Studies of perennial ragweed immunotherapy.

Perennial ragweed immunotherapy was studied in 24 patients with ragweed pollenosis. Cellular responsiveness was determined by measuring the cellular reactivity and sensitivity to ragweed antigen E (RW-AgE) by RW-AgE-induced leukocyte histamine release. Serum blocking antibody content was determined by measuring the serum RW-AgE binding capacity by ammonium sulfate coprecipitation of bound RW-AgE. Specific IgE (anti-RW-AgE) concentration was determined by polystyrene tube radioimmunoassay. Cellular responsiveness decreased with continuing immunotherapy, as did the specific IgE concentrations. The serum RW-AgE binding capacity, in contrast, increased as treatment continued. The absence of demonstrable correlations between RW-AgE binding capacity and cellular reactivity, cellular sensitivity, and specific IgE concentrations contrasted impressively with the demonstration of multiple significant correlations between the change in the RW-AgE binding capacity and the other parameters studied. The degree of increase in RW-AgE binding capacity correlated significantly with the degree of decrease in both the specific IgE concentration (p is less than 0.04) and the cellular sensitivity to RW-AgE (p is less than 0.003). these findings suggest that the active process of blocking antibody production, rather than the passive presence of blocking antibody, is related to the process which decreases the specific IgE concentration and the degree of cellular responsiveness and therefore results in clinical improvement.