Inhaled aeroallergen and storage mite reactivity in a Wisconsin farmer nested case-control study

A nested case-control study was undertaken to assess the role of antibody (Ab) to a panel of antigens associated with hypersensitivity pneumonitis in the development of lung disease among Wisconsin dairy farmers. Immunologic reactivity to a panel of inhaled allergens was assessed in the Ab+ cases and compared to the Ab+ control, Ab- control, and Ab- blue-collar control subjects by skin tests, RAST assays, and a modified American Thoracic Society questionnaire. The most prevalent allergens among the cases as determined by either skin test or RAST assays were the house dust mites (HDM) (21.6%), storage mites (11.2%), grain smuts (11.2%), Cladosporium (7.5%), Aspergillus (6.0%), and cattle (5.2%). No other allergens appeared to be different from in nonfarming populations. Of the storage mite reactors, IgE to Lepidoglyphus destructor (7 of 8) was the most frequently found, followed by Tyrophagus putrescentiae (6 of 8), Glycyphagus domesticus (5 of 8), Chortoglyphus arcuatus (5 of 8), and Acarus siro (2 of 8). L. destructor was also isolated from the farm of one of the cases. There was no difference in the total IgE levels among the groups. Reactions to HDM, storage mites, and grain smuts were significantly more frequent among the cases (p < 0.05). We conclude from this study that there is a significant increase in reactivity to certain inhaled allergens among those dairy farmers reporting barn-associated respiratory symptoms that is unrelated to past exposure to the causative agents of farmer's lung disease.