Serum antibodies to aspergillus fumigatus in patients with pulmonary aspergillosis detected by immunofluorescence.

Aspergillus antibodies of the IgG, IgA and IgM class were determined by the indirect immunofluorescence (IIF) technique in sera from 11 patients with proven pulmonary aspergillosis (group I), 11 patients with suspected pulmonary aspergillosis (group II), 34 patients with chronic obstructive lung disease (group III), 29 patients with lung infiltrates of non-fungal aetiology (group IV), and 94 blood donors (group V). The antigen was cryostate sections of formaldehyde fixed mycelium. IgG antibody titres above 640 occurred in 73% in group I + II, 12% in group III, 0% in group IV, and 22% in group V. The difference between group I + II and group V was statistically significant (p less than 0.001). IgA antibody titres above 80 were only found in patients in group I + II, suggesting that demonstration of such antibodies may be of diagnostic significance. IgM antibodies in titres between 10 and 160 were found in 100-65% in group I to V. Precipitating antibodies to a culture filtrate antigen occurred in all subjects in group I, in 9 (82%) in group II, and in 1-7% of subjects in group III to V. However, precipitin titres above 2 occurred only in group I and II. No correlation between precipitin titres and IIF titres of IgG and IgA antibodies was obtained, suggesting that the two methods reveal antibodies of different specificities.