Comparison of Aspergillus fumigatus and Aspergillus umbrosus antigens in serological tests of farmer's lung.

A comparison was made between Aspergillus fumigatus and A. umbrosus antigens regarding their usefulness in serological tests of farmer's lung. Mycelial and culture fluid antigens of both microbes were used to test sera of 30 Finnish farmer's lung patients for antibodies in the ELISA and in the gel precipitation (GP) test. Antibodies to A. umbrosus were more common than to A. fumigatus; this was especially evident in ELISA, ELISA gave more positive results with all four antigens than GP. Mycelial antigens showed more positive reactions in ELISA than the corresponding culture fluid antigens. The situation was reversed in GP. Selection of antigens in the diagnostic panel of farmer's lung requires careful consideration. Our results suggest that other Aspergilli (in the Finnish population A. umbrosus) might be preferable to A. fumigatus in the antigen panel.