Hipersensitivity to Ficus benjamina

Background: Ficus benjamina is a plant belonging to the Moraceae family; although it does not bloom, it may be a source of indoor allergens. The aim of the present study was to assess the prevalence of exposure and sensitization to Ficus benjamina in our environment, the clinical expression of such sensitization, and the possible cross reactivity with other allergens. Patients and methods: a total of 347 patients attending the Allergy Unit of a general hospital were studied. Extracts prepared from the leaves and stems of Ficus benjamina were used for skin tests, for specific IgE quantitation (enzyme immunoassay) and SDS-PAGE immunoblotting. The serum specific IgE concentrations were also measured using the Pharmacia CAP-system. In those patients who were hypersensitive to Ficus benjamina, skin tests to common edible fig, kiwi, bromelin, papain, latex and mulberry tree pollen were also performed. Results: Exposure to Ficus benjamina or other Ficus species was documented in 101 (29%) patients. Twenty-two of them were sensitized to Ficus benjamina, but only four had symptoms when immediately exposed to the plant. The specific IgE was positive in four out of ten patients by enzyme immunoassay, and in two out of nineteen by the CAP-system. SDS-PAGE immunoblotting demonstrated the presence of IgE-fixing proteins with molecular weights ranging between 8 and 42 kDa. Out of the 22 patients with hypersensitivity to Ficus benjamina, eight evidenced hypersensitivity to common edible fig (three of them with associated symptoms), seven to kiwi (three with symptoms) and two to latex (one with symptoms). Conclusions: both the prevalence of exposure and sensitization to Ficus benjamina and the presence of allergic manifestations in some patients lend support to the consideration of this plant as an indoor allergen which may also have implications in food allergy.