Objective: The aim of this study was to determine whether IgG(4) antibodies to allergens in urine extracts from fur animals associated with positive prick tests to the same allergens and with the occurrence of respiratory symptoms among fur workers, especially among highly exposed fur farmers.
Methods: Among the fur workers and among their referents, IgG(4) antibodies to mink and silver fox urine were analysed in three groups; all workers with a positive skin prick test to any fur animal allergen (n=50), all workers who had reported shortness of breath or rhinitis or eye symptoms (n=159), and to a random sample of asymptomatic persons (n=178). In the two last groups none of the workers had a positive skin test to any fur animal allergen.
Results: The fur farmers had higher level of IgG(4) values than other groups and also had positive IgG(4) antibodies to urine extract more frequently than the other groups. Among the exposed subjects, there was a distinct overlapping of a positive skin prick test to fur urine allergens and positive IgG(4) antibodies to responding allergens. Among the fur farmers the IgG(4) levels were associated with symptoms.
Conclusions: IgG(4) antibodies were shown to be a good indicator of exposure. Because of an overlapping of positive skin prick tests and IgG(4) response to the same allergens, and an association between symptoms and IgG(4) response, it is recommended that the potential role of IgG(4) antibodies as an indicator of alternative sensitisation should be further examined in prospective studies.