Response of sawmill workers to work-related airborne allergens

The aim of this work was to determine the reactivity of sawmill workers to biological allergens associated with wood dust. Allergological examinations by skin and precipitin tests were performed in 43 workers employed in a sawmill processing coniferous wood (pine), in 90 workers employed in two sawmills processing deciduous wood (oak), and in 32 healthy urban dwellers not exposed to organic dusts (referents). The skin test was performed by the intradermal method with the saline extracts of wood dust and of the cultures of three microbial species (Rahnella sp., Brevibacterium linens and Penicillium citrinum) isolated from the air polluted with wood dust. Sawdust from pine was used for testing of the pine processing workers and referents while sawdust from oak was used for testing of the oak processing workers. Skin reactions were recorded after 20 minutes, 8 hours and 24 hours. The agar-gel test for the presence of precipitins in serum was performed with the extract of pine wood dust and extracts of 17 microbial isolates. The workers processing pine showed a very high frequency of positive skin reactions to the extract of wood dust at all time intervals, significantly greater compared to the workers processing oak and referents (p < 0.001). The early skin reactions to the extracts of dust-borne bacteria and fungi were very common among sawmills workers and showed a significant relationship with the degree of exposure. The frequency of reactions to Gram-negative bacterium Rahnella sp. was significantly greater in the pine processing workers than in the oak processing workers and referents (p < 0.001). By contrast, the oak processing workers reacted significantly more frequently to Penicillium citrinum, compared to the pine processing workers and referents (p < 0.01). These results conform to the prior study of airborne microflora in which the dominancy of Gram-negative bacteria was stated in the pine processing sawmill while mould fungi were most common in the oak processing sawmills. The antibody response of sawmill workers to work-related antigens was much weaker compared to skin reactions. As many as 41 sawmill workers reported the occurrence of work-related symptoms. A significant relationship was found between the occurrence of symptoms and frequency of allergic reactions, but only with a limited number of antigens. The obtained results suggest that early allergic reactions to coniferous wood and to microorganisms associated with wood dust are common among sawmill workers, posing a potential risk of work-related disease in this occupational group.