Quantity and avidity of antibodies against birch pollen in atopic patients during hyposensitization. A preliminary...

The degree and strength of the binding of radioactively labelled allergen by antibodies in the sera of birch pollen-sensitive individuals was studied during the course of hyposensitization with alun-precipitated aqueous-pyridine extracted birch pollen antigens using the ammonium-sulphate precipitation technique originally described by FARR. The allergen binding was measured before and after absorption of the sera with anti-human IgE antibodies conjugated to Sepharose. It was noted that IgE antibodies of low avidity caused clinical sensitivity as well as IgE antibodies of higher avidity. The nasal sensitivity to birch pollen allergen of six of the seven patients studied significantly decreased by the treatment without any quite uniform change of serum-binding capacity for the allergen. Thus the clinical improvement was accompanied either by disappearance of the specific IgE antibodies, concomitant with formation of antigen-binding non-IgE antibodies, or by increased formation of IgE antibodies with very slight contribution by non-IgE antibodies to the totally increased antigen-binding efficiency. It is felt that the serological antibody changes may not reflect the most relevant immunological events during successful hyposensitization therapy.