Prospective evaluation of a polymerase chain reaction-ELISA targeted to Aspergillus fumigatus and Aspergillus flavus for the early diagnosis of invasive aspergillosis in patients with hematological malignancies

Abstract

Background: Current laboratory and radiological methods for diagnosis of invasive aspergillosis (IA) lack sensitivity and specificity.

Methods: We prospectively evaluated the diagnostic value of twice-weekly screening for circulating Aspergillus fumigatus and A. flavus DNA with a polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA).

Results: Among the 201 adult patients with hematological malignancies who were included in the study, 55 IA cases were diagnosed. On the basis of the analysis of 1205 serum samples from 167 patients, the sensitivity, specificity, and positive and negative predictive values of the PCR-ELISA for proven and probable IA cases were 63.6%, 89.7%, 63.6%, and 89.7%, respectively, when samples with 2 consecutive positive results were used. The use of a combination of the PCR-ELISA and a galactomannan (GM) assay increased the sensitivity to 83.3%, increased the negative predictive value to 97.6%, and decreased the specificity to 69.8%. In most patients with IA, PCR-ELISA positivity anticipated or was simultaneous with the initiation of antifungal therapy, the abnormalities found by computed tomography, the mycological/histological diagnosis, and the GM positivity. Overall, 56.3% of the patients had at least 1 positive sample, and the false single-positive rate was 44.8%.

Conclusions: In addition to serial screening for GM antigenemia and radiological surveillance, PCR-ELISA may improve the rates of early diagnosis of IA and the management of patients with hematological malignancies.