Hunt for the origin of allergy - comparing the Finnish and Russian Karelia.

The Finnish and Russian Karelia are adjacent areas in northern Europe, socio-economically distinct but geoclimatically similar. The Karelia Allergy Study was commenced in 1998 to characterize the allergy profiles in the two areas. Allergy prevalence had increased in Finland since the early 1960s, but the situation in Russia was unknown. The key finding was that allergic symptoms and diseases were systematically more common in Finnish children and adults than in their Russian counterparts. For example, in the early 2000s, hay fever in school children was almost non-existent in Russian Karelia, and only 2% were sensitized to birch pollen compared with 27% in Finnish Karelia. Adult birth cohorts showed that among those born in the 1940s, the sensitization to pollens and pets was at the same low level in both countries, but among younger generation born in the late 1970s, the difference was already manifold. Seropositivity to some pathogens, microbial content in house dust and drinking water seemed to confer allergy protection in Russia. In subsequent studies, it became apparent that on the Finnish side, healthy children had a more biodiverse living environment as well as greater diversity of certain bacterial classes on their skin than atopic children. Abundance of skin commensals, especially Acinetobacter (gammaproteobacteria), associated with anti-inflammatory gene expression in blood leucocytes. In vivo experiments with the mouse model demonstrated that intradermally applied Acinetobacter protected against atopic sensitization and lung inflammation. These observations support the notion that the epidemic of allergy and asthma results from reduced exposure to natural environments with rich microbiota, changed diet and sedentary lifestyle. Genetic studies have confirmed strong influence of lifestyle and environment. With our results from the Karelia study, a 10-year National Allergy Programme was started in 2008 to combat the epidemic in Finland.

A disparity in the association of asthma, rhinitis, and eczema with allergen-specific IgE between Finnish and Russian Karelia.

BACKGROUND: A substantial variation in the association of asthma, rhinitis and eczema with elevated serum allergen-specific immunoglobulin E (sIgE) levels between different populations has been reported. Here, we wanted to clarify whether these proportions are different in Finnish and Russian Karelia, and compared the ability of questionnaires, skin prick tests (SPT) and sIgE measurements to detect atopic conditions in these adjacent areas with different living conditions. METHODS: Randomly selected schoolchildren, aged 6-16 years, and their mothers from Finland (n = 344 children, 344 mothers) and Russia (427 and 284 respectively) participated. SPTs and sIgE measurements to common inhalant and food allergens were performed. The occurrence of asthma, rhinitis, eczema and related symptoms was assessed with an International Study of Asthma and Allergies in Childhood-based questionnaire. Correlation between SPT and sIgE was estimated using the Spearman correlation coefficient. RESULTS: The rate of positive sIgE results was significantly higher in Finland among both mothers and children. Seventy-seven per cent of Finnish children and 43% of Russian children with asthma were sIgE positive. The respective figures for hay fever were 94% and 67%, and for eczema 68% and 41%. This discrepancy was similar but of lower magnitude among mothers. The overall occurrence of asthma, rhinitis and eczema was very low in Russian Karelia. The correlation between SPT and sIgE results was generally good. CONCLUSION: Asthma, rhinitis and eczema in Russian Karelia are not only rare but also, to a large extent, have no sIgE component. Therefore, the ability of questionnaires to detect sIgE-mediated atopic conditions in this area of Russia is poor.