Elevated Concentrations of Salivary Secretory Immunoglobulin A Anti-Cow’s Milk Protein in Newborns at Risk of Allergy

Abstract

Secretory immunoglobulin A (SIgA) anti-casein and SIgA anti-β-lactoglobulin (BLG) were determined in the saliva of 158 healthy mature infants at birth and in breast milk samples using a direct Elisa technique. IgG anti-casein and anti-BLG were measured in serum samples from mothers and newborns (cord blood). A high risk of allergy was defined in 66 infants who had cord blood (CB)-IgE levels ≥0.9 IU/ml and/or parents with atopic diseases. Thirty infants had CB levels <0.9 IU/ml and parents without clinical symptoms of atopy but with elevated serum IgE concentrations or type I skin reactions to common allergens (low risk). Sixty-two infants had CB-IgE levels <0.9 IU/ml and healthy parents (no risk). The groups were matched for social status, smoking and dietary habits. SIgA anti-casein and anti-BLG were detected in all newborns. SIgA anti-casein was significantly higher (p <0.05) in high risk infants (median 157; 50% confidence limits 45–270) than in no risk (48; 25–150) or low risk infants (43; 21–130). SIgA anti-casein values correlated with maternal allergy, maternal allergy plus CB-IgE, but not with paternal allergy. Breast milk SIgA anti-BLG was depressed (p <0.05) in mothers with manifest allergy compared to healthy mothers. Determination of salivary SIgA anti-casein may represent an additional screening method for early detection of infants with atopic disposition.