Serum IgG Antibodies Against Wallemia sebi and Fusarium Species in Finnish Farmers

Wallenia sebi and Fusarium species are common fungi in agricultural environments. Because Fusarium species are difficult to culture, and W. sebi has only recently been found in an agricultural environment with the use of a new culture medium, immunochemical methods may be important for evaluation exposure to these fungi. Immunoglobulin (Ig) G antibodies against W. sebi and two Fusarium species were measured in the sera of Finnish farmers to estimate exposure to fungi. Serum-specific IgG antibody levels against the fungi were determined in farmers with farmer's lung disease and asthma, as well as in asymptomatic farmers with low and high IgG antibody levels against other agricultural microorganisms, and in control persons (printing and office workers). Both enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunofiltration assay (ELIFA) techniques were used. Significantly higher IgG antibody levels against the fungi studied were observed in farmer's lung patients and symptomatic farmers with high IgG levels against other agricultural fungi, than in the control group. On the other hand, the development of IgG antibodies to the fungi in asthmatic farmers remained unclear because of a discrepancy between the ELISA and ELIFA results. Cross-reactivity between Fusarium was detected. The results indicate that Finnish farmers are exposed to W. sebi and Fusarium species in their work environment to a greater extent than has earlier been evaluated with air sampling and microbiologic methods.