Background: Cypress and olive pollen are the most prevalent sensitizers in the Mediterranean area. Some patients exhibit dual sensitization, which has not been well documented to date.
Objective: To identify the allergens involved in dual cypress and olive allergy (C+O) and to study the relationship between phenotype and allergen sensitization.
Methods: C+O patients were selected. Those monosensitized to olive or cypress were used as a reference. Specific IgE to whole extracts and purified allergens from olive and cypress was determined. Immunoblotting was performed to analyze IgG and IgE binding using olive polyclonal antibodies and patients’ sera, respectively. Mutual immunoblotting inhibition of olive and cypress extracts and inhibition of
cypress extract immunoblotting with olive allergens were performed. Multiple correspondence analysis and hierarchical cluster classifications were conducted to analyze the relationships between the clinical presentation of C+O (symptoms, seasonality) and allergen profile.
Results: C+O patients were clustered in 4 phenotypes. The most frequent one (58.4%) was rhinoconjunctivitis in winter (February) and spring (May), with asthma in 38% of patients. Ole e 1 and Cup s 1 were the major allergens. Proteins homologous to Ole e 1, Ole e 9, and Ole e 11 in cypress pollen were identified and shown to inhibit IgE binding to cypress extract.
Conclusions: The exclusive C+O results from cosensitization to Cup s 1 and Ole e 1 and cross-reactivity due to previously unreported Ole e 1–like, Ole e 9–like, and Ole e 11–like allergens in cypress pollen. Our findings point to 4 clinical phenotypes of winter and/or spring or perennial rhinoconjunctivitis with and without asthma.

Key words: Allergen, Cypress pollen, Cluster analysis, Cross-reactivity, Multiple correspondence analysis, Olive pollen