MONITORING OF LEUKOCYTE CYTOMEGALOVIRUS DNA IN BONE-MARROW TRANSPLANTRECIPIENTS BY NESTED PCR

A nested PCR assay for the detection of human cytomegalovirus (CMV) DN A was evaluated by weekly monitoring of blood samples taken from 101 b one marrow transplant (BMT) recipients, When peripheral blood leukocyt es were used as the source of CMV DNA, even a modified assay with stri ngent temperature-cycling conditions was as sensitive as the standard assay, The sensitivity, specificity, and positive predictive value of two consecutively positive leukocytic PCR results with this modified a ssay in predicting CMV disease of 101 patients submitting 1,441 periph eral blood leukocyte samples were found to be 92.1, 63.5, and 60.3%, r espectively. The positive predictive value of patients' seropositivity for CMV was 40%, while that of viremia was 72%. However, viremia foll owed CMV disease by a median of 1.5 days, while the first leukocytic p ositive PCR assay preceded disease by a median of 14 days, By use of t he criteria of two consecutively positive PCR results instead of recip ient CMV seropositivity for starting preemptive ganciclovir treatment, 38 of the 43 recipients with isolated single positive or negative ass ays (groups I and II) would be spared unnecessary ganciclovir treatmen t, Moreover, two other findings support the use of antiviral prophylax is before engraftment in high-risk cases and subsequent preemptive tre atment of patients with two consecutively positive PCR assays, First, for 7.9% of 76 patients with positive assays (groups II and III), the first positive PCR assay occurred before engraftment, which implied th e presence of viral DNA in the blood (DNAemia) soon after transplantat ion. Second, isolated single positive assays which were clustered arou nd the second to sixth weeks after transplantation were found for 18 p atients (group II) and could represent abortive episodes of CMV infect ion.