Monitoring of Cytomegalovirus Infection in Solid-Organ Transplant Recipients by an Ultrasensitive Plasma PCR Assay

Abstract

Early and accurate monitoring of cytomegalovirus (CMV) infection in solid-organ transplant recipients is of major importance. We have assessed the potential benefit of an ultrasensitive plasma-based PCR assay for renal transplant recipients. The pp65 CMV antigen (pp65 Ag) assay using leukocytes was employed as a routine test for the monitoring of CMV in 23 transplant recipients. We compared the pp65 antigenemia with the CMV load quantified by an ultrasensitive PCR (US-PCR) with a limit of detection of 20 CMV DNA copies/ml of plasma. CMV infection was detected in 215 (67%) of 321 plasma samples by the US-PCR compared with 124 (39%) of 321 samples by the pp65 Ag assay. The US-PCR assay permitted the detection of CMV infection episodes following transplantation a median of 12 days earlier than the pp65 Ag assay. Moreover, during CMV infection episodes, DNA detection by the US-PCR was consistently positive, whereas false negative results were frequently observed with the pp65 Ag assay. We found a good correlation between the two assays, and the peak viral loads were significantly higher in patients with CMV-related complications (median, 5,000 DNA copies/ml) than in those without symptoms (1,160 DNA copies/ml) (P ‫؍‬ 0.048). In addition, patients that did not require preemptive therapy based on the results of the pp65 assay had CMV loads significantly lower (median, 36 DNA copies/ml) than those that needed treatment (median, 4,703 DNA copies/ml) (P < 0.001). These observations provided cutoff levels that could be applied in clinical practice. The ultrasensitive plasmabased PCR detected CMV infection episodes earlier and provided more consistent results than the pp65 Ag assay. This test could improve the monitoring of CMV infection or reactivation in renal transplant recipients.

Clinically‐based determination of safe DNAemia cutoff levels for preemptive therapy or human cytomegalovirus infections in solid organ and hematopoietic stem cell transplant recipients

“…In our study, the levels of viral DNAemia were those actually detected prior to the start of preemptive therapy, which prevented consistently HCMV disease and, thus, were verified as safe clinically. Cutoffs proposed by another group taking care of the patient clinical outcome were more similar to those calculated in the present study [Hadaya et al, 2003].…”

Clinical Utility of Viral Load in Management of Cytomegalovirus Infection after Solid Organ Transplantation

“…Other studies, however, have reported a significantly lower sensitivity of antigenemia testing than those of molecular tests (80,88,(94)(95)(96)(97)(98)(99). In one study, the sensitivity of pp65 antigenemia was lower (39%) than that of an ultrasensitive PCR-based assay performed on plasma (67%) (96). Moreover, the LDT plasma PCR assay detected CMV infection 12 days earlier than the antigenemia test (96).…”

“…One of these studies reported a strong correlation between pp65 antigenemia and CMV PCR performed on whole-blood specimens by use of an in-house laboratory-developed test (LDT) (91). Other studies, however, have reported a significantly lower sensitivity of antigenemia testing than those of molecular tests (80,88,(94)(95)(96)(97)(98)(99). In one study, the sensitivity of pp65 antigenemia was lower (39%) than that of an ultrasensitive PCR-based assay performed on plasma (67%) (96).…”

“…In one study, the sensitivity of pp65 antigenemia was lower (39%) than that of an ultrasensitive PCR-based assay performed on plasma (67%) (96). Moreover, the LDT plasma PCR assay detected CMV infection 12 days earlier than the antigenemia test (96). Another study reported a significantly lower sensitivity (26%) of pp65 antigenemia testing than those of two PCR-based assays (COBAS Amplicor CMV Monitor test [48.6%] and an inhouse LDT [performed on a LightCycler] [54%]) (98).…”

Pretransplantation CMV-specific T cells protect recipients of T-cell-depleted grafts against CMV-related complications

“…Both methods have been previously described. 18,19 Preemptive ganciclovir therapy was given at a dose of 5 mg/kg intravenously twice a day for 14 days and then 5 mg/kg daily for 2 weeks. In patients with neutropenia, foscarnet at a dose 90 mg/kg intravenously twice a day for 2 weeks and then 90 mg/kg daily 2 weeks was used.…”