DEFINITION OF CLINICAL THRESHOLD FOR CMV REAL-TIME PCR AFTER COMPARISON WITH PP65 ANTIGENAEMIA AND CLINICAL DATA

Abstract

Background: pp65 antigenaemia and real-time PCR are two methods that are used to diagnose CMV infection in its early stages and, thereby, to facilitate initiation of pre-emptive therapy.

Objectives: Firstly, to compare PCR with antigenaemia and clinical outcome in order to define a clinical threshold for starting pre-emptive therapy. Secondly, to study the impact of the transplant recipient’s serological status on the viral load and on the cut-offs.

Study Design: Sixty-two patients were analysed using antigenaemia (APAAP method) and real-time PCR. ROC curves were established with antigenaemia or clinical outcome as reference. Patients were divided into primo-infection or reactivation on the basis of the serological status.

Results: PCR correlated better with the clinical data (AUC closer to 1 and best sensitivity, PPV and NPV) than antigenaemia. Furthermore, the performance of qPCR was even better in the reactivation patients.

Conclusions: This work suggests that transplant recipients should be divided according to their serological status. Indeed, replacing antigenaemia by real-time PCR for decisions regarding initiation of pre-emptive therapy is of particular appeal in patients with positive serology. As a result of this work, we have set our clinical threshold at 1,500 copies/ml for reactivation.

Keywords:

• CMV
• PCR
• antigenaemia
• clinical data
• serological status

Keywords:

• Abbreviations used in the paper:
• HCMV: Human Cytomegalovirus
• NPV: Negative Predictive Value
• PPV: Positive Predictive Value
• AUC: Area Under the Curve
• ROC: Receiver-operating Characteristics
• qPCR: Quantitative Polymerase Chain Reaction
• SOT: Solid Organ Transplant
• BMT: Bone Marrow Transplant
• SCT: Stem Cell Transplant