Quantification du CMV : méthodes, intérêt, applications

Abstract

Cytomegalovirus (CMV) causes significant morbidity and mortality in immunocompromised individuals, whereas infection is often asymptomatic in immunocompetent patients. To identify patients at risk for CMV disease, several methods have been developed for viral quantitation in clinical samples. These methods are based on antigen detection or molecular biology. The pp65 quantitative antigenemia is a sensitive assay for estimating the viral load, but it has an important disadvantage : the need of rapid processing of the sample. For the molecular methods, several kits are available; they are based on hybridization (Murex Hybrid Capture ® System), Branched DNA (Quantiplex bDNA CMV Test ®), PCR (Cobas Amplicor CMV™ Monitor-Test) and NASBA. These kits give concordant results with antigenemia. The real-time PCR-based methods that have been recently developed, are now widely used for quantification of CMV viral load. These methods are rapid and avoid post-amplification contamination. Their major disadvantages are the cost of the PCR apparatus and the non-standardization of the assays. Utility of CMV viral load measurement for the follow-up of immunocompromised patients is now well-established. The choice of the best method for a laboratory depends on the type of patients, the number of samples received per day and the financial resources.