A multi-institutional trial of polymerized whole ragweed for immunotherapy of ragweed allergy

Eighty ragweed-sensitive patients in four cities were recruited to study the safety and efficacy of partially purified, polymerized whole ragweed (PRW) as an improved form of immunotherapy. Groups of 20 patients in Chicago, Boston, Memphis, and St. Louis had blood drawn for immunologic studies before and after the 1978 and 1979 ragweed seasons and completed detailed daily symptom score sheets each day of the 1978 and 1979 ragweed pollen seasons. Beginning in March, 1979, all patients except one received 15 weekly injections of PRW totaling 50,000 protein nitrogen units (PNU) and containing about 500 μg ragweed AgE. One patient received 25,000 PNU. Symptom score indices of the posttreatment 1979 season were compared with those from the pretreatment 1978 season and also with the scores of similar groups of ragweed-sensitive patients in each city treated only with medication for symptomatic relief during the 1979 season. Local reactions to polymerized ragweed immunotherapy were minimal. No abnormalities in complete blood count, erythrocyte sedimentation rate, chest x-ray film, urinalysis, or rheumatoid factor occurred in the immunotherapy-treated groups. Total serum antibody binding of ragweed AgE increased 12-fold following immunotherapy. When compared either with their 1978 untreated group scores or when compared with scores from the untreated group in each city in 1979 (control group), the symptom score indices of the immunotherapy-treated groups in 1979 were significantly improved. PRW is efficacious in the treatment of ragweed hay fever and can be administered more safely and in higher doses with fewer injections than conventional extracts. It represents an improved form of immunotherapy.