Allergic sensitization and microbial load − a comparison between Finland and Russian Karelia

Authors

  • T. Seiskari,

    Corresponding author
    1. Department of Virology, University of Tampere, Finland,
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  • A. Kondrashova,

    1. Department of Virology, University of Tampere, Finland,
    2. JDRF Centre for Prevention of Type 1 Diabetes in Finland,
    3. Department of Paediatrics, University of Petrozavodsk, Russia,
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  • H. Viskari,

    1. Department of Virology, University of Tampere, Finland,
    2. JDRF Centre for Prevention of Type 1 Diabetes in Finland,
    3. Department of Clinical Microbiology, Centre for Laboratory Medicine, Pirkanmaa Hospital District, Tampere, Finland,
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  • M. Kaila,

    1. Centre for General Practice, Pirkanmaa Hospital District, Tampere, Finland,
    2. Paediatric Research Centre University of Tampere, Finland,
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  • A.-M. Haapala,

    1. Department of Clinical Microbiology, Centre for Laboratory Medicine, Pirkanmaa Hospital District, Tampere, Finland,
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  • J. Aittoniemi,

    1. Department of Clinical Microbiology, Centre for Laboratory Medicine, Pirkanmaa Hospital District, Tampere, Finland,
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  • M. Virta,

    1. Department of Microbiology and Immunology, University of Tampere, Finland,
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  • M. Hurme,

    1. Department of Clinical Microbiology, Centre for Laboratory Medicine, Pirkanmaa Hospital District, Tampere, Finland,
    2. Department of Microbiology and Immunology, University of Tampere, Finland,
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  • R. Uibo,

    1. Department of Immunology, University of Tartu, Estonia,
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  • M. Knip,

    1. JDRF Centre for Prevention of Type 1 Diabetes in Finland,
    2. Hospital for Children and Adolescents, University of Helsinki, Finland, and
    3. Department of Paediatrics, Tampere University Hospital, Finland
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  • H. Hyöty,

    1. Department of Virology, University of Tampere, Finland,
    2. JDRF Centre for Prevention of Type 1 Diabetes in Finland,
    3. Department of Clinical Microbiology, Centre for Laboratory Medicine, Pirkanmaa Hospital District, Tampere, Finland,
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  • The EPIVIR study group

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      For the list of EPIVIR Study Group contributors, please see the list at the end of the paper.


Tapio Seiskari, Department of Virology, University of Tampere, Biokatu 10, 33520 Tampere, Finland.
E-mail: tapio.seiskari@uta.fi

Summary

Epidemiological data have indicated that some infections are associated with a low risk of allergic diseases, thus supporting the idea (hygiene hypothesis) that the microbial load is an important environmental factor conferring protection against the development of allergies. We set out to test the hygiene hypothesis in a unique epidemiological setting in two socio-economically and culturally markedly different, although genetically related, populations living in geographically adjacent areas. The study cohorts included 266 schoolchildren from the Karelian Republic in Russia and 266 schoolchildren from Finland. The levels of total IgE and allergen-specific IgE for birch, cat and egg albumen were measured. Microbial antibodies were analysed against enteroviruses (coxsackievirus B4), hepatitis A virus, Helicobacter pylori and Toxoplasma gondii. Although total IgE level was higher in Russian Karelian children compared to their Finnish peers, the prevalence of allergen-specific IgE was lower among Russian Karelian children. The prevalence of microbial antibodies was, in turn, significantly more frequent in the Karelian children, reflecting the conspicuous difference in socio-economic background factors. Microbial infections were associated with lower risk of allergic sensitization in Russian Karelian children, enterovirus showing the strongest protective effect in a multivariate model. The present findings support the idea that exposure to certain infections, particularly in childhood, may protect from the development of atopy. Enterovirus infections represent a new candidate to the list of markers of such a protective environment. However, possible causal relationship needs to be confirmed in further studies.

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