Use of the human cytomegalovirus (HCMV) antigenemia assay for diagnosis and monitoring of HCMV infections and detection of antiviral drug resistance in the immunocompromised

Background: Quantification of viral load in blood has proven to be helpful in the follow-up of disseminated HCMV infections in immunocompromised patients. Objectives: (i) To describe the antigenemia assay and its optimization and (ii) to analyze the use of the antigenemia assay for the diagnosis and monitoring of HCMV infections and for the detection of treatment failures. Study design: This article is intended to give an overview of our experience in the use of the antigenemia assay. Results and conclusions: In solid organ transplant recipients and patients with AIDS, HCMV symptomatic infections mostly appear when antigenemia values are > 300 pp65-positive PBL/2 x l0⁵ examined. To avoid the appearance of overt HCMV disease antiviral treatment could be administered when antigenemia levels are > 100 pp65-positive PBL/2 x l0⁵ examined. Bone marrow transplant recipients show symptomatic HCMV infections when antigenemia values are > 100 pp65- positive PBL/2 x 10⁵ examined. This group of patients should be treated when antigenemia levels are <10 pp65-positive PBL/2 x 10⁵ examined due to the higher mortality rate associated with HCMV complications. A decrease in antigenemia levels during therapy indicates a good response to antiviral drug, while stable or increasing values document a treatment failure and the emergence of drug-resistant HCMV strains.