Antibody response following immunotherapy in ragweed hay fever: Allpyral vs. whole ragweed extract

The antigenicity of commercially available ragweed pollen extracted with pyridine and precipitated with alum (Allpyral) was compared with that of aqueous ragweed extract. The antibody response was measured by the inhibition of histamine release from sensitive human leukocytes challenged with either ragweed antigen E or whole aqueous extract. A group of patients treated with aqueous extract had a significantly greater antibody response than a similar group treated with Allpyral, even though the latter received 30 times as much antigen. Another comparison showed that patients who had received high dosage Allpyral therapy (average: 0.80 mg. of protein N. or 80,000 PNU) had antibody levels which did not differ significantly from those of untreated control patients.