Prospective Evaluation of a PCR-ELISA Assay for the Early Diagnosis of Invasive Aspergillosis (IA) in Hematological Patients

M. FLORENT1, M. CORNET 1, L. SANHES 1, V. LEVY 2, A. VEKHOFF 1, B. RIO 1, J. MARIE 1, A. BOUVET 1

Author address: 

1Hôtel-Dieu, Paris, France, 2St-Louis Hosp, Paris, France.

Abstract: 

Background: Detection of galactomannan (GM) by Platelia® Aspergillus (BioRad) assay is a sensitive and non-invasive method for IA diagnosis. However, two positive samples are required. We developed a PCR-ELISA assay to detect Aspergillus DNA in the serum. Methods: All the patients (pts) with hematological malignancies were enrolled in a one-year prospective study. They were screened twice weekly during the high-risk treatment periods for both the Platelia® Aspergillus assay and the PCR-ELISA assay, carried out on the same serum sample. QIAamp® DNA Mini kit (Qiagen) was used for DNA extraction. PCR assay was achieved using primers homolog to the 18S rRNA gene of A. fumigatus and A. flavus. Specific probe marked with digoxigenin was used to detect the amplicons by ELISA. Cases of IA were categorized as proven, probable and possible according to the EORTC/MSG criteria. Results: 644 sera from 125 pts were analysed. Underlying hematological malignancies were mainly acute leukemia (61%), multiple myeloma (15%) and lymphoma (15%). 62 pts were stem cell transplant recipients: 23 allogeneic and 39 autologous. IA was observed in 28 pts (4 proven, 7 probable and 17 possible). Sensitivity, specificity, positive and negative predictive values of the PCR-ELISA assay were 89 %, 65 %, 42 % and 95 %, respectively. Sensitivity was 100 % for proven or probable IA. PCR-ELISA was positive in 25 cases and the positivity preceded the IA diagnosis in 15 cases and the initiation of empirical antifungal therapy in 7 cases. GM detection was positive in 8 cases (³ 1 positive serum). 54 sera from 34 pts (27% of the 125 pts) were considered as false positive PCR-ELISA results (GM detection was negative for all sera). Conclusion: The PCR-ELISA assay is a sensitive method for IA diagnosis. Positive results should be interpreted in combination with the EORTC/MSG criteria. Its association with the GM detection could improve the early non-invasive diagnosis of IA.
2002

abstract No: 

M-907

Full conference title: 

42nd Interscience Conference on Antimicrobial Agents and Chemotherapy
    • ICAAC 42nd