Role of Dau c 1 in three different patterns of carrot-induced asthma

Abstract

Objective: To assess the role of Dau c 1 in three patients with carrot induced asthma.

Material and methods: Patient 1 had asthma when handling raw carrots. Sensitization to pollens wasn't detected. Patient 2 had rhinoconjunctivitis due to grass and olive pollen allergy. She had asthma when handling raw carrots. Patient 3 was diagnosed of rhinoconjunctivitis and asthma due to allergic sensitization to mites, several pollens and cat. She had asthma due to raw carrot ingestion and inhalation. IgE immunobot analysis and ELISA inhibition assay were used to investigate the allergens and specific antibodies.

Results: IgE Immunoblot Analysis: Dau c 1 from carrot extract and the recombinant rDau c 1 were recognized by IgE from patients 1 and 2. Band of Bet v 1 in birch pollen extract wasn't recognized. Patient 3 didn't recognize any of these allergens. Specific IgE to rDau c 1 was measured by ELISA. Specific IgE ELISA-inhibition with carrot as solid phase showed an intermediate inhibition (30 %) between carrot and rDau c 1 in patient 1; and a considerable inhibition (nearly 100 %) between carrot and rDau c 1 in patient 2. No inhibition was found in patient 3. Specific IgE ELISA inhibition between rDau c 1 and rBet v 1, employing rDau c 1 as solid phase was made in patients 1 and 2. Bet v 1 showed less than 40 % of inhibition of rDau c 1 in patient 1; and an intermediate inhibition (> 40 %) between rBet v 1 and rDau c 1 in patient 2.

Conclusions: Airborne carrot allergens are able to sensitize without the implication of a previous pollen allergy. Dau c 1 was the main allergen in patient 2. In patient 1, there was a band of 30 kd that looks like the predominant allergen. Patients 1 and 2 were sensitized directly from carrot allergens. In patient 3, Dau c 1 isn't related to the carrot allergy. Allergy to carrot in patient 3 seems to be related to her allergy to different pollens; however, it wasn't related to birch pollen. Mediterranean countries didn't show the same patterns of food-related pollen allergy than Nordic countries.