Antigen detection in the diagnosis of invasive aspergillosis. Utility in controlled, blinded trials

Abstract

Two blinded, controlled trials were done to evaluate the usefulness of fungal antigen detection for the diagnosis of invasive aspergillosis. Detection of Aspergillus fumigatus carbohydrate by radioimmunoassay was compared with antibody detection by an enzyme-linked immunosorbent assay and with diagnostic microbiologic and histopathologic procedures. In the first trial, antigenemia was detected in 4 of 6 leukemic patients with invasive pulmonary aspergillosis, but not in 8 acute leukemic controls or in 24 normal controls. Fungal antigenemia persisted for 8 to 75 days in 4 patients and seroconversion occurred at the onset of pulmonary infiltrates in 3. Antibody to A. fumigatus was detected in 2 of the 6 patients with aspergillosis, but also in 2 leukemic controls and 6 normal controls. Aspergillus species were identified in four of seven bronchoscopies done in 5 patients with invasive pulmonary aspergillosis. Prospective nasal cultures grew Aspergillus species in 4 of the 6 patients with invasive aspergillosis, but in only 1 patient was this information available before a histologic diagnosis was made. In a second trial, antigenemia was detected in 2 patients with invasive aspergillosis, and in 1 with possible invasive aspergillosis, but not in 9 controls. This study indicates that the radioimmunoassay for A. fumigatus antigen is a highly specific and moderately sensitive serodiagnostic test for invasive pulmonary aspergillosis. Prospective nasal cultures grew Aspergillus species in 4 of the 6 patients with invasive aspergillosis, but in only 1 patient was this information available before a histologic diagnosis was made. In a second trial, antigenemia was detected in 2 patients with invasive aspergillosis, and in 1 with possible invasive aspergillosis, but not in 9 controls. This study indicates that the radioimmunoassay for A. fumigatus antigen is a highly specific and moderately sensitive serodiagnostic test for invasive pulmonary aspergillosis.