Ninety-five children with pollen hay fever were treated for 46 months (16-74 months) with extracts of birch pollen (seventy-two children) and/or grass pollen (fifty-nine children).
During the first 2 months of this immunotherapy the serum concentration of allergen-specific IgE antibodies doubled or tripled, but the concentration of IgG‘blocking’antibodies increased even more.
With time the IgE antibody activity decreased in 80% of the children, but only in slightly more than 50% did it fall to below the initial level, and the mean concentration at the end of the study was 2-3 times the initial value. The IgG antibody activity remained high in about 50% of the children and showed a tendency to decrease in the other children, in spite of monthly allergen injections.
Eighty-three out of the ninety-five children reported a moderate to marked improvement. At the end of the study the eighteen almost symptom-free children had a higher IgG/IgE antibody ratio than the twelve children who had not improved, but this difference was not significant.
After treatment, thirteen children tolerated ten to 10,000 times more allergen than before by naso-conjunctival challenge tests. Ten of the children reacted to the same allergen dilution as before and two reacted to a ten times weaker extract. Clinical improvement was accompanied by increased tolerance in most patients.