Efficacy of grass-maize pollen oral immunotherapy in patients with seasonal hay-fever: a double-blind study.

Forty patients with a well-documented history of seasonal hay fever and a positive skin-prick test specific to grass pollen, including Bermuda grass and maize pollen (Zea maize), were allocated randomly on a double-blind basis to receive either an oral mixed grass-maize pollen extract or a matched placebo during the 1981/1982 grass pollen season. After 12 months the code was broken and patients on placebo were transferred to active therapy while patients on active therapy continued with maintenance therapy for another 12 months during the 1982/1983 grass pollen season. The assessment of the effect of the orally administered grass-maize pollen extract was on the clinical symptoms. During the first year the patients on active therapy had significantly fewer hay fever symptoms during the summer months compared with the placebo group. During the second study year, with all patients on active therapy, both groups had markedly milder symptoms compared with the placebo group. Side-effects were negligible. This study concludes that oral immunotherapy with grass-maize pollen extract in grass pollen-sensitive seasonal hay fever patients is safe and effective.