Specific IgE and IgG antibody responses in children to timothy pollen components during immunotherapy.

Fourteen children with timothy grass pollinosis were given immunotherapy (IT) for 3 years with a purified and characterized timothy grass pollen preparation or a crude aqueous timothy pollen extract. Crossed radioimmunoelectrophoresis (CRIE) showed that 75% of the children under 11 years of age developed new specificities of IgE antibodies against timothy antigens, in contrast to older children, where no development of IgE antibodies against new timothy antigens could be detected. IgE antibodies were only detected against antigens formerly known as allergens. Timothy-specific IgG antibodies increased in most children during hyposensitization against the major allergens Ag 19 and Ag 24/25 and several other IgE-binding timothy antigens.