Allergy to Diplotaxis erucoides pollen: occupational sensitization and cross-reactivity with other common pollens

BACKGROUND: Diplotaxis erucoides is a common weed of the Brassicaceae family widespread in southern and central Europe. METHODS: A total of 410 consecutive patients referred for allergy study of rhinoconjunctivitis and/or asthma were skin tested with D. erucoides pollen, 14 proving positive. A purified D. erucoides pollen extract was prepared to perform quantitative skin tests, provocation tests, immunoblotting, and EIA inhibition in the 14 sensitized patients. RESULTS: Three patients, directly involved in viniculture, had rhinoconjunctivitis related to D. erucoides pollen. No D. erucoides-related symptoms were observed in most patients, who were also sensitized to Artemisia pollen. RAST was positive in 12/14 patients and nasal provocation tests in 9/12. The molecular masses of the most prevalent IgE-binding proteins ranged from 26 to 27.5 and from 31 to 34 kDa. D. erucoides pollen inhibited the IgE-binding of other sensitizing pollens in the three viniculture workers, whereas both Artemisia and D. erucoides pollen produced similar heterologous inhibition in the pooled serum of the remaining, nonclinically affected, D. erucoides-sensitized patients. CONCLUSION: D. erucoides pollen may be an important prevalent aeroallergen, particularly in rural areas. It may act as an occupational allergen in vineyard workers, in whom it seems to be the primary sensitizing agent, playing a secondary cross-reactive role in other sensitized patients.