The hygiene hypothesis suggests that a lifestyle with better health and sterilized facilities in Western countries decreases the chances of exposure to microbial substances, virulent substances and allergens during 'childhood. A study conducted to study two groups of people from different countries but of genetically related European races. 266 Finnish and 266 Karelian children with allergen-specific IgE were recruited and sampled. The results of the study show however that Karelian children have twice as much IgE as Finnish children, but the IgE of Finnish children shows a significantly high amount of IgE to specific allergens. The prevalence of antibodies against microbes is also significantly higher in Karelian children. The high prevalence of microbial antibodies reflects poor environmental hygiene and the high rate of pathogenic infections in Karelia, so more antibodies are produced to isolate harmful microbes and chemicals. The low level of IgE to the specific allergen in Karelian children reflects the low prevalence of allergic sensitizers. The author assumes that children in Finland are exposed to the infection at a lower rate and at an older age. The hygiene hypothesis also explained that infections occurring during childhood promote the maturation of the immune system, the development of the balance of TH1 and TH2 lymphocytes (Seiskari T et al,