Occurrence of Aspergillus umbrosus antibodies in Danish farmers

Antibodies to Aspergillus umbrosus were investigated in 181 Danish farmers, 137 farmers' spouses and a control group of 104 male blood donors with no relation to farming. By enzyme-linked immunosorbent assay (ELISA) higher levels of IgG antibodies were found in farmers than in their spouses and in non-farming controls (P less than 0.0001). By double immunodiffusion precipitating antibodies occurred in 11 farmers, in none of farmers' spouses and in one control subject. Farmers and farmers' spouses who were non-smokers had higher IgG antibody levels than smokers in the same groups (P less than 0.04). Farmers more than 30 years of age had higher IgG antibody levels than younger farmers (P less than 0.04). Farmers rearing cattle tended to have higher IgG antibody levels than farmers without cattle. No correlation between antibody levels and respiratory symptoms or lung function parameters (FEV1 or FVC) could be demonstrated.