Differences in cytomegalovirus replication quantified using quantitative polymerase chain reaction and antigenemia after allogeneic stem cell transplantation.

Fifty percent of allogeneic stem cell recipients develop cytomegalovirus (CMV) infection in the first 100 days posttransplantation. Various methods have been used to determine CMV infections, including antigenemia assay and real-time polymerase chain reaction (RT-PCR). Although antigenemia assay has been used more frequently, this technique is less sensitive than RT-PCR. In contrast, RT-PCR has a low positive predictive value for CMV end-organ disease. Cytomegalovirus infections were analyzed in 41 peripheral blood samples from allogeneic stem cell recipients using both antigenemia assay and RT-PCR; results were discordant in 36.6% of patients. Although the antigenemia assay detected CMV replication in 29.2% of cases, RT-PCR was positive in 65.8%. In 83.3% of patients, results detected using the antigenemia assay were delayed by a median (range) of 5 (2-20) weeks compared with positive RT-PCR results. Within the first 100 days posttransplantation, higher levels of viral replication measured using RT-PCR were observed in patients with vs without antigenemia. In addition, in patients with antigenemia, viral load was significantly higher before day 100 than after (P=.01 and P=.008, respectively) compared with those without antigenemia.