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

Whole Blood versus Plasma Samples-How Does the Type of Specimen Collected for Testing Affect the Monitoring of Cytomegalovirus Viremia?

Viral infections, or their reactivations, are one of the most important groups of transplantation complications that can occur among recipients of both hematopoietic cells and solid organ transplants. They are the most commonly caused by cytomegalovirus (CMV). Currently, the use of whole blood or plasma samples is recommended for CMV viral load monitoring. The aim of the study was to assess and compare the level of CMV DNA, depending on the type of clinical material—whole blood or plasma fraction derived from the same patient. The studies were carried out on 156 whole blood samples in which the presence of CMV genetic material was confirmed and the corresponding plasma samples from the same rounds of sampling. CMV DNA was not present in 59 (37.8%) of plasma samples compared to whole blood-positive counterparts. Of the samples positive in both types of clinical specimen, 77 (79.4%) had higher viral DNA levels in the whole blood samples. There were statistically significant differences in the detected CMV DNA load in the whole blood compared to plasma fraction counterparts (p < 0.001). The detected CMV DNA value is usually higher in whole blood compared to plasma samples of the same patient. Due to the variability in CMV viral load depending on the clinical material used for a particular patient, one type of specimen should be always used consequently for CMV viremia monitoring.

Prognosis of Human Cytomegalovirus in Cancer Patients Undergoing Chemotherapeutic Treatment in Egypt and an Emergent Prevalence of Glycoprotein B-5

The human cytomegalovirus (HCMV) is a global opportunistic β-herpes virus causing severe diseases in immune-compromised patients, such as malignant tumor patients, especially those undergoing chemotherapeutic treatment. This study aimed to determine the prevalence of HCMV-DNA in chemotherapeutic treatment naive cancer patients, and after chemotherapy, to compare between conventional nested PCR and ELISA techniques for the detection of HCMV, and to detect glycoprotein B genotypes. Plasma and serum samples before and after three chemotherapy cycles were collected from 49 chemotherapy-naive cancer patients. DNA was extracted from plasma samples using QIAamp® DNA Mini kit. HCMV-DNA was detected using a nested PCR technique. Multiplex nested PCR was used for HCMV-glycoprotein B (gB) genotyping. HCMV-IgG and -IgM were detected using ELISA technique. Thirty one (63.3 %) of the 49 plasma samples of the chemotherapy-naïve cancer patients were positive for HCMV-DNA; 21 of which remained positive after chemotherapy. However, 18 samples were negative of which 16 became positive after chemotherapy. gB-5 was the most common glycoprotein genotype detected (80.6 %), followed by gB-1, gB-3, gB-4, and gB-2. HCMV IgG was detected in the 49 serum samples of chemotherapy-naïve patients, and after exposure to chemotherapy. HCMV-DNA is commonly identified in cancer patients. Its detection after chemotherapy exposure may suggest HCMV reactivation. The most common genotype detected in cancer patients in Egypt is gB-5 in contrast to earlier research. IgG was detected in all patients. This indicates that HCMV is endemic in Egypt, necessitating the development of public awareness campaigns about HCMV infection and preventive strategies.

The Third International Consensus Guidelines on the Management of Cytomegalovirus in Solid-organ Transplantation

Despite recent advances, cytomegalovirus (CMV) infections remain one of the most common complications affecting solid organ transplant recipients, conveying higher risks of complications, graft loss, morbidity, and mortality. Research in the field and development of prior consensus guidelines supported by The Transplantation Society has allowed a more standardized approach to CMV management. An international multidisciplinary panel of experts was convened to expand and revise evidence and expert opinion-based consensus guidelines on CMV management including prevention, treatment, diagnostics, immunology, drug resistance, and pediatric issues. Highlights include advances in molecular and immunologic diagnostics, improved understanding of diagnostic thresholds, optimized methods of prevention, advances in the use of novel antiviral therapies and certain immunosuppressive agents, and more savvy approaches to treatment resistant/refractory disease. The following report summarizes the updated recommendations.

Clinical evaluation of Roche COBAS® AmpliPrep/COBAS® TaqMan® CMV test using nonplasma samples

Cytomegalovirus (CMV) infection is a leading cause of loss of hearing, vision, and mental retardation in congenitally infected children. It is also associated with complications of organ transplant and opportunistic HIV coinfection. The Roche COBAS^® AmpliPrep/COBAS^® TaqMan^® CMV test is an FDA-approved test that measures CMV DNA viral load in plasma for the diagnosis and management of patients at risk of CMV-associated diseases. Besides plasma, CMV is often found in bronchoalveolar lavage (BAL), cerebrospinal fluid (CSF), and urine. Thus, monitoring of CMV for critical care of patients in these nonplasma samples becomes necessary. The objective of this study was to conduct an analytic and clinical feasibility study of the Roche CMV test in BAL, CSF, and urine. The lower limit of detection, analytic measurement range, assay sensitivity, specificity, and precision were determined. Results of this study showed that the lower limit of detections were 50, 100, and 300 IU/mL for BAL, CSF, or urine, respectively. The analytic measurement ranges were from log₁₀ 2.48 to log₁₀ 5.48. The assay specificity was 94.4% for BAL and 100% for CSF and urine. The assay precision was all within the acceptable range. The performance of Roche test was further compared with 2 comparators including the RealTime CMV assay (Abbott Molecular) and a CMV Quantitative Polymerase Chain Reaction test (Vela Diagnostics). There was a general positive correlation between the Roche method and the Abbott or the Vela method. Overall, this study suggests that the Roche CMV test is suitable for the quantification of CMV viral load DNA in the described nonplasma samples.

Comparison of Two Commercial Automated Nucleic Acid Extraction and Integrated Quantitation Real-Time PCR Platforms for the Detection of Cytomegalovirus in Plasma

Quantitation of cytomegalovirus (CMV) viral load in the transplant patients has become a standard practice for monitoring the response to antiviral therapy. The cut-off values of CMV viral load assays for preemptive therapy are different due to the various assay designs employed. To establish a sensitive and reliable diagnostic assay for preemptive therapy of CMV infection, two commercial automated platforms including m2000sp extraction system integrated the Abbott RealTime (m2000rt) and the Roche COBAS AmpliPrep for extraction integrated COBAS Taqman (CAP/CTM) were evaluated using WHO international CMV standards and 110 plasma specimens from transplant patients. The performance characteristics, correlation, and workflow of the two platforms were investigated. The Abbott RealTime assay correlated well with the Roche CAP/CTM assay (R² = 0.9379, P<0.01). The Abbott RealTime assay exhibited higher sensitivity for the detection of CMV viral load, and viral load values measured with Abbott RealTime assay were on average 0.76 log₁₀ IU/mL higher than those measured with the Roche CAP/CTM assay (P<0.0001). Workflow analysis on a small batch size at one time, using the Roche CAP/CTM platform had a shorter hands-on time than the Abbott RealTime platform. In conclusion, these two assays can provide reliable data for different purpose in a clinical virology laboratory setting.

Systematic Evaluation of Different Nucleic Acid Amplification Assays for Cytomegalovirus Detection: Feasibility of Blood Donor Screening

Acute primary cytomegalovirus (CMV) infections, which commonly occur asymptomatically among blood donors, represent a significant risk for serious morbidity in immunocompromised patients (a major group of transfusion recipients). We implemented a routine CMV pool screening procedure for plasma for the identification of CMV DNA-positive donors, and we evaluated the sensitivities and performance of different CMV DNA amplification systems. Minipools (MPs) of samples from 18,405 individual donors (54,451 donations) were screened for CMV DNA using the RealStar CMV PCR assay (Altona Diagnostic Technologies), with a minimum detection limit of 11.14 IU/ml. DNA was extracted with a high-volume protocol (4.8 ml, Chemagic Viral 5K kit; PerkinElmer) for blood donor pool screening (MP-nucleic acid testing [NAT]) and with the Nuclisens easyMAG system (0.5 ml; bioMérieux) for individual donation (ID)-NAT. In total, six CMV DNA-positive donors (0.03%) were identified by routine CMV screening, with DNA concentrations ranging from 4.35 × 10(2) to 4.30 × 10(3) IU/ml. Five donors already showed seroconversion and detectable IgA, IgM, and/or IgG antibody titers (IgA(+)/IgM(+)/IgG(-) or IgA(+)/IgM(+)/IgG(+)), and one donor showed no CMV-specific antibodies. Comparison of three commercial assays, i.e., the RealStar CMV PCR kit, the Sentosa SA CMV quantitative PCR kit (Vela Diagnostics), and the CMV R-gene PCR kit (bioMérieux), for MP-NAT and ID-NAT showed comparably good analytical sensitivities, ranging from 10.23 to 11.14 IU/ml (MP-NAT) or from 37.66 to 57.94 IU/ml (ID-NAT). The clinical relevance of transfusion-associated CMV infections requires further investigation, and the evaluated methods present powerful basic tools providing sensitive possibilities for viral testing. The application of CMV MP-NAT facilitated the identification of one donor with a window-phase donation during acute primary CMV infection.

Monitoring of cytomegalovirus viral loads by two molecular assays in whole-blood and plasma samples from hematopoietic stem cell transplant recipients

Cytomegalovirus (CMV) viral loads in hematopoietic stem cell transplant (HSCT) recipients are typically monitored using quantitative molecular assays. The Roche Cobas AmpliPrep/Cobas TaqMan CMV test (Cobas CMV) has recently been cleared by the FDA for the monitoring of CMV viral loads in plasma samples from transplant patients. In this study, we compare and correlate the viral loads obtained by a laboratory-developed test (LC CMV) (using Roche analyte-specific reagents [ASR] on the LightCycler 2.0) on whole-blood specimens with those obtained on corresponding plasma and whole-blood specimens by the Cobas CMV assay. Testing was performed on 773 archived patient specimens. The strength of the agreement was good for the two assays performed on whole blood (κ=0.6; 95% confidence interval [CI], 0.51 to 0.7) and moderate when the tests were performed on different sample types (κ=0.54; 95% CI, 0.47 to 0.62 for the LC CMV whole blood [WB] assay versus Cobas plasma [PL], and κ=0.57; 95% CI, 0.5 to 0.65 for the Cobas WB assay versus Cobas PL), although the difference was not statistically significant. Using a combination gold standard (i.e., a true positive was a specimen that was positive by two or more methods), the sensitivity and specificity of the assays were 78.8% and 99.3% for the LC CMV assay, 85.2% and 98.1% for the Cobas CMV WB assay, and 100% and 90.5% for Cobas CMV PL assay, respectively. A comparison of the CMV viral load trends in both plasma and whole blood from a few patients with multiple positive successive samples showed similar slopes, with differences in the slope ranging from 0.01 to 0.22. However, the absolute value for individual viral load differed markedly with whole-blood viral loads, being on average 0.5- to 1.22-log higher than those in plasma. The Cobas CMV assay provides a valid option for the monitoring of viral loads in transplant patients. Due to its increased sensitivity, the detection of CMV DNA in patients with low viral loads (i.e., those below limit of quantification [LOQ]) is increased with the Cobas CMV assay in plasma specimens. Longitudinal prospective studies will be needed to examine the clinical significance of these low-level viral loads.

Clinical characteristics and therapy exploration of active human cytomegalovirus infection in 105 lupus patients

Systemic lupus erythematosus (SLE) has protean clinical manifestations of varying severity over the course of its onset, exacerbation, remission and flare that could often pose significant challenges for clinicians in their decision making as to whether to treat aggressively or to look for concurrent conditions such as infection with opportunistic pathogens. Human cytomegalovirus (HCMV) is one of those pathogens and is frequently encountered in our daily management of lupus patients. To investigate the clinical characteristics and therapeutic options of active HCMV infection in patients with SLE, we retrospectively reviewed clinical data of 105 inpatients in our department of Rheumatology and Clinical Immunology of Peking Union Medical College Hospital (PUMCH) diagnosed with both SLE and active HCMV infection from January 2006 to January 2012. Three groups were designated that included 42 cases of HCMV triggering SLE, 31 cases of HCMV exacerbating SLE, and 32 cases of HCMV mimicking SLE flare based on the relationship of HCMV infection and SLE. 1) Hematocytopenia (81%), fever (73.3%) and liver dysfunction (54.3%) were the most common clinical manifestations. The differences among the three groups with regard to butterfly erythema, cutaneous vasculitis, arthritis, serositis, central nervous system involvement and renal involvement were statistically significant (p < 0.05). 2) Positive rate of HCMV-pp65, compared with HCMV-IgM and HCMV-DNA, was the highest (84.9%) in patients with SLE and active HCMV infection. 3) Following 14-21 days of inductive treatment with ganciclovir, a total of 26 out of 56 patients were still positive with HCMV-IgM (nine of 19, 47.6%) and pp65 (17/37, 45.9%). Among them, seven cases suffered HCMV relapses in three months with six cases of sustained HCMV-pp65 antigenemia. In conclusion, hematocytopenia, fever and liver dysfunction should remind us to consider HCMV infection. Butterfly erythema, cutaneous vasculitis, arthritis, serositis, central nervous system involvement and renal lesion were relatively characteristic symptoms of lupus activity. HCMV-pp65 is a sensitive indicator to guide antiviral therapy. Induction therapy using ganciclovir with a duration of 14∼21 days is not sufficient, and continued HCMV-pp65 positivity may require prolonged antiviral treatment in lupus patients.

Peripheral blood leukocytes and serum nested polymerase chain reaction are complementary methods for monitoring active cytomegalovirus infection in transplant patients

BACKGROUND

Human cytomegalovirus is an important cause of morbidity and mortality in immunocompromised patients. Qualitative polymerase chain reaction (PCR) has proven to be a sensitive and effective technique in defining active cytomegalovirus infection, in addition to having low cost and being a useful test for situations in which there is no need for quantification. Real-time PCR has the advantage of quantification; however, the high cost of this methodology makes it impractical for routine use.

OBJECTIVE

To apply a nested PCR assay to serum (sPCR) and to evaluate its efficiency to diagnose active cytomegalovirus infection compared with PCR of peripheral blood leukocytes (L-PCR).

METHODS

Samples of 37 patients were prospectively evaluated. An internal control was created and applied to sPCR to exclude false-negative results.

RESULTS

In total, 21 patients (57%) developed active cytomegalovirus infection. After analyzing the two methods for the diagnosis of active infection, higher sensitivity and negative predictive value of the L-PCR versus sPCR (100% versus 62%), and higher specificity and positive predictive value of sPCR versus L-PCR (81% versus 50% and 72%, respectively) were observed. Discordant results were observed in 11 patients who were L-PCR-positive but sPCR-negative for active cytomegalovirus infection, five of whom developed clinical symptoms of cytomegalovirus. Clinical symptoms were observed in 14 patients, 12 of whom were diagnosed with active infection by nested L-PCR (P=0.007) and seven by nested sPCR (P=0.02). Higher specificity and a positive predictive value for sPCR were observed.

CONCLUSION

Nested L-PCR and sPCR were considered to be complementary methods for the diagnosis and management of symptomatic cytomegalovirus infection.

Updated international consensus guidelines on the management of cytomegalovirus in solid-organ transplantation

Cytomegalovirus (CMV) continues to be one of the most common infections after solid-organ transplantation, resulting in significant morbidity, graft loss, and adverse outcomes. Management of CMV varies considerably among transplant centers but has been become more standardized by publication of consensus guidelines by the Infectious Diseases Section of The Transplantation Society. An international panel of experts was reconvened in October 2012 to revise and expand evidence and expert opinion-based consensus guidelines on CMV management, including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues. The following report summarizes the recommendations.

CMV: Prevention, Diagnosis and Therapy

Cytomegalovirus (CMV) is the most common infection after organ transplantation and has a major impact on morbidity, mortality and graft survival. Optimal prevention, diagnosis and treatment of active CMV infection enhance transplant outcomes, and are the focus of this section. Methods to prevent CMV include universal prophylaxis and preemptive therapy; each has its merits, and will be compared and contrasted. Diagnostics have improved substantially in recent years, both in type and quality, allowing for more accurate and savvy treatment; advances in diagnostics include the development of an international standard, which should allow comparison of results across different methodologies, and assays for cellular immune function against CMV. Therapy primarily involves ganciclovir, now rendered more versatile by data suggesting oral therapy with valganciclovir is not inferior to intravenous therapy with ganciclovir. Treatment of resistant virus remains problematic, but is enhanced by the availability of multiple novel therapeutic agents.

Molecular detection of herpesviruses

In routine molecular diagnostics, detection of herpesviruses has made a major impact. Infection with herpesviruses is indicated by demonstrating the presence of the virus in selected specimens. Rapid and reliable detection of herpesvirus DNA helps to decrease the lethality as well as the sequelae of herpesvirus infection in patients at risk. This chapter discusses specimen types and both laboratory-developed and commercially available assays useful for molecular detection of herpesviruses. To meet the need for reliable laboratory results, it is advisable to employ maximum automated and standardized kits based on reagents and standards of reproducible high quality. In the routine diagnostic laboratory, introduction of IVD/CE and/or FDA-labeled tests is preferred.

International consensus guidelines on the management of cytomegalovirus in solid organ transplantation

Cytomegalovirus (CMV) remains one of the most common infections after solid organ transplantation, resulting in significant morbidity, graft loss, and occasional mortality. Management of CMV varies considerably among transplant centers. A panel of experts on CMV and solid organ transplant was convened by The Infectious Diseases Section of The Transplantation Society to develop evidence and expert opinion-based consensus guidelines on CMV management including diagnostics, immunology, prevention, treatment, drug resistance, and pediatric issues.

Monitoring human cytomegalovirus infection with nested PCR: comparison of positive rates in plasma and leukocytes and with quantitative PCR

BACKGROUND

Human cytomegalovirus (HCMV) infection poses a significant health threat to immunocompromised individuals. Here we performed this study to set up a highly sensitive nested PCR method applicable for detecting HCMV infection in high-risk individuals. In this work, 106 blood specimens from 66 patients with potential HCMV infection were obtained. Total DNA was extracted separately from plasma and peripheral blood leukocytes (PBL) of each sample. HCMV DNA was detected in parallel by nested PCR and quantitative real-time PCR (qRT-PCR), and the results were compared.

RESULTS

Serial dilution test revealed that the detection limit of nested PCR was 180 copies/ml. The nested PCR showed a higher positive rate than qRT-PCR (34.9% vs. 12.3%, p < 0.001). The positive rate of nested PCR based on PBL DNA was significantly higher than that based on plasma DNA (34.9% vs. 18.9%, p = 0.002). Of the 14 patients with serial samples, 11 were positive for HCMV DNA in PBL while only 7 were positive in plasma. Moreover, for each patient, nested PCR using PBL DNA also detected more positive samples than that using plasma DNA.

CONCLUSION

Combined use of nested PCR with PBL DNA is highly sensitive in defining HCMV infection. This assay is particularly useful in the case of quantification not essential.

Comparison of QIAGEN automated nucleic acid extraction methods for CMV quantitative PCR testing

We examined the effect of nucleic acid extraction methods on the analytic characteristics of a quantitative polymerase chain reaction (PCR) assay for cytomegalovirus (CMV). Human serum samples were extracted with 2 automated instruments (BioRobot EZ1 and QIAsymphony SP, QIAGEN, Valencia, CA) and CMV PCR results compared with those of pp65 antigenemia testing. Both extraction methods yielded results that were comparably linear and precise, whereas the QIAsymphony SP had a slightly lower limit of detection (1.92 log(10) copies/mL vs 2.26 log(10) copies/mL). In both cases, PCR was more sensitive than CMV antigen detection, detecting CMV viremia in 12% (EZ1) and 21% (QIAsymphony) of antigen-negative specimens. This study demonstrates the feasibility of using 2 different extraction techniques to yield results within 0.5 log(10) copies/mL of the mean value, a level that would allow for clinical comparison between different laboratory assays.

Current applications and future trends of molecular diagnostics in clinical bacteriology

Molecular diagnostics of infectious diseases, in particular, nucleic-acid-based methods, are the fastest growing field in clinical laboratory diagnostics. These applications are stepwise replacing or complementing culture-based, biochemical, and immunological assays in microbiology laboratories. The first-generation nucleic acid assays were monoparametric such as conventional tests, determining only a single parameter. Improvements and new approaches in technology now open the possibility for the development of multiparameter assays using microarrays, multiplex nucleic acid amplification techniques, or mass spectrometry, while the introduction of closed-tube systems has resulted in rapid microbial diagnostics with a subsequently reduced contamination risk. Whereas the first assays were focused on the detection and identification of microbial pathogens, these new technologies paved the way for the parallel determination of multiple antibiotic resistance determinants or to perform microbial epidemiology and surveillance on a genetic level.