Aspergillus fumigatus antigen detection in sera from patients at risk for invasive aspergillosis

We have developed an inhibition enzyme immunoassay (inhibition-EIA) to moni tor for the occurrence of invasive aspergillosis (IA) in sera from 45 immun ocompromised (IC) patients, The test uses rabbit polyclonal antibodies and a mixture of components from Aspergillus fumigatus, containing three predom inant antigens with molecular weights of 18,000, 33,000, and 56,000. Circul ating antigens were found in five of seven proven cases of IA due to A. fum igatus. In two of the five positive cases, antigenemia was detected with in hibition-EIA earlier than with X ray or other biological methods. No antige ns were detected in the sera from two patients with proven IA due to. Asper gillus flavus and Aspergillus terreus nor in the sera from four patients wi th probable IA. Circulating antigens were not detected in the control group , composed of 30 healthy adult blood donors. Four of the 32 at-risk patient s examined, though they displayed no definite evidence of IA gave a positiv e result in this test. The sensitivity, specificity, and positive predictiv e value of inhibition-EIA were 71.4, 94.4, and 71.2%, respectively. The dat a were compared with those obtained by a latex agglutination assay of galac to-mannan (GM) that was positive in only one patient with probable IA. The higher sensitivity obtained by inhibition-EW may well be due to its ability to detect circulating antigens other than GM in the sera of IC patients wi th IA detecting these antigens may improve the diagnosis of IA, as they may serve as markers of this infection.