Usefulness of DNA viral load quantification for cytomegalovirus disease monitoring in renal and pancreas/renal transplant recipients.

BACKGROUND: The purpose of this prospective study was to evaluate the usefulness of quantifying DNA-cytomegalovirus (CMV) load for the diagnosis and monitoring of CMV disease among renal and pancreas transplant patients under immunosuppressive drugs.
METHODS: A longitudinal study was conducted among 34 consecutive, unselected renal and pancreas/renal transplanted patients in our unit. During the first 3 posttransplant months, weekly monitoring of CMV infection and CMV disease was done, involving the determination of viremia by the shell vial assay, qualitative DNAemia by semi-nested polymerase chain reaction (PCR) and quantitative DNAemia by the hybrid capture system (HCS), a new and original hybridization method (337 samples were collected for each test). Qualitative and quantitative DNAemia results were blinded to physicians and three grades of disease were defined according to CMV related symptom occurrence.
RESULTS: PCR was the most sensitive (100%) but the least specific (78%) method for the diagnosis of CMV disease. HCS was specific for CMV genome detection, sensitive and reproducible. Blood DNA levels above 60 pg/ml were predictive of severe or moderate CMV disease (sensitivity, 92%; specificity, 100%). A significant decrease in viral load was observed after ganciclovir administration, and a positive PCR or HCS result at the end of the antiviral treatment was associated with relapse of CMV infection or disease.
CONCLUSIONS: It is concluded that quantitative DNAemia detection, with this new commercially available method, can predict disease and may be useful for a rational evaluation of ganciclovir preemptive therapy in such patients.