Quantitation of cytomegalovirus DNA by real-time polymerase chain reaction in peripheral blood specimens of patients with solid organ transplants: Comparison with end-point PCR and pp65 antigen test

The polymerase chain reaction (PCR) for cytomegalovirus (CMV) DNA quantitation provides sensitive and specific data for detecting CMV as well as monitoring the infection and determining the appropriate antiviral strategy. A recently introduced real‐time PCR assay for CMV DNA quantitation was applied on 158 peripheral blood leukocytes (PBLs) from 32 liver‐transplanted patients with CMV asymptomatic infection and correlated with a commercial quantitative end‐point PCR (COBAS AMPLICOR CMV Monitor) and CMV pp65 antigenemia. A good correlation was found between real‐time PCR and pp65 antigen test (r2 = 0.691) and the two PCR assays (r2 = 0.761). Real‐time PCR data were higher in pre‐emptive treated patients (>20 pp65 + positive cells, median CMV DNA value: 3.8 log10 copies/500,000 PBLs) than in not‐treated ones (2.9 logs). According to pp65 levels of 0, 1–10, 11–20, 21–50, 51–100, and >100 positive cells/200,000 PBLs, median CMV DNA by real‐time PCR was 2.6, 3.0, 3.6, 4.0, 4.2, and 4.8 logs, respectively, (CMV DNA levels by COBAS AMPLICOR: 2.8, 2.9, 3.8, 3.7, 3.9, and 4.0 logs). For samples with >20 pp65 + cells, real‐time PCR gave significantly higher values than in groups with