Eighteen adult patients with allergic rhinitis due to Timothy pollen were observed for 36 weeks before, during and after the grass pollen season. Eight patients were treated by parenteral hyposensitization with grass pollen extract, and ten patients who were given no immunotherapy served as controls. Timothy-specific IgE, IgG and IgA antibodies in samples of serum and nasal secretion were quantified by radioimmunological technique.
In comparison with the control group, the serum concentration of Timothy-specific IgE antibodies increased significantly (P <0.05) during the preseasonal hyposensitization treatment and then decreased significantly (P <0.05) during and after the pollen season while this therapy was being continued. In the hyposensitized patients the serum concentration of both IgG and IgA antibodies increased highly significantly (P <0.01 and P <0.001, respectively) during immunotherapy.
In nasal secretion quantitative changes of the three types of antibodies were usually less pronounced or not detectable at all. The concentration of IgG antibodies, however, showed some increase in the nasal secretion during hyposensitization. These minor increases in allergen-specific IgG and IgA antibodies in nasal secretion might explain why parenteral hyposensitization in allergic rhinitis often does not give complete relief from symptoms.