Detection of fungal antigen in body fluids for diagnosis of invasive aspergillosis

Abstract

In clinical trials, the diagnostic utility of a radioimmunoassay (RIA) to detect Aspergillus antigen was demonstrated in sera obtained from patients with invasive pulmonary, endothelial, and disseminated aspergillosis, in cerebrospinal fluids from patients with Aspergillus meningoencephalitis, and in bronchoalveolar lavage fluids from patients with invasive pulmonary aspergillosis. The RIA was further evaluated in three blinded, controlled clinical trials. In one, sera were collected prospectively from patients with acute leukemia. Antigenemia was detected in four patients with invasive pulmonary aspergillosis (IPA) due to A. flavus, appeared early in the course of infection of three patients concurrent with the onset and evolution of lung infiltrates, and remitted with antifungal chemotherapy. Antigenemia was not detected in three patients before the onset of IPA, in eight leukemic controls, or in the 24 normals. In contrast, seven bronchoscopies were performed in five patients with IPA; fungi were not isolated in three. In a second study, antigenemia was found in coded sera from two patients with invasive aspergillosis but not in eight controls. In the third controlled study, 616 sera from 79 hematology patients admitted on 152 occasions were analyzed for circulating fungal antigen. The diagnostic utility of the RIA was confirmed and levels of antigenemia correlated with the patients' clinical course. These studies demonstrate the utility of the Aspergillus antigen RIA for diagnosis of invasive aspergillosis in hospitalized high risk patients.