Prevalence of allergic sensitization to conifer pollen in a high cypress exposure area

Sensitization to Pinales (Cupressaceae and Pinaceae) has increased dramatically in recent years. The prevalence of sensitization in different geographic areas is related to exposure to specific pollens.

To investigate the prevalence of allergy to different conifer pollens, describe the characteristics of patients with such allergy, and identify the involved allergens.

Patients were recruited at five hospitals near Madrid. Extracts from conifer pollen were prepared and used in skin-prick testing. Wheal sizes were recorded, and serum samples obtained from patients with positive reactions to Cupressus arizonica and/or Pinus pinea. The specific immunoglobulin E value to C. arizonica and Cup a 1 was determined. Individual immunoblots for each patient and with a pool of sera were performed. Allergenic proteins were sequenced by using liquid chromatography-tandem mass spectrometry.

Of 499 individuals included in the study, 17 (14%) had positive skin-prick test results to some conifer pollen extracts. Sixty-four patients had positive results to C. arizonica (prevalence 12.8%) and 11 had positive results to P. pinea (2.2%). All the patients had respiratory symptoms (61.4% during the C. arizonica pollination period), and 62.9% had asthma. Approximately 86% of the patients had positive specific immunoglobulin E results to C. arizonica and 92.3% had positive results to Cup a 1. Fourteen different bands were recognized by immunoblot; the most frequent bands were those detected at 43, 18, 16, and 14 kDa. All sequenced proteins corresponded to Cup a 1.

Allergy to conifer pollen could be considered a relevant cause of respiratory allergy in central Spain. Asthma was more frequent than in other studies. We only identified Cup a 1 as involved in sensitization.