IGG AND IGA SUBCLASS ANTIBODIES AGAINST ASPERGILLUS-UMBROSUS IN FARMERS LUNG-DISEASE

Fifty patients with farmer's lung disease (FL), 20 asymptomatic expose d farmers, and 18 healthy controls were investigated for total IgG and total IgA, as well as subclass antibody levels against Aspergillus um brosus, the most common fungus to which FL patients in Finland have be en exposed. Enzyme-linked immunosorbent assay (ELISA) revealed signifi cantly elevated levels of specific total IgG and IgA antibodies in the sera of patients during the acute phase of the disease. Both IgG1 and IgG2 subclass antibodies and both IgA1 and IgA2 subclass antibodies w ere significantly associated with the disease. The antibody levels dec reased during the first 3 months, when mould exposure was avoided and when an oral 6-week steroid treatment was administered. During the nex t 12 month follow-up, the mean antibody levels continued to decrease, even though re-exposure might have occurred. The results (with sensiti vity 94% and specificity 95%) imply that in addition to the measuremen t of A. umbrosus-specific IgG, determination of both A. umbrosus-speci fic IgG1 and IgA might also be useful in the serodiagnosis of acute st age of FL.