Abstract

The serological response to Aspergillus fumigatus was investigated in patients with pulmonary aspergillosis using the immunoblot technique. Antibody was detected against nine components of the fungus, ranging in molecular weight from 88 000 to 33 000 daltons. Antibody to a 40 000 dalton component was present in most patients (13 of 16). In surviving patients it was high (two with aspergilloma) or low but persistent (two with invasive aspergillosis). It was absent or fell in the 12 patients who died of invasive aspergillosis. Antibody to this 40 000 dalton antigen was not present in 10 sera from healthy controls. This antigen may form the basis of a more sensitive and specific serodiagnostic test for systemic aspergillosis.