Comparison of antibody measurements against Aspergillus fumigatus by means of double-diffusion and enzyme-linked immunosorbent assay (ELISA).

IgG antibody titers against Aspergillus fumigatus from different sera were measured by means of a standardized ELISA and compared with precipitates measured by double diffusion (D.D.). There was a significant correlation between the number of precipitates and the ELISA IgG titers in the 758 sera examined. However, in several individual sera within this group, large deviations between these two immunologic parameters were found. Further analysis indicated that ELISA detects antibodies against nonprecipitating antigenic components in addition to the antibodies detected by D.D. Furthermore, not all precipitating antigenic components appear to play a role in the detection of antibodies against A. fumigatus by ELISA. Patients with aspergillosis largely show increased titers of IgG antibody by ELISA even when the results of D.D. are negative, except those of patients with Aspergillus-provoked asthma which fall within a normal range.