Plasma Cytomegalovirus DNA Research Articles

Quantitation of human cytomegalovirus DNA in plasma using an affordable in-house qPCR assay

Quantitation of human cytomegalovirus (HCMV) DNA is used to monitor immunocompromised patients in order to identify patients for preemptive therapy. Although several commercial qPCR assays are available for quantitation of HCMV, their major disadvantage is the high cost. In the present study, an internally controlled quantitative real-time PCR assay based on hydrolysis probe technology was developed for detection and quantitation of HCMV DNA in plasma samples. To demonstrate its performance characteristics, a total of 178 plasma samples from 102 kidney and hematopoietic stem cell transplanted patients were tested. The assay showed good precision and reproducibility, and an analytical sensitivity of 288.5 copies/ml or 17.6 copies/reaction. A sensitivity of 93.1% and a specificity of 96.6% were determined by examining clinical samples. Analysis of a panel containing potentially interfering viruses demonstrated no cross-reactivity with the assay. A strong correlation was observed between this qPCR method and the commercial Artus(®) CMV RG PCR kit (R=0.948; P=0.000). These results indicate that the affordable internally controlled qPCR method described will be useful for monitoring HCMV infection in plasma samples of immunocompromised patients.

Prevalence of congenital cytomegalovirus infection in Slovenia: A study on 2,841 newborns

Human cytomegalovirus (CMV) is the most frequent cause of congenital infection in humans. In the first prevalence study of congenital CMV infection in Eastern and Central Europe, all neonates born in a 22-month period in two Slovenian maternity units (total of 2,841 newborns) were screened prospectively for congenital CMV infection by a real-time polymerase chain reaction (PCR) in urine. In all newborns with positive screening results, plasma and dried blood spots (DBS) collected at birth were tested additionally for CMV DNA. Congenital CMV infection was confirmed by virus isolation from a urine sample collected within the first 2 weeks of life. Congenital CMV infection was identified in four out of 2,841 newborns tested (incidence 0.14%; 95% CI, 0.05-0.39%). In four newborns with confirmed congenital infection, the concentration of CMV DNA in urine ranged from 4.68 to 8.18 log(10) copies/ml, all four newborns had detectable CMV DNA in plasma taken at birth (1.26-3.34 log(10) copies/ml) and two out of four had detectable CMV DNA in DBS collected during newborn metabolic screening. None of the four newborns with confirmed congenital CMV infection was symptomatic. The study showed that the prevalence of congenital CMV infection at birth in Slovenia is among the lowest in the world and that CMV DNA PCR testing of urine is a suitable and affordable real-time screening strategy for congenital CMV infection. If it is performed in 24 mini-pools, the cost of screening is 1.4 €/newborn and the cost of detecting a single newborn with congenital CMV infection 1,000 €.

Cytomegalovirus DNA stability in EDTA anti-coagulated whole blood and plasma samples

Background Cytomegalovirus (CMV) DNA viral load testing is routinely performed in centers that serve patients that are immunosuppressed from organ or hematopoietic stem cell transplantation. Clinical laboratories that offer this testing often face practical concerns about the storage of these specimens to ensure accurate measurement for patient care. The published studies that assess CMV DNA stability at 4 °C have done so only up to 72 h. Objective Our objective was to determine the stability of CMV DNA in whole blood and plasma for clinical viral load testing over a 14 day period. Study design Twenty-one plasma samples that were CMV-positive and twenty whole blood samples (including eleven CMV-negative whole blood samples spiked with CMV-positive plasma) were stored at 4 °C and underwent extraction and amplification at 3 time points: Day 0, Day 7, and Day 14. Results Log 10 values were calculated and t-test was performed on the values comparing Day 0 to Day 14 for plasma and whole blood. There was no statistically significant difference between Day 0 and Day 14 for both specimen types, including the CMV-negative whole blood specimens that were spiked with CMV-positive plasma. Conclusions CMV DNA in plasma and whole blood is stable for 14 days at a temperature of 4 °C.

Immunological Monitoring for Guidance of Preemptive Antiviral Therapy for Active Cytomegalovirus Infection in Allogeneic Stem-Cell Transplant Recipients: A Pilot Experience

Immunological Monitoring for Guidance of Preemptive Antiviral Therapy for Active Cytomegalovirus Infection in Allogeneic Stem-Cell Transplant Recipients: A Pilot Experience

Cytomegalovirus viraemia in the modern antiretroviral era*

Cytomegalovirus viraemia in the modern antiretroviral era*

Comparative Evaluation of Three Automated Systems for DNA Extraction in Conjunction with Three Commercially Available Real-Time PCR Assays for Quantitation of Plasma Cytomegalovirus DNAemia in Allogeneic Stem Cell Transplant Recipients

Limited data are available on the performance of different automated extraction platforms and commercially available quantitative real-time PCR (QRT-PCR) methods for the quantitation of cytomegalovirus (CMV) DNA in plasma. We compared the performance characteristics of the Abbott mSample preparation system DNA kit on the m24 SP instrument (Abbott), the High Pure viral nucleic acid kit on the COBAS AmpliPrep system (Roche), and the EZ1 Virus 2.0 kit on the BioRobot EZ1 extraction platform (Qiagen) coupled with the Abbott CMV PCR kit, the LightCycler CMV Quant kit (Roche), and the Q-CMV complete kit (Nanogen), for both plasma specimens from allogeneic stem cell transplant (Allo-SCT) recipients (n = 42) and the OptiQuant CMV DNA panel (AcroMetrix). The EZ1 system displayed the highest extraction efficiency over a wide range of CMV plasma DNA loads, followed by the m24 and the AmpliPrep methods. The Nanogen PCR assay yielded higher mean CMV plasma DNA values than the Abbott and the Roche PCR assays, regardless of the platform used for DNA extraction. Overall, the effects of the extraction method and the QRT-PCR used on CMV plasma DNA load measurements were less pronounced for specimens with high CMV DNA content (>10,000 copies/ml). The performance characteristics of the extraction methods and QRT-PCR assays evaluated herein for clinical samples were extensible at cell-based standards from AcroMetrix. In conclusion, different automated systems are not equally efficient for CMV DNA extraction from plasma specimens, and the plasma CMV DNA loads measured by commercially available QRT-PCRs can differ significantly. The above findings should be taken into consideration for the establishment of cutoff values for the initiation or cessation of preemptive antiviral therapies and for the interpretation of data from clinical studies in the Allo-SCT setting.

Valganciclovir Reduces T Cell Activation in HIV-Infected Individuals With Incomplete CD4+ T Cell Recovery on Antiretroviral Therapy

Elevated immune activation persists during treated human immunodeficiency virus (HIV) infection and is associated with blunted CD4 recovery and premature mortality, but its causes remain incompletely characterized. We hypothesized that asymptomatic cytomegalovirus (CMV) replication might contribute to immune activation in this setting. Thirty antiretroviral therapy-treated HIV-infected CMV-seropositive participants with CD4 counts <350 cells/mm(3) were randomized to receive valganciclovir 900 mg daily or placebo for 8 weeks, followed by an additional 4-week observation period. The primary outcome was the week 8 change in percentage of activated (CD38(+) HLA-DR(+)) CD8(+) T cells. Fourteen participants were randomized to valganciclovir and 16 to placebo. Most participants (21 [70%] of 30) had plasma HIV RNA levels <75 copies/mL. The median CD4 count was 190 (IQR: 134-232) cells/mm(3), and 12 (40%) of 30 had detectable CMV DNA in saliva, plasma, or semen at baseline. CMV DNA continued to be detectable at weeks 4-12 in 7 (44%) of 16 placebo-treated participants, but in none of the valganciclovir-treated participants (P = .007). Valganciclovir-treated participants had significantly greater reductions in CD8 activation at weeks 8 (P = .03) and 12 (P = .02) than did placebo-treated participants. These trends were significant even among those with undetectable plasma HIV RNA levels. CMV (and/or other herpesvirus) replication is a significant cause of immune activation in HIV-infected individuals with incomplete antiretroviral therapy-mediated CD4(+) T cell recovery. NCT00264290.

Maribavir prophylaxis for prevention of cytomegalovirus disease in recipients of allogeneic stem-cell transplants: a phase 3, double-blind, placebo-controlled, randomised trial

Available drugs against cytomegalovirus have adverse effects that compromise their prophylactic use in recipients of allogeneic stem-cell transplants. We assessed the safety, tolerability, and antiviral activity of oral maribavir in such patients. In this placebo-controlled, randomised, double-blind, multicentre phase 3 study, we enrolled adult patients recipient-seropositive or donor-seropositive for cytomegalovirus who had undergone allogeneic stem-cell transplantation. Patients were recruited from 90 centres in Canada, Europe, and the USA. After engraftment, patients were stratified by recipient cytomegalovirus serostatus and conditioning regimen (myeloablative or reduced-intensity) and assigned (2:1) by masked computer-generated randomisation sequence to receive maribavir 100 mg twice daily or placebo for up to 12 weeks, with weekly blood cytomegalovirus surveillance. If the virus was detected, administration of study drug was stopped and pre-emptive anticytomegalovirus treatment started. The primary endpoint was cytomegalovirus disease within 6 months of transplantation. Analysis was by intention-to-treat. This study is registered with ClinicalTrials.gov, NCT00411645. Between December, 2006, and May, 2008, 681 patients were enrolled and assigned to receive maribavir (454) or placebo (227). The incidence of cytomegalovirus disease within 6 months was 20 of 454 (4%) for the maribavir group and 11 of 227 (5%) for the placebo group (OR 0.90; 95% CI 0.42-1.92). During the 100 days following transplantation, cytomegalovirus infection rates as measured by pp65 antigenaemia were lower in the maribavir group (26.4%) than in the placebo group (34.8%; OR 0.67; 0.47-0.95), but not when measured by plasma cytomegalovirus DNA PCR (27.8%vs 30.4%; OR 0·88; 0.62-1.25), nor by initiation of treatment against cytomegalovirus (30.6%vs 37.4%; OR 0.73, 0.52-1.03). Maribavir was well tolerated: most adverse events, including incident acute graft-versus-host disease and neutropenia, affected both groups equally, except for taste disturbance (15% maribavir, 6% placebo). Compared with placebo, maribavir prophylaxis did not prevent cytomegalovirus disease when started after engraftment. Cytomegalovirus disease as a primary endpoint might not be sufficient to show improvements in cytomegalovirus prevention in recipients of allogeneic stem-cell transplants in the setting of pre-emptive antiviral treatment. Clinical and virological composite endpoints should be used in future trials. ViroPharma Incorporated.

High incidence of cytomegalovirus, human herpesvirus-6, and Epstein-Barr virus reactivation in patients receiving cytotoxic chemotherapy for Adult T cell leukemia

The etiology of cytomegalovirus (CMV), human herpesvirus-6 (HHV-6), and Epstein-Barr virus (EBV) reactivation and the potential for complications following cytotoxic chemotherapy in the absence of allogeneic transplantation are not clearly understood. Patients with adult T cell leukemia (ATL) are susceptible to opportunistic infections. In this study, the incidence, kinetics and clinical significance of reactivation of CMV, HHV-6, and EBV in ATL patients were investigated. Viral DNA in a total of 468 plasma samples from 34 patients was quantified using real-time PCR. The probability of CMV, HHV-6, and EBV reactivation by 100 days after the start of chemotherapy was 50.6%, 52.3%, and 21.6%, respectively. Although most CMV reactivations were self-limited, plasma CMV DNA tended to persist or increase if the CMV DNA levels in plasma reached ≥ 10(4) copies/ml. CMV reactivation was negatively associated with survival, but the P-value for this association was near the borderline of statistical significance (P=0.052). One patient developed fatal interstitial pneumonia concomitant with peak CMV DNA accumulation (1.6 × 10(6) copies/ml plasma). Most HHV-6 and EBV reactivations were self-limited, and no disease resulting from HHV-6 or EBV was confirmed. HHV-6 and EBV reactivation were not associated with reduced survival (P=0.35 and 0.11, respectively). These findings demonstrated that subclinical reactivation of CMV, HHV-6, and EBV were common in ATL patients receiving chemotherapy. There were differences in the viral reactivation patterns among the three viruses. A CMV load ≥ 10(4) copies/ml plasma was indicative of subsequent exacerbation of CMV reactivation and developing serious clinical course.

The natural course of primary cytomegalovirus infection in blood donors

As cytomegalovirus (CMV) DNA is frequently detectable in the plasma of recently infected sero-positive blood donors, information concerning primary CMV infection is important for the identification of possibly infectious donors. Monitoring of 17 982 donors for CMV antibodies and DNA in plasma identified 14 subjects with ongoing primary CMV infection. Thirteen donors were interrogated for possible sources of infection and CMV-related symptoms, and monitored for CMV antigens, CMV DNA in plasma, leucocytes and urine, course of IgG and IgM antibodies as well as markers of systemic infection and parameters of organ function. CMV antigens and DNA were detectable in peripheral blood for up to 54 and 269 days respectively. Clearance of CMV DNA from blood correlated with clearance of IgM antibodies, development of IgG antibodies against the membrane glycoprotein gB and development of high avidity IgG antibodies. Eighty-five percent of subjects with primary CMV infection, but even 69% of matched controls reported possibly CMV-related symptoms. Sixty-two and 23%, respectively, had contact with possible sources of infection. One donor developed a febrile illness accompanied by increased levels of CMV DNA in peripheral blood 2 to 3 weeks after seroconversion. In other donors, neither markers of systemic infection nor parameters of organ function correlated with the course of CMV DNA and antigens. Potentially infectious donors can be identified by measuring CMV DNA, IgM antibodies or avidity of IgG antibodies. Alternatively, blood products donated during the first year after seroconversion should not be used for immunocompromised patients.

Primary cytomegalovirus infectious colitis complicating Crohn's disease successfully treated with oral valganciclovir

Most cases of cytomegalovirus (CMV) colitis that develop in patients with inflammatory bowel disease (IBD) are caused by reactivation of a latent virus. Primary CMV infections are rare in adult patients. Treatment with immunosuppressive agents increases the infection risk in patients with IBD. We present a 26 year old lady with primary CMV colitis, superimposed on underlying Crohn's colitis. The diagnosis was confirmed by a viral-like prodrome, a positive CMV IgM titer, presence of low avidity IgG antibodies to CMV, high CMV DNA titers in the plasma, and immunohistological detection of CMV positive cells in her colonic mucosa. The patient responded to initial treatment with intravenous ganciclovir with a fall in plasma levels of CMV DNA, treatment was completed with oral valganciclovir until plasma CMV DNA levels became undetectable.

Cytomegalovirus DNA Load Patterns Developing After Lung Transplantation Are Significantly Correlated With Long-Term Patient Survival

Cytomegalovirus (CMV) causes complications after lung transplantation (LuTX). We have investigated whether patient survival is associated with CMV DNA load patterns developing in EDTA-plasma and bronchoalveolar lavage (BAL) during the first year after LuTX and whether patients' predispositions influence this development. CMV DNA loads in plasma and BAL were investigated serially in 84 LuTX recipients. Various patient characteristics and variants in mannose-binding lectin and toll-like receptor 2 genes were analyzed. Patient survival beyond 1 year posttransplantation and influence of patient-specific factors on viral load development were assessed by Kaplan-Meier survival and Cox regression methods. Four distinct group patterns were observed: (a) less than 1000 copies CMV DNA/mL in plasma and BAL (42%); (b) more than 1000 copies/mL in BAL only (21%); (c) one limited episode (25%), or (d) more than one episode of more than 1000 copies/mL plasma (12%). The risk of death after the first year was elevated 14-fold in group D and sixfold in group B. CMV DNA load patterns were not associated with patient-specific factors except CMV-D+/R- status. Initial and peak plasma CMV DNA levels were significantly increased in group D. Active CMV replication that is not limited after one episode of CMV DNAemia leads to significantly decreased long-term survival after LuTX.

Low Rate of CMV End-Organ Disease in HIV-Infected Patients Despite Low CD4+ Cell Counts and CMV Viremia: Results of ACTG Protocol A5030

Purpose: To describe cytomegalovirus (CMV) end-organ disease (EOD) rate in AIDS patients with low CD4+ cell count despite HAART who were enrolled in a randomized, placebo-controlled trial of preemptive valganciclovir (VGCV) to prevent CMV EOD in those with CMV viremia. Methods: Subjects (N = 338) were HIV-infected with CD4+ count <100 cells/mm3, plasma HIV RNA >400 copies/mL, and on stable or no HAART. All underwent plasma CMV DNA PCR testing every 8 weeks (Step 1); those with detectable CMV DNA were randomized to VGCV or placebo (Step 2). Results: Plasma CMV DNA was detected in 68 (20%), of whom 4 developed CMV EOD. During Step 1, 53 died. Of the 47 who entered Step 2 (24 VGCV, 23 placebo), CMV EOD was diagnosed in 10 (4 VGCV, 6 placebo) and 15 died (7 VGCV, 8 placebo). Of those randomized to placebo, 14% were diagnosed with CMV EOD at 12 months. Conclusions: We observed a lower CMV EOD rate among subjects receiving HAART than predicted based on published literature. However, mortality was high in this study. Our findings suggest that preemptive anti-CMV therapy in patients with persistently low CD4+ cell counts in the current treatment era may not be warranted given the low incidence of CMV EOD and high all-cause mortality observed in this study population.

The Effect of Single and Combined Activating Killer Immunoglobulin-like Receptor Genotypes on Cytomegalovirus Infection and Immunity after Hematopoietic Cell Transplantation

It has been shown that activating killer Ig-like receptor (aKIR) genes are important for control of cytomegalovirus (CMV) reactivation after hematopoietic cell transplantation (HCT). To date, using the broad classification of KIR haplotypes A and B, the precise role of individual KIR genes in the control of infection cannot be discerned. To address this, a consecutive case series of 211 non-T cell-depleted HCT patients all at risk for CMV were monitored biweekly for CMV DNA in plasma by quantitative polymerase chain reaction (Q-PCR) and at intervals for CMV-specific T cell immunity. Comparing patients with CMV reactivation (n = 152) to those with no reactivation (n = 59), the presence of specific aKIR haplotypes in the donor, but not in the recipient, were associated with protection from CMV reactivation and control of peak plasma CMV DNA ( P < .001). A donor aKIR profile, predictive for low risk of CMV reactivation, contained either aKIR2DS2 and aKIR2DS4 or had ≥5 aKIR genes. Neither donor nor recipient inhibitory KIR (iKIR) played a role in a protective effect. CD4 +- and CD8 +-specific CMV immunity did not explain reduced CMV infection. The initial control of CMV infection after HCT is managed by aKIR functions, and donor aKIR haplotypes deserve further evaluation in donor selection for optimized HCT outcome.

Cytomegalovirus DNA Measurement in Blood and Plasma Using Roche LightCycler CMV Quantification Reagents

Cytomegalovirus (CMV) is a common cause of morbidity and mortality in immunosuppressed patients. Newly available commercial systems facilitate the measurement of CMV DNA in whole blood or plasma, as a means of detecting and monitoring active disease. We evaluated the performance characteristics of a quantitative polymerase chain reaction that relies on analyte-specific reagents and instruments from Roche Diagnostics. DNA was extracted using a MagNaPure instrument from blood and matched plasma specimens of patients with active CMV disease (defined by another molecular assay) and from controls. Viral load was measured against Roche's standards on a LightCycler instrument, followed by melt curve analysis to confirm product specificity. Dual hybridization probes targeted the CMV UL54 gene and a control sequence that was spiked before extraction. Accuracy and linearity were established using spiked DNA from the Towne-strain CMV. The assay was linear across 6 logs, and it detected CMV DNA in 67/70 blood samples (96%) from patients who were considered to have an active CMV infection, including all 67 viral loads above 208 CMV copies/mL, suggesting that it was sensitive enough to detect clinically significant infections in immunosuppressed patients. Virus levels in plasma correlated reasonably well with the levels in whole blood (r=0.5756), suggesting that levels in either plasma or blood level were indicative of active infection. It was important to verify the calculated values by visualizing the amplification plot and using the melt curve analysis to resolve discrepancies. The LightCycler CMV assay is rapid, sensitive, and linear for quantifying CMV viral load, and it seems to be useful in the diagnosis and monitoring of affected patients.

Cytomegalovirus Colitis in a Critically Ill Patient following Elective Repair of an Abdominal Aortic Aneurysm

We describe a case of cytomegalovirus colitis in a critically ill but otherwise immunocompetent 61-year-old male. Infection was demonstrated by histology and confirmed by plasma polymerase chain reaction and detection of cytomegalovirus IgM antibody. The patient was treated with ganciclovir with resolution of the cytomegalovirus viraemia. Cytomegalovirus colitis may be an under-recognised problem in immunocompetent patients who are critically ill. Quantification of plasma cytomegalovirus DNA by polymerase chain reaction is a non-invasive method of supporting the diagnosis and can be used to monitor the treatment of cytomegalovirus infection in the immunocompetent.

High prevalence of cytomegalovirus DNA in plasma samples of blood donors in connection with seroconversion

Human cytomegalovirus (CMV) is considered to latently infect blood cells. Transfusion-transmitted infection (TT-CMV) of immunocompromised patients occurs despite the use of CMV-seronegative or leukoreduced units. The prevalence of CMV DNA in plasma was investigated in 82 blood donors who had previously been seronegative for CMV and showed anti-CMV immunoglobulin G for the first time, 598 blood donors who were seropositive for at least 1 year, and 150 seronegative blood donors. In a second part of the study, the overall prevalence of CMV DNA in blood donations was assessed based on 31,745 donations. CMV DNA was repeatedly detected in plasma samples of 44 percent of newly seropositive donors (12%-62%, depending on the interval to the last seronegative donation). All steadily seropositive or seronegative donors were negative for the presence of CMV DNA. Detection of CMV DNA in connection with seroconversion was accompanied by significantly increased neopterin, increased alanine aminotransferase, and reduced white blood cell counts, but the sensitivity of these surrogate markers was only 71 percent. The overall prevalence of CMV DNA in blood products due to primary CMV infection of donors was at least 0.13 percent. Viremia of newly seropositive donors may be an important reason for the residual risk of TT-CMV despite leukoreduction. Furthermore, transfusion of WBC-reduced blood components from seronegative donors could imply a greater risk of TT-CMV than transfusion of WBC-reduced blood from donors who have been seropositive for at least 1 year, because window-phase donations but no reactivation could be detected in this study.

Comparable incidence and severity of cytomegalovirus infections following T cell-depleted allogeneic stem cell transplantation preceded by reduced intensity or myeloablative conditioning

Reports on infectious complications following reduced intensity conditioning (RIC) before allogeneic stem cell transplantation (allo-SCT) are equivocal. This prospective follow-up study compared the impact of cytomegalovirus (CMV) infections following RIC with fludarabine, ATG and busulphan or conventional myeloablative conditioning (MAC). Forty-eight RIC and 59 MAC patients were enrolled. The occurrence and severity of CMV infections within 100 days following allo-SCT were assessed, using plasma CMV DNA load kinetics. CMV DNAemia was observed in 21 RIC (60%) and in 19 MAC (44%) patients at risk for CMV. The mean CMV DNAemia free survival time was comparable following RIC and MAC: 70 days (95% (confidence interval) CI: 59-80 days) and 77 days (95% CI: 68-86 days), respectively (P=0.24). Parameters indicative for the level of CMV reactivation, including the area under the curve of CMV DNA load over time as well as the onset, the peak values and duration of CMV infection episodes, the numbers and duration of CMV treatment episodes and recurrent infections, were not different in both groups. During follow-up, none of the patients developed CMV disease. RIC with fludarabine, ATG and busulphan demonstrated safety comparable to conventional MAC with regard to frequency and severity of CMV infections within 100 days following T cell-depleted allo-SCT.

Prophylaxis Against Cytomegalovirus Infections with Oral Maribavir in Allogeneic Stem Cell Transplant Recipients: Results of a Randomized, Double-Blind, Placebo-Controlled Trial.

Cytomegalovirus (CMV) remains a major threat to recipients of allogeneic stem cell transplants (SCT). Potential toxicities of currently available anti-CMV agents complicate their use in this population. Maribavir (MBV) is an oral antiviral drug with a unique mechanism of action against CMV and a promising safety profile in early clinical studies. This randomized, double-blind, multicenter, dose-ranging study enrolled adult CMV-seropositive recipients of allogeneic SCT. After engraftment, patients were randomized to receive CMV prophylaxis with placebo or MBV at one of three doses for up to 12 weeks. CMV surveillance was performed weekly with both CMV pp65 antigenemia and plasma CMV DNA PCR assays. If CMV was detected, study drug was stopped and preemptive anti-CMV therapy started as per standard practice at each center. A total of 111 patients were enrolled (median age 47 years; 70% myeloablative SCT; 53% related donor). Incidence of CMV infection or disease in the first 100 days post-SCT are shown in the table. The safety profile of maribavir was favorable in this patient population; most adverse events occurred at similar rates in placebo and MBV groups. There was no adverse impact of MBV on neutrophil counts or other laboratory or ECG parameters. Consistent with prior clinical studies, the most notable events that appeared to be associated with MBV were mild-moderate taste disturbance, nausea, and diarrhea. In conclusion, maribavir prophylaxis reduced the rate of CMV infection compared to placebo, with a favorable safety profile in this complex patient population. Phase 3 studies of maribavir in stem cell and solid organ transplant recipients are being planned.PlaceboMBV 100 mg BIDMBV 400 mg QDMBV 400 mg BIDN evaluable28272726CMV infection or disease based on:pp65 antigenemia11 (39%)4 (15%)5 (19%)4 (15%)p=0.046p=0.116p=0.053plasma CMV DNA PCR13 (46%)2 (7%)3 (11%)5 (19%)p=0.001p=0.007p=0.038Use of preemptive anti-CMV Rx16 (57%)4 (15%)8 (30%)4 (15%)p=0.001p=0.051p=0.002CMV disease only3 (11%)000p=0.089p=0.084p=0.091p values represent comparison to placebo (stratified by myeloablative or nonmyeloablative SCT)

Whole blood real-time quantitative PCR for cytomegalovirus infection follow-up in transplant recipients

Background Cytomegalovirus (CMV) remains a major opportunistic agent among transplant recipients. While detection of CMV pp65-lower matrix protein (pp65Ag) is still widely used for monitoring CMV infection, real-time PCR assays have been recently developed for routine quantitation of CMV DNA. However, correlations are lacking between results of pp65Ag and quantitative PCR assays and there is no consensus yet as to the more appropriate blood compartment (whole blood (WB), leukocytes, plasma) to be tested with PCR assays. Objectives The aims of the study were to determine, in a population of transplant recipients: (i) the correlation between pp65Ag and CMV quantitative real-time PCR in our setting and (ii) the utility of plasma CMV DNA quantitation in comparison to WB quantitation. Methods In 170 blood samples (from 61 solid organ or bone marrow transplant recipients) with pp65Ag results, CMV quantitation was performed in WB and plasma using an in-house real-time quantitative PCR. Results Real-time PCR and pp65Ag results in WB were correlated: thresholds of 10 and 50(+) cells/200,000 cells were equivalent to 3.3 log 10 copies/mL (2000 copies/mL) and 3.8 log 10 copies/mL (6300 copies/mL), respectively. When WB viral load was ≥3.6 log 10 copies/mL, the risk to have a negative plasma CMV DNA result was ≤2.5%. Conclusions For the routine exploration of a single compartment, whole blood would represent a suitable compromise: easy processing for a sensitive assay. The 3.6 log 10 copies/mL threshold, which could help in identifying active CMV infection, deserves further evaluation.