Controlled studies of intranasal immunotherapy for ragweed pollenosis.

During 1978 a double blind study compared the efficacy of preseasonal short ragweed (RW) extract intranasal immunotherapy with a histamine placebo; in 1979 more prolonged treatment with a larger dose of polymerized ragweed (PRW) was evaluated. In neither year did the placebo-treated patients show significantly more severe disease as assessed by daily symptom diaries, examination in season, comparison of overall symptom severity with previous years or changes in nasal challenge tests. Following treatment in 1979 there was a significantly greater amount of secretory IgA and IgG ragweed antibodies secreted by the nose of the PRW-treated group, but these titers did not correlate with clinical results.