Juniperus oxycedrus: a new allergenic pollen from the Cupressaceae family.

Background: Cupressaceae allergy is a worldwide pollinosis caused by several species. Some species in limited geographic areas pollinate in fall and winter. Juniperus oxycedrus matches these features.

Objective: We sought to define the immunochemical, allergologic, and environmental aspects of J. oxycedrus pollen.

Methods: Pollen extract from J. oxycedrus was prepared and characterized by biochemical analysis and human specific IgE binding by means of ELISA and immunoblotting. A 3-year phenological study was conducted to define the pollinating period of J. oxycedrus. Forty consecutive patients allergic to cypress were recruited in two areas and divided into two groups according to their exposure to J. oxycedrus pollen. Clinical evaluation, skin prick tests, and specific IgE determination with J. oxycedrus, J. ashei, and Cupressus arizonica extracts were carried out on both groups.

Results: J. oxycedrus pollen extract was obtained, and it showed specific IgE binding and wide cross-reactivity with other Cupressaceae species. The extract caused a positive skin test response in all the patients tested, with about 80% of them having detectable specific IgE. Symptoms related to J. oxycedrus pollen exposure were recorded in 72% of the directly exposed patients and occasionally in 9% of the nonexposed patients. In the Mediterranean coastal area considered, J. oxycedrus was the first Cupressaceae species that started to pollinate at the beginning of November and ended in the first part of December.

Conclusions: J. oxycedrus represents a newly characterized pollen species of the Cupressaceae family that cross-reacts with other members of the same family. Subjects with cypress allergy have in vivo and in vitro positive test responses for J. oxycedrus and can show symptoms when exposed to its pollen. Finally, the most important feature of J. oxycedrus is its early pollinating period in southern Europe (Italy), causing a further extension of the cypress pollen season in areas where other Cupressaceae species are present.