Mold-specific immunoglobulin G antibodies in a child population

The determination of immunoglobulin G (IgG) antibodies to molds has been used as an objective evidence of significant mold exposure. Until present, no data have been published on antibody responses to molds in healthy children living in normal housing conditions. The microbe-specific IgG antibody concentrations of 21 molds and 3 actinobacteria were determined by enzyme-linked immunosorbent assay (ELISA) in 103 1- to 6-year-old children (12.4% of the population of that age), and in 111 7- to 14-year-old school children (12.1%). The international standard sera were available, and the IgG concentrations of the test sera could be expressed in mg/l. On average, IgG concentrations increased in relation to age until the age of 6–7 years. At school age the increase still continued but more slowly. Actinobacteria were the only exceptions; all three tested strains Sreptomyces albus, S. griseus and S. halstedii resulted in rather high concentrations until 3 years of age. If the children lived in a farm, mold-specific IgG concentrations increased at an earlier age than in other children. The results between farmers' children and other children differed significantly before school age for 20 of the 24 microbes tested, the four exceptions being the 3 actinobacteria and the mold Aspergillus versicolor. The reference values must be age related, and separate references are needed for farmers' children before school age.