Abstract
To evaluate type I hypersensitivity to grain dust (GD), its prevalence and
relationship to respiratory dysfunction, we studied clinical and immunologic
features, including skin prick tests (SPT), serum specific IgE, and
bronchoprovocation tests of 43 employees working in the animal feed industry. To
further characterize IgE-mediated reaction, SDS-PAGE and electroblot studies
were performed. Our survey revealed that 15 (34.9%) subjects had work-related
skin response (≥2+ of A/H ratio) to GD, thirteen (30.2%) had high specific
IgE antibody against GD. The specific IgE antibody was detected more frequently
in symptomatic workers (40%) than in asymptomatic workers (11%). Significant
association was found between specific IgE antibody and atopy or smoking
(p<0.05). The ELISA inhibition test of GD revealed significant inhibitions by GD
extract and minimal inhibitions by the house dust mite, storage mite and corn
dust. Immunoblot analysis showed 8 IgE binding components within GD ranging from
13.5 to 142.5 kDa. Two bands (13.5, 33 kDa) were bound to the IgE from more than
50% of the 14 sera tested. In conclusion, these findings suggest that GD
inhalation could induce IgE-mediated bronchoconstriction in exposed workers.