Occupational asthma caused by Arabidopsis thaliana: a case of laboratory plant allergy.

A 36-yr-old male never-smoker with an 8-yr history of hay fever but no past history of asthma undertook a 3-yr research project involving the plant Arabidopsis thaliana. The subject was based in a small laboratory with an attached growing room. After 30 months of research, he began to develop breathlessness within 5-10 min of entering the laboratory. Initial investigations confirmed asthma with airflow obstruction (forced expiratory volume in one second (FEV(1))/forced vital capacity was 3.01/4.75 L; predicted values were 3.67/4.43 L) and increased airway responsiveness. Serial peak expiratory flow measurements showed a work-related pattern. A supervised workplace challenge test led to a fall in FEV(1) from the baseline value of 3.10 L to 1.95 L within 20 min of entering the growing room. Skin-prick solutions were prepared from Arabidopsis leaves and flower heads; positive 4-mm responses were obtained to the flower heads (i.e. to the pollen). Arabidopsis is a member of the Brassicaceae family. It is used extensively in plant biology research as its genome is small, has been fully sequenced and is easily manipulated. The present article represents the first reported case of occupational asthma due to Arabidopsis thaliana.