Monitoring of cytomegalovirus reactivation in bone marrow transplant recipients by real-time PCR.

Cytomegalovirus (CMV) has been recognized as the most important viral pathogen in persons undergoing bone marrow transplantation (BMT). The aim was to develop a quantitative PCR assay to quantify CMV DNA in peripheral blood leukocytes (PBLs) of bone marrow transplantation (BMT) patients. An in-house real-time PCR assay based on TaqMan technology was developed to monitor the quantity of CMV DNA in PBLs of the BMT recipients. Sequential blood samples (415 specimens) were collected from 43 patients as weekly intervals until day 100 after transplantation. The CMV DNA was quantified in parallel with the pp65 antigenemia assay in PBL samples. Viral reactivation occurred in 51% and 41.8% of the recipients as detected by RQ-PCR and antigenemia assays respectively. There was a significant correlation between both assays (P < 0.0001); however, the RQ-PCR was more sensitive than the antigenemia. CMV DNA was detected by the RQ-PCR by a median of 14 days earlier than the antigenemia. Preemptive therapy was implemented in the antigenemia positive cases. The administration of ganciclovir led to a rapid decrease in the viral load. After preemptive therapy, the antigenemia achieved a negative result earlier than the RQ-PCR assay (a median of 17.5 days). An increase of viral load in both quantitative assays and of cyclosporine serum level were identified as the most significant risk factors for CMV reactivation. The quantitative CMV PCR might be a useful tool for monitoring the CMV reactivation and guiding the efficacy of the CMV preemptive therapy in BMT recipients.