Genetic influence on the serum levels of naturally occurring human IgG antibodies to dietary antigens. Quantitative assessment from a twin study.

Serum IgG antibodies to ovalbumin (OA) and beta-lactoglobulin (BLG) were quantified by ELISA techniques in 22 monozygotic (MZ) and 24 dizygotic (DZ) healthy twin pairs. Antibody levels were comparable in the MZ and DZ groups both for anti-OA and anti-BLG antibodies. The genetic variance (GWT) was 0.167 for log IgG anti-OA antibodies, and 0.173 for log IgG anti-BLG antibodies, with heritability estimates of 0.44 and 0.37, respectively. No indication was observed of genotype-environmental interaction or differential environmental covariance for the log antibody levels in the MZ and DZ twins. The anti-OA and anti-BLG antibody levels in the same individual correlated only to a low degree. The levels of naturally occurring serum IgG antibodies are significantly influenced by genetic factors.