Vaccine development and new attempts of treatment for ragweed allergy.

Ragweeds are flowering plants in the genus Ambrosia in the aster family, Asteraceae. They are distributed in the tropical and subtropical regions of the New World, especially North America. Short ragweed is the most important weed. The ragweed flowering occurs late in the summer and the pollination period extends from the beginning of August to mid-October. Sensitization to ragweed pollen has risen in United States in the past decade and probably worldwide. The major allergenic compound in the pollen has been identified as Amb a 1. Ragweed allergies usually cause allergic rhinitis and asthma. Ragweed allergic patients may show signs of oral allergy syndrome caused by crossreactivity between ragweed allergens and food allergens. In the present article, an update about vaccine development and new knowledge for ragweed allergy is exhaustively revised.