgE concentrations observed previously is owing to differences in the IgE responses of allergic males and females.