OCCUPATIONAL ALLERGY IN GREENHOUSE WORKERS - SENSITIZATION TO TETRANYCHUS-URTICAE

Background Tetranychus urticae (TU) is a macroscopic mite which is fou nd infesting a large number of plants of economic interest. It has rar ely been described as a cause of occupational allergic disease in agri cultural workers. Objective To describe TU sensitization in greenhouse workers attending the outpatient allergy unit and its clinical associ ations, and to characterize the allergens involved. Materials and meth ods Twenty-four consecutive carnation greenhouse workers with allergy- related symptoms. referred to our outpatient clinic during a 6-month p eriod, wore included. We made the diagnostic extract from carnation le aves heavily infested with TU. Skin-prick test, specific IgE measureme nt and bronchial provocation test with TU extract were carried out in all subjects. Allergen characterization was achieved by SDS-PAGE (sodi um dodecylsulfate-polyacrylamide gel electrophoresis) and immunoblotti ng. Results Sixteen patients (66%) presented positive skin-prick test and specific IgE and were diagnosed allergic to TU. Fifteen patients s uffered from bronchial asthma, 14 rhinitis and five urticaria. Twelve exibited positive bronchial provocation test to the TU extract. On RAS T-inhibition studies, there was no evidence of crossreactivity between TU extract and D. pteronyssinus. An allergen at 19 kDa was determined in the TU extract by SDS-PAGE immunoblotting studies. Conclusion TU c ould be an important occupational allergen in greenhouse workers showi ng allergic symptomatology. There is no crossreactivity between this m ite and the house dust mite D. pteronyssinus.