PT  - JOURNAL ARTICLE
AU  - Juha Pekkanen
AU  - Mikko Lappalainen
AU  - Anne Hyvärinen
AU  - Helena Rintala
AU  - Harald Renz
AU  - Petra Pfefferle
AU  - Aino Nevalainen
AU  - Marjut Roponen
AU  - Maija-Riitta Hirvonen
TI  - High indoor microbial levels are associated with reduced Th1-cytokine secretion capacity in infancy
DP  - 2011 Sep 01
TA  - European Respiratory Journal
PG  - 1728
VI  - 38
IP  - Suppl 55
4099  - http://erj.ersjournals.com/content/38/Suppl_55/1728.short
4100  - http://erj.ersjournals.com/content/38/Suppl_55/1728.full
SO  - Eur Respir J2011 Sep 01; 38
AB  - Background: In the early stages of life exposure to microbes and their components may affect the maturation and functions of immune system.Objective: To examine whether the house dust microbial content is associated with cytokine -producing capacity at birth and at age 1 year.Methods: Production of TNF-α, IFN-γ, IL-5, IL-8 and IL-10 at birth (n=228) and at age 1 year (n=200) following 24h and 48h whole blood stimulation with Staphylococcal enterotoxin B (SEB), lipopolysaccharide and phorbol ester/ionomycin were measured using ELISA. Ergosterol (marker for fungal biomass), muramic acid (marker for Gram-positive bacteria) and 3-hydroxy fatty acids (C10:0-C14:0, marker for Gram-negative bacteria) were analyzed from floor dust. Five single microbial species or groups were determined using quantitative polymerase chain reaction method.Results: A high total level of Gram-positive bacteria in general or Mycobacterium spp. in house dust was associated with decreased SEB-stimulated IFN-γ production, especially at age 1 year. Total level of analyzed indoor fungi (PenAsp group, Trichoderma viride group, Wallemia sebi) was also inversely associated with IFN-γ production at age 1 year, but this association lost significance after multivariate adjustment. Only few associations were found between microbial exposures and other measured cytokines.Conclusions: High indoor microbial exposures may affect immune development in early life by reducing Th1 –cytokine secretion capacity. In the future, more attention should be paid especially to the immunomodulatory role of Gram-positive bacterial exposures.