Quantification of cytomegalovirus viral load

Abstract

Cytomegalovirus (CMV), a member of the Herpesviridae family, is worldwide distributed. After the primary infection, CMV induces a latent infection with possible reactivation(s). It is responsible for severe to life-threatening diseases in immunocompromised patients and in foetuses and newborns of infected mothers. For monitoring CMV load, classical techniques based on rapid culture or pp65 antigenemia are progressively replaced by quantitative nuclear acid tests (QNAT), easier to implement and standardize. A large variety of QNAT are available from laboratory-developed assays to fully-automated commercial tests. The indications of CMV quantification include CMV infection during pregnancy and in newborns, and viral surveillance of grafted and non-grafted immunocompromised patients, patients with bowel inflammatory diseases and those hospitalised in intensive care unit. A close cooperation between virologists and clinicians is essential for optimizing the benefit of CMV DNA monitoring.

Keywords::

• congenital infection
• cytomegalovirus
• immunocompromised patients
• molecular biology
• quantitative nucleic acid test
• standardization

Financial & competing interests disclosure

S Pillet and B Pozzetto contributed to the evaluation of Argene/bioMérieux and Qiagen reagents [55,73] and received grants from these firms for laboratory material and travel expense. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Cytomegalovirus (CMV) is a wide-distributed infectious agent that induces a latent infection and can be responsible for severe diseases in immunocompromised patients and in fetuses and newborns of infected pregnant women.

• During the past 30 years, CMV quantification released mostly on the numbering of infected cells after urine or blood rapid culture and on pp65 antigenemia.

• Currently, quantitative nuclear acid tests (QNAT) are the standard of care for CMV monitoring in immunocompromised patients.

• Other clinical specimens than blood deserve special attention for CMV DNA quantification, including AF, urine and tissues.

• QNAT are available as either commercial assay, some of them being fully automated, or laboratory-developed tests. A standardization of results is urgently needed, despite the recent introduction of a calibrator.

• QNAT are warmly recommended in patients grafted with solid organs or bone marrow cells for monitoring preemptive antiviral treatment.

• CMV infection during pregnancy and in newborns is another major goal for CMV DNA monitoring.

• The other indications of CMV DNA monitoring include the surveillance of non-grafted immunocompromised patients (and notably AIDS patients), patients with bowel inflammatory diseases and patients hospitalized in intensive care unit (ICU).

• An excellent cooperation between virologists and clinicians is required for optimizing the benefit of CMV DNA monitoring for both defining the indications of tests and interpreting the results.