IgG antibodies to Aspergillus fumigatus, Thermoactinomyces vulgaris, or Micropolyspora faeni may be found in sera from healthy individuals; the presence of these specific antibodies is not sufficient to establish the diagnosis of hypersensitivity pneumonitis (HP).
Elevated concentration of antibodies to Aspergillus fumigatus may be also found in patients with invasive aspergillosis and cavitary lung disease.
The concentrations of antibodies to these antigens may decrease following treatment, although elevated concentrations may persist in treated patients.