Serum antibodies and their role in antibody-dependent cell-mediated cytotoxicity in aspergillosis

A total of 22 sera from patients with aspergilloma and allergic bronchopulmonary aspergillosis (ABPA) were examined concomitantly for specific antibody against Aspergillus fumigatus antigen and for their activity in antibody-dependent cell-mediated cytotoxicity (ADCC) against Aspergillus antigen-coated target cells. These sera demonstrated significant precipitin bands in agar gel double diffusion test (78% of ABPA and 75% of aspergilloma sera), while in indirect immunofluorescence studies all sera showed positive reactivity with a titer distribution of 1:40 to 1:160 and 1:40 to 1:320, respectively, for ABPA and aspergilloma sera. In enzyme-linked immunosorbent assay all sera demonstrated titers varying from 1:200 to 1:6400. Several sera also displayed marked cytotoxic reactions against A. fumigatus antigen coated SB target cells in ADCC assays using normal lymphocytes as effector cells (35% of aspergilloma and 25% of ABPA sera). These findings suggest a role for ADCC activity in patients withAspergillus infections.