Mesure et interprétation des charges virales dans les infections à herpèsvirus humains (cytomégalovirus, virus Epstein-Barr, herpèsvirus humains 6 et 8)

Measuring the viral load has provided a significant advance in the pathophysiological understanding, diagnosis and therapeutic monitoring of cytomegalovirus, Epstein-Barr virus, human herpesvirus 6, and human herpesvirus 8 infections. The methods of quantitative PCR, especially real-time PCR, have made the quantification of DNA genome sensitive, reproducible, accessible and applicable to numerous biological matrices, among which whole blood, plasma and cerebrospinal fluid. However improvements are still required, in terms of standardization of techniques and disposal of internationally recognized quantification standards. It is also needed to clarify and homogenize the criteria for interpreting viral load values regarding the diagnosis of active infections, prediction of occurrence of associated diseases, indications of antiviral treatments and monitoring of their effectiveness. The measurement of viral load cytomegalovirus has now become an essential element in the monitoring of immunocompromised patients. Regarding Epstein-Barr virus, the viral load is used to anticipate the occurrence of associated lymphoproliferations while the viral load HHV-8 has still not perfectly specified indications in the diagnosis of associated malignancies, the first of which being Kaposi's sarcoma. Besides the possibility of an intense viral reactivation, very high values of viral load in the case of human herpesvirus 6 should evoke a chromosomal integration of viral DNA, specific to this virus and observed in about 1% of the general population.