Serum IgE levels and allergic spectra in immigrants to Sweden

We evaluated the allergy status of 134 immigrants from Asia, Africa, the Middle East and South America, who were referred to our clinic during the past 10 years. Fifty Swedish patients were used for comparison. When the atopy state was not taken into account, no significant difference was found between the two groups with respect to total IgE levels. However, IgE levels of non-atopic immigrants were significantly higher than the IgE levels of non-atopic Swedes. While there was no significant difference in IgE levels between atopic and non-atopic immigrants, this difference was significant in Swedish patients. In general, IgE levels of immigrants showed a decline with time and reached approximately the same levels as for the Swedish patients in 10.5 years. In the immigrant group atopic women had a considerably lower IgE level than the atopic men. Among the atopics there were no differences between sexes. In Swedes and immigrants pollen was the most common group of allergens. The spectrum of allergy in the immigrant group changed with time in Sweden, and gradually became more similar to the Swedish spectrum. Skin and/or RAST positivity to birch increased from 16% within 2.5 years to 53% after more than 10.5 years in Sweden. Our data indicate that environmental factors rather than hereditary differences determine the IgE state. Within a few years the immunologic status of immigrants adapts to the new environment.