Occupational asthma due to IgE mediated allergy to the flower Molucella laevis (Bells of Ireland)

Abstract

Background: About 25% of greenhouse flower and/or ornamental plant growers sensitised to workplace flowers or moulds have occupational asthma, a disease that is suffered by 8% of the growers who cultivate these crops. Aim: To document a case of occupational asthma due to IgE mediated allergy to the flower Molucella laevis. Methods and Results: There was a history of work related seasonal asthmatic and rhinoconjunctivitis symptoms in a Molucella laevis grower. Bronchial obstruction following exposure to Molucella laevis was documented by a fall in FEV1 from 89% to 73% of predicted during seasonal exposure to Molucella laevis. Daily PEF measurements showed a fall from 500 to 250 l/min during this period following withdrawal of inhaled steroids. Bronchial reactivity to inhaled methacholine was increased (PC 20 1.45 mg/ml). Confirmation of sensitisation to Molucella laevis flower pollen extract was done using an SPT and by demonstration of Molucella laevis specific serum IgE (18 IU/ml; class 4). Specific inhalation challenge with Molucella laevis extract provoked an early and late asthmatic reaction (EAR and LAR) with a fall in FEV1 compared with control day of 40% and 53% respectively, with associated 5.1-fold increase in absolute sputum eosinophil cell counts and 2.9-fold increase in neutrophil cell counts.