Immunoglobulins in nasal secretions of infants.

A new method was used to measure immunoglobulin and total protein concentrations in nasal secretions of normal infants and infants with acute respiratory infections and with allergies. A measured quantity of inulin was added to the administered wash solution in order to determine the dilution of the nasal secretions washed from the infants. In normal infants IgA concentration was less than IgG concentration. In nasal secretions from infants with acute respiratory infections IgA concentration was higher and IgG concentration was lower than in secretions from normal infants. Nasal secretions were studied without the inulin marker in a larger group of normal infants and in infants with acute respiratory infections, a family history of asthma, atopic dermatitis, or asthma. Only relative concentrations of immunoglobulins and total protein can be determined from these studies. There was no difference between the group with a family history of asthma and the control group. IgA/IgG and IgG/TP ratios in asthmatics were not significantly different from those in normal subjects. IgG/TP was significantly lower in asthmatics than in normal infants. Infants with atopic dermatitis had a lower IgA/IgG ratio in their secretions than normal nonallergic controls. The possible implications of these findings to the development of the immune system and the pathogenesis of disease are discussed.