ABSTRACT
To establish a sensitive and specific real time PCR for quantitation of cytomegalovirus [CMV] DNA in clinical specimens. In a prospective study, CMV DNA was quantified in blood samples of 255 kidney recipients with and without CMV-related symptoms between the years 2000 and 2005 in Kuwait. In a selected group of patients, the effect of anti-CMV chemotherapy was monitored by quantitative real time PCR [qRT-PCR]. The established qRT-PCR assay had a sensitivity to detect 30 CMV DNA copies. CMV DNA was detected in 54/255 [24%] patients; of these, 17 [31.5%] were asymptomatic, and 37 patients [68.5%] had symptomatic CMV infection. Sequential blood specimens were collected from all CMV-positive patients and tested by CMV pp65 antigenemia and qRT-PCR assays. There was a moderate positive correlation between the two assays [Pearson's correlation=0.52]. The median CMV viral load measured by qRT-PCR was higher in symptomatic [6.5 +/- 10.4 copies/ml] than in asymptomatic [185 copies/ml] patients [p=0.001]. The estimated cut-off value of CMV DNA for CMV symptoms/disease was 6 800 copies/ml of blood. Testing of sequential samples from patients treated with symptomatic CMV infection showed that the viral load was significantly reduced after 3 weeks of anti-CMV chemotherapy [p=0.001]. The reported qRT-PCR is a sensitive method for quantitation of CMV DNA in the blood of kidney recipients and can be useful in monitoring the efficacy of anti-CMV therapy