Levels of immunoglobulin G, M, A, and E at various ages in allergic and nonallergic black and white individuals.

Studies were conducted to detect major differences in immunoglobulin levels between allergic and nonallergic individuals. Immunoglobulins G, M, A, and E were quantitated in members of 63 families selected for the presence of children with asthma or allergic rhinitis and compared with a larger group of healthy individuals and families. Mean IgE levels were significantly higher in healthy black than in white individuals. No significant difference was found in IgE levels between healthy parents with and without allergic children. Mean IgE levels were significantly higher in asthmatic children than in healthy children and also much higher in asthmatic children than in their healthy siblings. Asthma occurred more frequently in boys than in girls. IgE levels in healthy children increased rapidly early in childhood, reached a peak before 10 yr of age, and decreased during the teens. This decrease in IgE during the teens may provide the immunologic mechanism by which some children can "outgrow" certain childhood allergies. IgA levels were very low in young children and not significantly different between allergic and healthy individuals. The low IgA level in young children may be of importance in the development of childhood allergies.