Serum antibodies to Aspergillus fumigatus in patients with rheumatic diseases.

IgG and IgA serum antibodies to Aspergillus fumigatus were determined in 47 patients with rheumatic disorders, 4 patients with pulmonary aspergillosis associated with rheumatic disease, and in 36 healthy controls. Antibody titres determined by indirect immunofluorescence were comparable in patients with rheumatic diseases and in controls, except for 2 patients with IgG antibody titres within the upper range of patients with aspergillosis. IgG antibody levels to 2 partially purified A. fumigatus antigens (I and VIII), determined by enzyme-linked immunosorbent assay (ELISA), were higher in rheumatic patients than in controls and with antigen VIII the difference reached statistical significance for all subgroups of rheumatic patients. IgA antibody levels by ELISA were also increased in rheumatic patients compared with the control group: IgA levels against antigen I fell within the range of patients with aspergillosis in 7 patients with rheumatic disorders. This suggests that some rheumatic patients are more strongly sensitized to Aspergillus antigens than normal subjects.