Immunotherapy with partially purified and standardized tree pollen extracts

Patients allergic to pollen from alder, birch and hazel were hyposensitized during a 3-year period with either birch pollen extract alone (n = 24) or a mixture of one or more of alder, birch and hazel pollen extracts (n = 27). The effect of the treatment was evaluated by RAST and tandem crossed-radioimmunoelectrophoresis (tandem-CRIE). The patient' specific IgE response to the major allergens of alder (Aln g I), birch (Bet v I) and hazel (Cor a I and Cor a II), as measured by tandem-CRIE, and the total specific IgE response, measured by RAST, decreased significantly (Pc less than 0.05) during immunotherapy, irrespective of the extract used during the treatment. There was no significant difference (Pc less than 0.05) between the two treatment groups. The results obtained indicate either that birch pollen extract alone is adequate in the treatment of the studied patient group or the patients had been sensitized towards birch pollen alone.