Prediction of cytomegalovirus (CMV) plasma load from evaluation of CMV whole-blood load in samples from renal transplant recipients

Primary, Secondary, and Tertiary Prevention of Congenital Cytomegalovirus Infection

Cytomegalovirus infection is the most common congenital infection, affecting about 1% of births worldwide. Several primary, secondary, and tertiary prevention strategies are already available during the prenatal period to help mitigate the immediate and long-term consequences of this infection. In this review, we aim to present and assess the efficacy of these strategies, including educating pregnant women and women of childbearing age on their knowledge of hygiene measures, development of vaccines, screening for cytomegalovirus infection during pregnancy (systematic versus targeted), prenatal diagnosis and prognostic assessments, and preventive and curative treatments in utero.

Cytomegalovirus DNAemia Requiring (Val)Ganciclovir Treatment for More Than 8 Weeks Is a Key Factor in the Development of Antiviral Drug Resistance

Background

Prolonged (val)ganciclovir [(V)GCV] exposure for ≥6 weeks is a known predisposing factor for cytomegalovirus (CMV) drug resistance. However, the selection of this threshold was based on limited data. In this study, we sought to reappraise the risk factors for the development of (V)GCV resistance through a specific focus on kidney transplant recipients (KTRs).

Methods

This single-center retrospective study included 313 consecutive KTRs treated for a first CMV episode. Adjusted Cox multivariate regression analysis was used for identifying independent risk factors.

Results

Antiviral drug resistance was identified in 20 (6%) KTRs. A cumulative (V)GCV exposure for more than 6 weeks (regardless of the viral load) was not associated with antiviral drug resistance (hazard ratio [HR] = 2.45, 95% confidence interval [CI] = 0.33-18.30, P = .38). In contrast, persistent CMV DNAemia requiring (V)GCV treatment for more than 8 weeks was the main independent risk factor for antiviral drug resistance (HR = 11.68, 95% CI = 2.62-52.01, P = .001). The (V)GCV treatment for more than 8 weeks was given to 9% and 18% of patients who had persistent or recurrent CMV DNAemia, respectively. These scenarios were associated with the occurrence of drug resistance in 39% and 12% of cases, respectively.

Conclusions

Cumulative (V)GCV exposure ≥6 weeks regardless of the viral load is not associated with antiviral drug resistance. In contrast, prolonged exposure to (V)GCV during CMV replication (with a cutoff ³8 weeks) seems to be a key factor.

Distinctive phenotype for HLA-E- versus HLA-A2-restricted memory CD8 αβT cells in the course of HCMV infection discloses features shared with NKG2C+CD57+NK and δ2-γδT cell subsets

The human cytomegalovirus (HCMV) triggers both innate and adaptive immune responses, including protective CD8⁺ αβT cells (CD8T) that contributes to the control of the infection. In addition to CD8T restricted by classical HLA class Ia molecules, HCMV also triggers CD8T recognizing peptides from the HCMV UL40 leader peptide and restricted by HLA-E molecules (HLA-E_UL40 CD8T). This study investigated the frequency, phenotype and functions of HLA-E_UL40 CD8T in comparison to the immunodominant HLA-A2_pp65 CD8T upon acute (primary or secondary infection) or chronic infection in kidney transplant recipients (KTR) and in seropositive (HCMV⁺) healthy volunteer (HV) hosts. The frequency of hosts with detected HLA-E_UL40 CD8T was similar after a primary infection (24%) and during viral latency in HCMV+ HV (26%) and equal to the frequency of HLA-A2_pp65 CD8T cells in both conditions (29%). Both CD8T subsets vary from 0.1% to >30% of total circulating CD8T according to the host. Both HLA-E_UL40 and HLA-A2_pp65 CD8T display a phenotype specific of CD8⁺ TEMRA (CD45RA⁺/CCR7^-) but HLA-E_UL40 CD8T express distinctive level for CD3, CD8 and CD45RA. Tim3, Lag-3, 4-1BB, and to a lesser extend 2B4 are hallmarks for T cell priming post-primary infection while KLRG1 and Tigit are markers for restimulated and long lived HCMV-specific CD8T responses. These cell markers are equally expressed on HLA-E_UL40 and HLA-A2_pp65 CD8T. In contrast, CD56 and PD-1 are cell markers discriminating memory HLA-E- from HLA-A2-restricted CD8T. Long lived HLA-E_UL40 display higher proliferation rate compared to HLA-A2_pp65 CD8T consistent with elevated CD57 expression. Finally, a comparative immunoprofiling indicated that HLA-E_UL40 CD8T, divergent from HLA-A2_pp65 CD8T, share the expression of CD56, CD57, NKG2C, CD158 and the lack of PD-1 with NKG2C⁺CD57+ NK and δ2^-γδT cells induced in response to HCMV and thus defines a common immunopattern for these subsets.

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.

Cytomegalovirus Specific Serological and Molecular Markers in a Series of Pregnant Women With Cytomegalovirus Non Primary Infection

(1) Background: In a period where systematic screening of CMV during pregnancy is still debated, diagnosis of non primary infection (NPI) remains challenging and an obstacle to systematic screening. Our aim is to report kinetics of serological and molecular CMV markers of NPI. (2) Methods: We identified immunocompetent pregnant women with CMV NPI as women known to be seropositive for CMV before pregnancy who gave birth to cCMV infected infants. We performed CMV-IgG, CMV-IgM, CMV-IgG avidity and CMV PCR retrospectively on sequential serum samples collected during pregnancy. (3) Results: We collected 195 serum samples from 53 pregnant women with NPI during pregnancy. For 29/53 (55%) patients, no markers of active infection were observed (stable IgG titers, negative IgM and negative PCR). CMV PCR was positive in at least one serum for 18/53 (34%) patients and median viral load was 46 copies/mL, IQR (21-65). (4) Conclusions: For more than half of patients with confirmed CMV NPI during pregnancy, available diagnostic tools are liable to fail in detecting an active infection. These should therefore not be used and universal neonatal screening for CMV remains the only way to detect all cCMV infections.

Contribution of Serum Cytomegalovirus PCR to Diagnosis of Early CMV Primary Infection in Pregnant Women

(1) Background: What is the role of serum CMV PCR in the diagnosis of recent primary infection (PI) in pregnant women when IgG avidity is uninformative? (2) Methods: Retrospective cohort study to compare serum versus whole blood CMV PCR. (a) Qualitative assessment: CMV PCR was performed on 123 serum samples and 74 whole blood samples collected from 132 pregnant women with recent CMV PI. PCR positivity rate was used to calculate sensitivity in serum and whole blood. (b) Quantitative assessment: CMV PCR was performed on 72 paired samples of serum and whole blood collected on the same day from 57 patients. (3) Results: In pregnant women, PCR positivity rate was 89% for serum samples versus 100% in whole blood in the case of very recent PI (<15 days), but only 27% in serum versus 68% in whole blood for PI occurring from 6 weeks to 3 months before. Comparing CMV viral loads between serum and whole blood, we determined the limit of CMV DNA detection in serum as 3 log copies/mL (whole blood equivalent). (4) Conclusions: Serum CMV PCR is reliable in confirming PI in cases when only IgM is detected. It is therefore a valuable tool in introducing valaciclovir treatment as early as possible to prevent mother-to-child CMV transmission.

Comparison of early and late Pneumocystis jirovecii Pneumonia in kidney transplant patients: the Korean Organ Transplantation Registry (KOTRY) Study

Late Pneumocystis jirovecii pneumonia (PJP) is not rare in the era of universal prophylaxis after kidney transplantation. We aimed to determine the nationwide status of PJP prophylaxis in Korea and compare the incidence, risk factors, and outcomes of early and late PJP using data from the Korean Organ Transplantation Registry (KOTRY), a nationwide Korean transplant cohort. We conducted a retrospective analysis using data of 4,839 kidney transplant patients from KOTRY between 2014 and 2018, excluding patients who received multi-organ transplantation or were under 18 years old. Cox regression analysis was performed to determine risk factors for early and late PJP. A total of 50 patients developed PJP. The number of patients who developed PJP was same between onset before 6 months and onsets after 6 months. There were no differences in the rate, duration, or dose of PJP prophylaxis between early and late PJP. Desensitization, higher tacrolimus dose at discharge, and acute rejection were associated with early PJP. In late PJP, old age as well as acute rejection were significant risk factors. In conclusion late PJP is as common and risky as early PJP and requires individualized risk-based prophylaxis, such as prolonged prophylaxis for old patients with a history of rejection.

Molecular Detection and Glycoprotein B (UL55) Genotyping of Cytomegalovirus among Sudanese Renal Transplant Recipients

Background

Cytomegalovirus (CMV) is the most common opportunistic pathogen among renal transplants with significant morbidity and mortality. This study was designed to detect CMV DNA and to determine the frequency of different glycoprotein B (UL55) genotypes among Sudanese renal transplant recipients.

Methods

One hundred and four renal transplant recipients were included in this study. A blood specimen was collected from each recipient. DNA was extracted from plasma using the QIAamp DNA mini kit. CMV amplification and quantification were performed using CMV Real-RT Quant kits. Genotyping of human CMV gB was carried out by nested PCR and sequencing of the highly diverse region of gB.

Results

CMV DNA was detected in 40/104 (38.5%) of renal transplant recipients. The average of the CMV DNA viral load was 358 × 10⁴ copies/ml (6.5 log₁₀) ranging from 62 copies/ml (1.8 log₁₀) to 1.43 × 10⁸ copies/ml (9 log₁₀). CMV viremia was detected in 60% of recipients of less than 1–12 months, 17% of 13–24, 10% of 25–36, 5% of 37–48, and 8% in more than 48 months posttransplantation with no association (p = 0.296) between CMV viremia and postrenal transplantation time. The association between the type of immunosuppressive drugs and high viral loads (>1000 copies/ml) showed a significant difference (p = 0.05). The association between CMV loads of >1000 copies/ml and symptoms of CMV disease was highly significant (p ≤ 0.001). Fever 7 (41%), fever and leucopenia 6 (35%), and gastrointestinal disease 4 (24%) were the most common symptoms of CMV disease. CMV genotyping revealed 8 cases (80%) for gB3 and 2 cases (20%) for gB4 genotypes. The most frequent genotype among Sudanese renal transplant recipients was gB3.

Conclusions

The frequency of CMV DNA is high among Sudanese renal transplant recipients. CMV gB3 is the most predominant glycoprotein B genotype in Sudanese renal transplant recipients.

mTOR Inhibitors Prevent CMV Infection through the Restoration of Functional αβ and γδ T cells in Kidney Transplantation

BACKGROUND

The reported association of mTOR-inhibitor (mTORi) treatment with a lower incidence of cytomegalovirus (CMV) infection in kidney transplant recipients (KTR) who are CMV seropositive (R+) remains unexplained.

METHODS

The incidence of CMV infection and T-cell profile was compared between KTRs treated with mTORis and mycophenolic acid (MPA), and in vitro mTORi effects on T-cell phenotype and functions were analyzed.

RESULTS

In KTRs who were R+ and treated with MPA, both αβ and γδ T cells displayed a more dysfunctional phenotype (PD-1+, CD85j+) at day 0 of transplantation in the 16 KTRs with severe CMV infection, as compared with the 17 KTRs without or with spontaneously resolving CMV infection. In patients treated with mTORis (n=27), the proportion of PD-1+ and CD85j+ αβ and γδ T cells decreased, when compared with patients treated with MPA (n=44), as did the frequency and severity of CMV infections. mTORi treatment also led to higher proportions of late-differentiated and cytotoxic γδ T cells and IFNγ-producing and cytotoxic αβ T cells. In vitro, mTORis increased proliferation, viability, and CMV-induced IFNγ production of T cells and decreased PD-1 and CD85j expression in T cells, which shifted the T cells to a more efficient EOMES^low Hobit^high profile. In γδ T cells, the mTORi effect was related to increased TCR signaling.

CONCLUSION

Severe CMV replication is associated with a dysfunctional T-cell profile and mTORis improve T-cell fitness along with better control of CMV. A dysfunctional T-cell phenotype could serve as a new biomarker to predict post-transplantation infection and to stratify patients who should benefit from mTORi treatment.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Proportion of CMV Seropositive Kidney Transplant Recipients Who Will Develop a CMV Infection When Treated With an Immunosuppressive Regimen Including Everolimus and Reduced Dose of Cyclosporine Versus an Immunosuppressive Regimen With Mycophenolic Acid and Standard Dose of Cyclosporine A (EVERCMV), NCT02328963.

Survey of HCMV in allogenic and autologous stem cell transplantation by real-time PCR in Kermanshah, west of Iran

INTRODUCTION

Human Cytomegalovirus (HCMV) is the most important viral pathogen in people undergoing bone marrow transplantation (BMT). HCMV detection in the early stages makes is possible to save the patients' lives through immediate and timely treatment. The aim of this study was to investigate the status of HCMV using the real-time PCR method in BMT patients in Kermanshah, west of Iran.

METHODS

HCMV monitoring was done in 120 patients who underwent BMT, 38 allogeneic cases and 82 autologous cases, using the ELISA serology test before transplantation. The participants were followed up 100 days after transplantation for HCMV detection in blood samples using real-time PCR. Preemptive therapy started with Ganciclovir and Foscarnet when the viral load was > 200 HCMV DNA copies/ml.

RESULTS

Despite preemptive therapy, infection recurred in less than 1 month. HCMV recurred more frequently in patients undergoing allogenic transplation versus those receiving autologous transplantation. Recurrence was seen in 5 patients receiving allogenic transplantation. HCMV recurrence occurred in five patients with allogeneic transplantation. Twelve patients undergoing allogeneic or autologous transplantation (83%) and a virus load of > 1000 copies/ml showed HCMV-related symptoms. Three patients died, two due to HCMV-related pneumonia and the other one due to a fungal infection.

CONCLUSION

Real-time PCR may be a useful method for quantification and monitoring of HCMV recurrence and may be helpful in choosing more efficient HCMV preemptive treatment in BMT recipients.

Identification of Predictive Markers and Outcomes of Late-onset Pneumocystis jirovecii Pneumonia in Kidney Transplant Recipients

Background

In the era of prophylaxis, Pneumocystis pneumonia (PCP) has become a late-onset opportunistic infection requiring indications for prolonged prophylaxis to be defined. The primary objective of our study was therefore to evaluate risk factors associated with late-onset PCP. The secondary objective was to assess the impact of this infection on graft and patient survival.

Methods

We conducted a French case-control study in Bordeaux and Toulouse center by matching 1 case to 1–2 controls from the same center based on the transplant date and the type of induction treatment.

Results

Seventy cases and 134 controls were included. PCP occurred at a median of 3 years after transplantation. The total lymphocyte count and CD4+ and CD8+ T-lymphocyte values were lower in the cases than in their matched controls on the day of infection and annually up to 4 years earlier. The covariables independently associated with PCP were the total lymphocyte count 1 year before Pneumocystis, mTOR inhibitors used as maintenance immunosuppressive drugs, and the administration of corticosteroid boluses used in acute rejection. A total lymphocyte count threshold &lt;1000/µL offered the best predictive value for infection occurrence. PCP was associated with high incidence of graft loss and patient death (30% and 17% respectively, 3 years after PCP).

Conclusions

Pneumocystis pneumonia has dramatic consequences in kidney transplant recipients; a targeted prophylaxis based on simple criteria, such as chronic lymphopenia and/or history of corticosteroid boluses, could be useful to avoid life-threatening complications.

Different impact of rATG induction on CMV infection risk in D+R- and R+ KTRs

BACKGROUND

Rabbit antithymocyte globulin (rATG) induction is associated with profound immunosuppression, leading to a higher risk of cytomegalovirus (CMV) infection compared with anti-interleukin 2 receptor antibody (anti-IL-2RA). However, this risk, depending on the baseline CMV serological recipient/donor status, is still controversial.

METHODS

The CMV DNAemia-free survival between rATG- and anti-IL-2RA-treated patients was analyzed in donor-positive/recipient-negative (D+R-) and recipient-positive (R+) patients in 1 discovery cohort of 559 kidney transplant recipients (KTRs) and 2 independent cohorts (351 and 135 kidney KTRs). The CMV-specific cell-mediated immunity (CMI) at baseline and at different time points after transplantation was assessed using an interferon γ enzyme-linked immunosorbent spot assay.

RESULTS

rATG increased the risk of CMV DNAemia in R+ but not in D+R- KTRs. In R+ CMI-positive (CMI+) patients, the CMV DNAemia rate was higher in rATG-treated than in anti-IL-2RA-treated patients; no difference was observed among R+ CMI-negative (CMI-) patients. Longitudinal follow-up demonstrated a deeper depletion of preformed CMV CMI in R+ rATG-treated patients.

CONCLUSIONS

D+R- KTRs have the highest risk of CMV DNAemia, but rATG adds no further risk. Among R+ KTRs, we described 3 groups, the least prone being R+CMI+ KTRs without rATG, then R+CMI+ KTRs with rATG, and finally R+CMI- KTRs. CMV serostatus, baseline CMV-specific CMI, and induction therapy may lead to personalized preventive therapy in further studies.

Effect of mTOR inhibitors during CMV disease in kidney transplant recipients: Results of a pilot retrospective study

mTOR inhibitors exert a preventive effect on cytomegalovirus (CMV) disease in CMV seropositive (R+) kidney transplant recipients, but their impact during the curative treatment of CMV disease in high-risk kidney transplant recipients has not been investigated. We aimed to evaluate the efficacy and tolerance of mTOR inhibitors compared with mycophenolic acid in 63 consecutive kidney transplant recipients (80% of D+R-) suffering from CMV disease with a persistent or a recurrent CMV DNAemia. In this monocentric retrospective study, 16 had their treatment converted to mTOR inhibitors and 47 did not. The Kaplan-Meier curves did not show any significant differences in CMV DNAemia eradication (77% vs. 88% respectively; hazard ratio (HR), 1.648 [95% confidence interval (CI), 0.913-2.973]; log-rank test, P = .132), DNAemia recurrence (36% vs. 47%; HR, 1.517 [95% CI, 0.574-4.007]; log-rank test, P = .448) and CMV clinical recurrence (17% vs. 27%; HR, 1.375 [95% CI, 0.340-5.552]; log-rank test, P = .677) between patients who received mTOR inhibitors and those who did not. These results were confirmed in uni- and multivariate time-dependent Cox regressions. In summary, conversion from mycophenolic acid to mTOR inhibitors seems inadequate for improving CMV clearance or in better preventing CMV recurrences during severe or persistent CMV disease.

An update on the treatment of cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation

Introduction: Human Cytomegalovirus (CMV) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Standard treatment options have for long been limited to a small number of effective drugs with significant toxicities.Areas covered: In this manuscript, the authors update a previous review summarizing recent developments in the virology lab and their possible implications for treatment strategies at bedside. In particular, the authors focused on new antiviral drugs already available and under investigation in clinical trials and innovative immunotherapeutic approaches, including adoptive T-cell therapy and vaccines.Expert opinion: Broader knowledge of CMV biology and its relationship with the host immune system is greatly contributing to the development of novel therapeutic approaches. The availability of new drugs, the improved techniques for virological testing and the more accurate patient risk stratification allow to better individualize treatment, limiting toxicity while sparing antiviral effects. The role of immunotherapy is clearly emerging and will further expand our treatment armamentarium.

Treatment and Prevention of CMV Disease in Transplant Recipients: Current Knowledge and Future Perspectives

This review summarizes the significant impact of cytomegalovirus (CMV) infection on solid organ and hematopoietic stem cell transplant recipients. A discussion of the various CMV prevention and treatment strategies is provided, including a detailed description of each of the available CMV antiviral drugs.

Active and Persistent Cytomegalovirus Infections Affect T Cells in Young Adult HIV Patients Commencing Antiretroviral Therapy

Altered T cell profiles have been linked with metrics of persistent cytomegalovirus (CMV) infections in healthy aging and older HIV patients stable on antiretroviral therapy (ART). In this study, we use CMV DNA to identify active infections, and levels of CMV-reactive antibody to assess the persistent burden of CMV in a longitudinal study of 78 young adult patients beginning ART in Jakarta, Indonesia, with <200 CD4 T cells/μL. CMV antibodies, inflammatory markers (C-reactive protein [CRP], soluble interferon-α/β receptor) and T cell phenotypes were assessed before ART (V0) and after 1, 3, 6, and 12 months (V1-V12). CMV DNA was detected in 41 patients (52%) at V0, irrespective of CD4 T cell counts, gender, age, or plasma HIV RNA. CMV DNA+ patients had higher levels of antibody reactive with CMV Immediate Early 1 (IE-1) at V0 and V12 (p = 0.04), and with CMV lysate at V12 (p = 0.01). Detectable CMV DNA did not align with inflammatory markers, but associated with lower CD4/CD8 ratios until V3. CMV antibody levels correlated inversely with proportions of naive CD4 and CD8 T cells, and directly with proportions of CD57⁺ and activated memory T cells (CD3⁺ CD45RA^-) after 3-12 months on ART. Overall, active CMV replication is common in HIV patients beginning ART in Indonesia and associates with low CD4/CD8 ratios. Elevated levels of CMV-reactive antibody measured on ART also mark a depletion of naive T cells, accumulation of memory T cells, and may be a stable metric of the burden of CMV.

Cytomegalovirus

Cytomegalovirus (CMV), the largest of the herpesviruses, causes a wide range of clinical syndromes, from asymptomatic infection to severe disease in immunocompromised hosts. Laboratory methods for diagnosis include molecular testing, antigenemia, culture, serology, and histopathology. Treatment of CMV infection and disease is indicated in selected immunocompromised hosts, and preventive approaches are indicated in high-risk groups. This chapter reviews the epidemiology, clinical aspects, and the laboratory diagnosis and management of CMV in immunocompromised hosts.

Easier Control of Late-Onset Cytomegalovirus Disease Following Universal Prophylaxis Through an Early Antiviral Immune Response in Donor-Positive, Recipient-Negative Kidney Transplants

Universal prophylaxis for cytomegalovirus (CMV) prevention is viable but, compared with a preemptive strategy, leads to higher incidence of late-onset disease (LOD) associated with poor patient and graft survival. The purpose of this study was to compare LOD with early onset disease (EOD), with a focus on the highest risk kidney transplant recipients (KTRs): CMV seronegative recipients transplanted from seropositive donors (D+R-). Since CMV control depends on both antiviral treatment and specific immune response, we also compared Vδ2-negative (Vδ2(neg) ) γδ T cell expansion involved in CMV infection resolution. EOD was defined as occurring <3 mo and LOD as occurring >3 mo after transplantation. Depending on the period, universal prophylaxis or preemptive treatment was used. Overall, 168 D+R- KTRs were included between 2003 and 2011. LOD was associated with a lower peak DNAemia (p = 0.04), fewer recurrences (odds ratio 0.16; 95% confidence interval 0.05-0.55; p = 0.01) and shorter anti-CMV curative treatment (40 vs. 60 days, p < 0.0001). As a corollary, we found that Vδ2(neg) γδ T cell expansion was faster in LOD than in EOD (31 vs. 168 days after the beginning of CMV disease, p < 0.0001). In D+R- KTRs, universal prophylaxis is associated with more LOD, which had better infection management and a faster immune response. These results support the use of universal prophylaxis over a preemptive strategy and reappraise outcomes of LOD.

Development and optimization of a sensitive TaqMan® real-time PCR with synthetic homologous extrinsic control for quantitation of Human cytomegalovirus viral load

Human cytomegalovirus (Human herpesvirus 5, HCMV) causes frequent asymptomatic infections in the general population. However, in immunosuppressed patients or congenitally infected infants, HCMV is related to high morbidity and mortality. In such cases, a rapid viral detection is crucial for monitoring the clinical outcome and the antiviral treatment. In this study, we optimized a sensitive biplex TaqMan® real-time PCR for the simultaneous detection and differentiation of a partial HCMV UL97 sequence and homologous extrinsic control (HEC) in the same tube. HEC was represented by a plasmid containing a modified HCMV sequence retaining the original primer binding sites, while the probe sequence was substituted by a phylogenetically divergent one (chloroplast CF0 subunit plant gene). It was estimated that the optimal HEC concentration, which did not influence the HCMV amplification is 1,000 copies/reaction. The optimized TaqMan® PCR demonstrated high analytical sensitivity (6.97 copies/reaction, CI = 95%) and specificity (100%). Moreover, the reaction showed adequate precision (repeatability, CV = 0.03; reproducibility, CV = 0.0027) and robustness (no carry-over or cross-contamination). The diagnostic sensitivity (100%) and specificity (97.8%) were adequate for the clinical application of the molecular platform. The optimized TaqMan® real-time PCR is suitable for HCMV detection and quantitation in predisposed patients and monitoring of the applied antiviral therapy. J. Med. Virol. 88:1604-1612, 2016. © 2016 Wiley Periodicals, Inc.

Which CMV viral load threshold should be defined as CMV infection in kidney transplant patients?

BACKGROUND

Cytomegalovirus infection (CMV) is prevalent in kidney transplant patients. Which level of CMV viral load should be accepted as the gold standard for CMV infection diagnosis is a relatively unsettled issue.

METHODS

Seventy-three kidney transplant patients (mean age = 35.97 ± 14.07 years, 39 male and 34 female) entered this retrospective study. The area under the curve (AUC) of the receiver operative curve (ROC) characteristics was used to define which level of CMV viral load results in the most sensitivity and specificity for different clinical and para clinical parameters differing infected and non-infected patients. Quantitative real-time polymerase chain reaction (TaqMan method) was used for measuring CMV viral load. Written consent was obtained from all patients.

RESULTS

Platelets, compared with the other clinical and para-clinical parameters, had the strongest correlation with CMV viral load in kidney transplant patients (r = -.314, P = .007). There was no correlation between CMV viral load and other laboratory parameters including clinical manifestation. Choosing a threshold of more than 10,000 copies/mL of CMV viral load for defining CMV infection resulted in significance for differing in both white blood cell and platelet count between infected and non-infected patients (AUC = .68, P = .023; AUC = .70, P = .014, respectively).

CONCLUSIONS

Accepting a CMV viral load threshold of more than 10,000 copies/mL as CMV infection has the most sensitivity and specificity for predicting both white blood cell and platelet counts in kidney transplant patients. No CMV viral load threshold as the gold standard for CMV infection diagnosis has the discriminatory power for differing clinical and para-clinical parameters other than platelet and white blood cell count between presumably infected kidney transplant patients and those not infected.

How to develop an in-house real-time quantitative cytomegalovirus polymerase chain reaction: Insights from a cancer centre in Eastern India

Development of a reliable, cost-effective cytomegalovirus quantitative polymerase chain reaction (QPCR) is a priority for developing countries. Manufactured kits are expensive, and availability can be inconsistent. Development of an in-house QPCR kit that is reliable and quality assured requires significant effort and initial investment. However, the rewards of such an enterprise are manifold and include an in-depth understanding of molecular reactions, and expertise in the development of further low-cost molecular kits. The experience of an oncology centre in Eastern India has been shared. Hopefully, this would provide a brief roadmap for such an initiative. Staff with adequate understanding of molecular processes are essential along with vital infrastructure for molecular research and development.

Surveillance of γδ T Cells Predicts Cytomegalovirus Infection Resolution in Kidney Transplants

Cytomegalovirus (CMV) infection in solid-organ transplantation is associated with increased morbidity and mortality, particularly if a CMV mutant strain with antiviral resistance emerges. Monitoring CMV-specific T cell response could provide relevant information for patient care. We and others have shown the involvement of Vδ2(neg) γδ T cells in controlling CMV infection. Here, we assessed if Vδ2(neg) γδ T cell kinetics in peripheral blood predict CMV infection resolution and emergence of a mutant strain in high-risk recipients of kidney transplants, including 168 seronegative recipients receiving organs from seropositive donors (D+R-) and 104 seropositive recipients receiving antithymocyte globulins (R+/ATG). Vδ2(neg) γδ T cell percentages were serially determined in patients grafted between 2003 and 2011. The growing phase of Vδ2(neg) γδ T cells was monitored in each infected patient, and the expansion rate during this phase was estimated individually by a linear mixed model. A Vδ2(neg) γδ T cell expansion rate of ˃0.06% per day predicted the growing phase. The time after infection at which an expansion rate of 0.06% per day occurred was correlated with the resolution of CMV DNAemia (r=0.91; P<0.001). At 49 days of antiviral treatment, Vδ2(neg) γδ T cell expansion onset was associated with recovery, whereas absence of expansion was associated with recurrent disease and DNAemia. The appearance of antiviral-resistant mutant CMV strains was associated with delayed Vδ2(neg) γδ T cell expansion (P<0.001). In conclusion, longitudinal surveillance of Vδ2(neg) γδ T cells in recipients of kidney transplants may predict CMV infection resolution and antiviral drug resistance.

An update on the management and prevention of cytomegalovirus infection following allogeneic hematopoietic stem cell transplantation

ABSTRACT 

A significant progress has been made in deciphering critical aspects of the biology and immunology of CMV infection in the allogeneic stem cell transplantation setting. Genetic traits predisposing to active CMV infection and CMV end-organ disease have begun to be delineated. Reliable molecular assays for CMV DNA load quantitation in body fluids have been developed. Elucidation of immune mechanisms affording control of CMV infection will help to improve the management of active CMV infection. Finally, the advent of new CMV-specific antivirals and promising vaccine prototypes as well as the development of fine procedures for large-scale ex vivo generation of functional CMV-specific T cells for adoptive T cell transfer therapies will certainly minimize the negative impact of CMV on survival in these patients.

Clinical utility of viral load in management of cytomegalovirus infection after solid organ transplantation

The negative impact of cytomegalovirus (CMV) infection on transplant outcomes warrants efforts toward improving its prevention, diagnosis, and treatment. During the last 2 decades, significant breakthroughs in diagnostic virology have facilitated remarkable improvements in CMV disease management. During this period, CMV nucleic acid amplification testing (NAT) evolved to become one of the most commonly performed tests in clinical virology laboratories. NAT provides a means for rapid and sensitive diagnosis of CMV infection in transplant recipients. Viral quantification also introduced several principles of CMV disease management. Specifically, viral load has been utilized (i) for prognostication of CMV disease, (ii) to guide preemptive therapy, (iii) to assess the efficacy of antiviral treatment, (iv) to guide the duration of treatment, and (v) to indicate the risk of clinical relapse or antiviral drug resistance. However, there remain important limitations that require further optimization, including the interassay variability in viral load reporting, which has limited the generation of standardized viral load thresholds for various clinical indications. The recent introduction of an international reference standard should advance the major goal of uniform viral load reporting and interpretation. However, it has also become apparent that other aspects of NAT should be standardized, including sample selection, nucleic acid extraction, amplification, detection, and calibration, among others. This review article synthesizes the vast amount of information on CMV NAT and provides a timely review of the clinical utility of viral load testing in the management of CMV in solid organ transplant recipients. Current limitations are highlighted, and avenues for further research are suggested to optimize the clinical application of NAT in the management of CMV after transplantation.

Quantification of cytomegalovirus viral load

Cytomegalovirus (CMV), a member of the Herpesviridae family, is worldwide distributed. After the primary infection, CMV induces a latent infection with possible reactivation(s). It is responsible for severe to life-threatening diseases in immunocompromised patients and in foetuses and newborns of infected mothers. For monitoring CMV load, classical techniques based on rapid culture or pp65 antigenemia are progressively replaced by quantitative nuclear acid tests (QNAT), easier to implement and standardize. A large variety of QNAT are available from laboratory-developed assays to fully-automated commercial tests. The indications of CMV quantification include CMV infection during pregnancy and in newborns, and viral surveillance of grafted and non-grafted immunocompromised patients, patients with bowel inflammatory diseases and those hospitalised in intensive care unit. A close cooperation between virologists and clinicians is essential for optimizing the benefit of CMV DNA monitoring.

[Large diversity of routine methods used for monitoring human cytomegalovirus infections in France]

Monitoring cytomegalovirus circulating viral load is an important parameter of the follow-up in immunocompromised patients. It can be measured either by DNAemia or by pp65 antigenemia. The French national reference center for cytomegaloviruses organized an investigation of practice in 37 teacher hospital virology laboratories to assess the situation in France in 2010.

METHODS

A questionnaire was sent to collect following information: method used in routine for monitoring of circulating viral load of CMV, assay used, sample matrix and extraction method.

RESULTS

Thirty-six over thirty-seven laboratories filled the questionnaire. Among these, 67% used the quantitative PCR in routine, 11% antigenemia and 22% antigenemia or quantitative PCR; 87% of the laboratories use whole blood for quantitative PCR, whereas 10% and 3% use plasma and leukocytes respectively. Among the laboratories using DNAemia, 100% used real-time PCR assays, 91% use an automated extraction and 9% a manual extraction.

CONCLUSION

Thus in France, measurement of DNAemia by real-time PCR is a tool, which gradually replaces the antigenemia for the monitoring of cytomegalovirus infection among immunocompromised patients. The very great diversity of the methods used justifies the installation of a national quality control on total blood, matrix used by 87% of the laboratories.

Antibody-dependent anti-cytomegalovirus activity of human γδ T cells expressing CD16 (FcγRIIIa)

Human cytomegalovirus (HCMV) infection is an important cause of morbidity and mortality in transplant recipients. Long-term protective immunity against HCMV requires both sustained specific T-cell response and neutralizing IgG production, but the interplay between these effector arms remains poorly defined. We previously demonstrated that γδ T cells play a substantial role as anti-HCMV T-cell effectors. The observation that CD16 (FcγRIIIA) was specifically expressed by the majority of HCMV-induced γδ T cells prompted us to investigate their cooperation with anti-HCMV IgG. We found that CD16 could stimulate γδ T cells independently of T-cell receptor (TCR) engagement and provide them with an intrinsic antibody-dependent cell-mediated cytotoxic (ADCC) potential. Although CD16+γδ T cells did not mediate ADCC against HCMV-infected cells, in accordance with the low level of anti-HCMV IgGs recognizing infected cells, they produced IFNγ when incubated with IgG-opsonized virions. This CD16-induced IFNγ production was greatly enhanced by IL12 and IFNα, 2 cytokines produced during HCMV infection, and conferred to γδ T cells the ability to inhibit HCMV multiplication in vitro. Taken together, these data identify a new antiviral function for γδ T cells through cooperation with anti-HCMV IgG that could contribute to surveillance of HCMV reactivation in transplant recipients.

High incidence of anticytomegalovirus drug resistance among D+R- kidney transplant recipients receiving preemptive therapy

Anti-cytomegalovirus (CMV) prophylaxis is recommended in D+R- kidney transplant recipients (KTR), but is associated with a theoretical increased risk of developing anti-CMV drug resistance. This hypothesis was retested in this study by comparing 32 D+R- KTR who received 3 months prophylaxis (valganciclovir) with 80 D+R- KTR who received preemptive treatment. The incidence of CMV infections was higher in the preemptive group than in the prophylactic group (60% vs. 34%, respectively; p = 0.02). Treatment failure (i.e. a positive DNAemia 8 weeks after the initiation of anti-CMV treatment) was more frequent in the preemptive group (31% vs. 3% in the prophylactic group; p = 0.001). Similarly, anti-CMV drug resistance (UL97 or UL54 mutations) was also more frequent in the preemptive group (16% vs. 3% in the prophylactic group; p = 0.05). Antiviral treatment failures were associated with anti-CMV drug resistance (p = 0.0001). Patients with a CMV load over 5.25 log(10) copies/mL displayed the highest risk of developing anti-CMV drug resistance (OR = 16.91, p = 0.0008). Finally, the 1-year estimated glomerular filtration rate was reduced in patients with anti-CMV drug resistance (p = 0.02). In summary, preemptive therapy in D+R- KTR with high CMV loads and antiviral treatment failure was associated with a high incidence of anti-CMV drug resistance.

Severe steroid-resistant thrombocytopenia secondary to cytomegalovirus infection in an immunocompetent adult

Severe thrombocytopenia secondary to cytomegalovirus (CMV) infection is rare in immunocompetent hosts. We describe a case of severe thrombocytopenia secondary to CMV infection in an immunocompetent 30-year-old man who presented with pyrexia and bleeding tendency. A diagnosis of immune thrombocytopenia (ITP) was made following hematological and serological testing, and bone marrow aspiration. Acute CMV infection was confirmed by serological testing, antigenemia, and detection of CMV-DNA. Corticosteroid therapy was ineffective and intravenous immunoglobulin (IVIG) was therefore administered. This resulted in immediate recovery of the platelet count and cessation of nasal bleeding. Early IVIG administration should be considered in steroid-resistant cases.

The clinical utility of whole blood versus plasma cytomegalovirus viral load assays for monitoring therapeutic response

BACKGROUND

In patients with cytomegalovirus (CMV) disease, regular monitoring of viral loads and treatment until negative are recommended. However, with more sensitive polymerase chain reaction (PCR) assays and cellular peripheral sample types, detection of low-level viremia is achievable. We compared a whole blood real-time PCR with a plasma PCR assay for monitoring therapeutic response.

METHODS

Patients enrolled in a trial to treat CMV disease for 21 days had regular viral load monitoring. The results of a plasma-based PCR assay were compared with a real-time PCR assay of whole blood and assessed for their ability to predict recurrence.

RESULTS

In 219 evaluable patients, viral loads in plasma versus whole blood demonstrated good correlation but significant difference in absolute value and clearance kinetics. Virus was still detectable by day 21 in 154 of 219 (70.3%) patients with the whole blood versus 105 of 219 (52.1%; P<0.001) patients with the plasma assay. The positive predictive value of persistent plasma viremia at day 21 for virologic recurrence was 41.9% vs. 36.3% for the whole blood assay. In the subset of patients with a negative plasma but positive whole blood at day 21 (n = 49), the incidence of virologic recurrence was similar to that of all patients with a negative plasma assay (23.1% vs. 23.6%).

CONCLUSIONS

When treating CMV disease, enhanced detection of residual viremia using a whole blood real-time PCR does not seem to offer significant clinical advantages nor allows for better prediction of recurrence of CMV viremia or disease. The treat-to-negative paradigm may not hold true when such assays are used.

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.

Simultaneous quantification of human herpesvirus 8 DNA by real time PCR in different tissues of HIV infected cuban patients with Kaposi's sarcoma

In Cuba, previous reports have shown an increase of epidemic KS, reaching a total of 120 cases by the end of 2007, despite the use of HAART. To evaluate and compare the role of human herpes virus 8 (HHV-8) viral loads in different compartments of AIDS-related Kaposi's sarcoma (AIDS-KS) patients real-time polymerase chain reaction (RT-PCR) was used to determine the genome copy number of HHV-8 in plasma, saliva, tissue and peripheral blood mononuclear cells (PBMC) of 49 AIDS-KS patients. Overall, 98% of AIDS-KS patients harbored detectable HHV-8. HHV-8 could be detected in 91.6% of KS tissue lesions showing the highest viral load (median log = 3.14 copies/100 ng DNA) followed by saliva and PBMC which were positive in 78%, and 69.2%; respectively. In contrast, HHV-8 was detected in only 37% of plasma samples, which also showed lower viral loads. Men who had sex with men (MSM) were more likely to have three-times higher HHV-8 genome copies in KS lesions when compared with tissues from heterosexuals individuals (OR 3; 95% CI 1.1 to 12.5). These results emphasize the systemic nature of HHV-8-infection and demonstrate the possible role of saliva in HHV-8 transmission among MSM.

[Comparison between the LightCycler CMV Quant Kit (Roche Diagnostics) with a standardized in-house Taqman assay for cytomegalovirus blood viral load quantification]

The broad use of cytomegalovirus (CMV) viral load quantification in blood to follow immunosuppressed patients need standardized assays. Choice of whole blood allows follow-up for several viruses and simplifies pretreatment and storage of samples.

METHODS

We therefore evaluated the LightCycler CMV Quant Kit (Roche Diagnostics) assay on whole blood after a manual extraction (High Pure viral nucleic acid kit, Roche Diagnostics), using as a reference an in-house Taqman assay (LC1UL83) which has been validated in various clinical situations. A panel obtained by serial dilutions of a virion stock in CMV whole blood, a commercial plasma quality control (VQC, Argène, France) crude or diluted in whole blood, infected cells extracts and 46 clinical samples from transplanted patients were tested simultaneously by both techniques.

RESULTS

For plasma quality controls, both PCR assays are correlated VQC (R(2)=0.93). On whole blood or infected cells dilutions, correlation shows an overestimation by the LC1UL83 assay (mean 1.2 log copies/ml) over 3 log though R(2)=0.94. Results with CMV Quant Kit are closer to expected values. Results on clinical samples are close to quality controls with a lower variation of quantification (0.76 log copies/ml).

CONCLUSION

CMV Quant Kit performs well when compared with a clinically validated PCR. Quality control results showed discrepancies between plasma and whole blood, demonstrating the need for whole blood standardized panels to compare the methods. This underlines the need to follow a patient with the same technique during his follow-up.