Determination of specific IgE and IgG serum antibodies during immunotherapy in hay fever patients by RAST.

A solid phase radio-immunoassay, based on the commercially available antigen preparations on paper discs supplied with the radio-allergosorbent test (Phadebas RAST, Pharmacia) for semi-quantitative determination of specific IgE has been applied to the demonstration of allergen-specific antibodies of the IgG class in sera of hay fever patients. A significant rise of specific IgG antibody has been observed regularly as a result of successful immunotherapy. The rise of such "blocking antibodies" occurred within 3 months after commencement of immunotherapy (IT), well before nasal provocation tests became negative in the patients. No significant decrease of specific IgE antibodies was observed over the one year observation period. While these data confirm earlier results by other groups concerning the appearance of blocking antibodies of IgG class as a result of IT, thus providing additional evidence for its mechanism, they also offer a convenient serological method for monitoring the results of IT.