Cytomegalovirus infection in kidney transplant recipients: early diagnosis and monitoring of antiviral therapy by the antigenemia assay.

CYTOMEGALOVIRUS (CMV) is one of the most frequent infections in renal transplant recipients. After primary infection the virus remains dormant in various cells/organs for years. There are many factors that may reactivate virus replication; among them, organ transplantation certainly is the most important one, often causing serious disease and often associated with decreased graft survival. Though treatment is available, its timing and dosage should be tailored according to the ongoing CMV disease. There are different approaches for the diagnosis of CMV infections. The “gold standard” is cell culture in which the virus can be isolated. However, it is a timeconsuming and expensive procedure. Though combining virus isolation with immunofluorescence technique reduces the time from weeks to days, it is still not enough to meet the demand of a rapid diagnosis. Polymerase chain reaction (PCR) may have a strong impact on the diagnosis of CMV infection, but there is a need for further standardization and simplification. Many of the kidney transplant recipients fail to produce antibodies due to immunosuppressive therapy, making serological diagnosis undependable in CMV infections. Recently, detection of a specific CMV replication-related antigen (CMV antigen pp65) directly in leukocytes of patients has shown a good correlation with the clinical condition of the patient. This, CMV antigenemia assay (AA) seems to provide not only a reliable, specific, and sensitive diagnostic tool, but also facilitates monitoring the effectiveness of antiviral therapy.