Occupational asthma associated to the exposure to limonium tataricum flowers

Limonium tataricum (Lt) is a plant belonging to the family of Plumbaginaceae. The role of this family and in particular, that of dried flowers (but not of the pollen) in occupational allergy has already been described. We have observed a farmer with asthma occurring in the presence of fresh flowers. Standard methacoline test demonstrated that the patient was a true asthmatic. The allergenicity of Lt pollen was thus investigated Skin prick tests (SPT) were carried out using both standard allergens and the Lt extract and the patient's mucosal reactivity was evaluated by nasal provocation test with the pollen extract. In vitro studies were also performed on the patient's serum by evaluating routine specific anti-allergen IgE on raw extracts and on Microarray Allergen Chip (ISAC). Finally, the raw extract of the fresh Lt pollen was also used in ELISA inhibition test, immunoblotting and Basophil Activation Test (BAT). The specific sensitization was demonstrated by Skin Prick test and nasal provocation test. The sensitization was also confirmed by specific IgE and by in vitro activation of basophils in the presence of the pollen. By using RAST inhibition test, the presence of cross-reactivity with other pollens was ruled out. According to our results, Lt extracts contain an allergenic activity not only as dried flowers, but also as fresh pollen. For its role in occupational asthma, this allergen should be included in any allergy screening at least in farmers or in the flower industry employers.