New Insights Into the Molecular Mechanisms and Immune Control of Cytomegalovirus Reactivation

A novel multiplex real-time PCR assay for the detection of cytomegalovirus, Epstein-Barr virus, herpes simplex virus 1/2 and strategies for application to blood screening

A multiplex real-time PCR has been developed to simultaneously detect transfusion-transmissible pathogens cytomegalovirus, Epstein-Barr virus and herpes simplex virus, as well as to provide sample quality testing, for the conserved regions of the cytomegalovirus UL123 gene, the Epstein-Barr virus BKRF1 gene, and the herpes simplex virus 1/2 UL30 gene, tested on 500 blood donors and 320 transfusion recipients. The laboratory sensitivities for all 3 pathogens were 100 copies/μL. Compared to the commercial real-time PCR reference kit, the multiplex real-time PCR assay for the detection of CMV, EBV and HSV presented 100% consistency. In 820 whole blood samples, the multiplex real-time PCR assay identified 34 (4.15%) positive for CMV DNA, 15 (1.83%) positive for EBV DNA, and 6 (0.73%) positive for HSV DNA. For blood transfusions in high-risk groups, whole blood herpes virus test should be included in the spectrum of pathogen testing for blood donors and recipients.

PCR testing for herpesviruses in aqueous humor samples from patients with and without clinical corneal endothelial graft rejection

To compare prevalence of positive PCR tests for herpesviruses between patients with and without a history of clinical corneal endothelial allograft rejection (AGR). Retrospective cross-sectional study with two-group comparison. A total of 307 aqueous humor (AH) samples from 235 Patients and 244 eyes who underwent penetrating keratoplasty or Descemet membrane endothelial keratoplasty or had a diagnostic AH aspiration due to clinical AGR between 2019 and 2023 were tested for DNA of herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV). PCR test results were compared between the two groups (with/without AGR). Another sub-analysis examined the results of patients without a history of herpetic keratitis. A total of 8% of eyes with clinical AGR (9/108) had a positive PCR result for one of the herpesviruses (HSV:3, CMV:3, EBV:2, VZV:1). All patients in the group without AGR had negative PCR results for all previous viruses (0/136). The difference was statistically significant (p < 0.001). The sub-analysis of eyes without a history of herpetic keratitis also revealed significantly more positive herpes PCR results (7/87) in eyes with AGR than in eyes without AGR (0/42, p = 0.005). Clinical AGR after keratoplasty shows a significant correlation to viral replication. Herpetic infection and AGR could occur simultaneously and act synergistically. Timely differentiation between active herpetic infection and/or AGR is pivotal for proper treatment and graft preservation.

Prevention of Congenital Cytomegalovirus Infection: Review and Case Series of Valaciclovir versus Hyperimmune Globulin Therapy

Cytomegalovirus (CMV) is the most common cause of congenital infections in developed countries because is capable of infecting the fetus after both primary and recurrent maternal infection, and because the virus may be spread for years through infected children. Moreover, CMV is the most serious congenital infection associated with severe neurological and sensorineural sequelae, which can occur at birth or develop later on. Hygienic measures can prevent CMV transmission, which mainly involve contact with children under 3 years of age and attending a nursery or daycare. In animal and human pregnancies, many observational and controlled studies have shown that CMV-specific hyperimmune globulin (HIG) is safe and can significantly decrease maternal-fetal transmission of CMV infection and, mostly, the occurrence of CMV disease. Recently, valaciclovir at the dosage of 8 g/day was also reported to be capable of decreasing the rates of congenital infection and disease. However, comparing the results of our two recent case series, the infants born to women treated with HIG showed significantly lower rates of CMV DNA positivity in urine (9.7% vs. 75.0%; p < 0.0001) and abnormalities after follow-up (0.0% vs. 41.7%; p < 0.0001). The implementation of CMV screening would enable primary prevention via hygiene counseling, improve the understanding and awareness of congenital CMV infection, and increase the knowledge of the potential efficacy of preventive or therapeutic HIG or antiviral administration.

Herpes DNAemia and TTV Viraemia in Intensive Care Unit Critically Ill Patients: A Single-Centre Prospective Longitudinal Study

Introduction

We analysed blood DNAemia of TTV and four herpesviruses (CMV, EBV, HHV6, and HSV-1) in the REAnimation Low Immune Status Marker (REALISM) cohort of critically ill patients who had presented with either sepsis, burns, severe trauma, or major surgery. The aim was to identify common features related to virus and injury-associated pathologies and specific features linking one or several viruses to a particular pathological context.

Methods

Overall and individual viral DNAemia were measured over a month using quantitative PCR assays from the 377 patients in the REALISM cohort. These patients were characterised by clinical outcomes [severity scores, mortality, Intensive Care Unit (ICU)-acquired infection (IAI)] and 48 parameters defining their host response after injury (cell populations, immune functional assays, and biomarkers). Association between viraemic event and clinical outcomes or immune markers was assessed using χ²-test or exact Fisher’s test for qualitative variables and Wilcoxon test for continuous variables.

Results

The cumulative incidence of viral DNAemia increased from below 4% at ICU admission to 35% for each herpesvirus during the first month. EBV, HSV1, HHV6, and CMV were detected in 18%, 12%, 10%, and 9% of patients, respectively. The incidence of high TTV viraemia (>10,000 copies/ml) increased from 11% to 15% during the same period. Herpesvirus viraemia was associated with severity at admission; CMV and HHV6 viraemia correlated with mortality during the first week and over the month. The presence of individual herpesvirus during the first month was significantly associated (p < 0.001) with the occurrence of IAI, whilst herpesvirus DNAemia coupled with high TTV viraemia during the very first week was associated with IAI. Herpesvirus viraemia was associated with a lasting exacerbated host immune response, with concurrent profound immune suppression and hyper inflammation, and delayed return to immune homeostasis. The percentage of patients presenting with herpesvirus DNAemia was significantly higher in sepsis than in all other groups. Primary infection in the hospital and high IL10 levels might favour EBV and CMV reactivation.

Conclusion

In this cohort of ICU patients, phenotypic differences were observed between TTV and herpesviruses DNAemia. The higher prevalence of herpesvirus DNAemia in sepsis hints at further studies that may enable a better in vivo understanding of host determinants of herpesvirus viral reactivation. Furthermore, our data suggest that EBV and TTV may be useful as additional markers to predict clinical deterioration in ICU patients.

Long-Term Evolution of the Adaptive NKG2C+ NK Cell Response to Cytomegalovirus Infection in Kidney Transplantation: An Insight on the Diversity of Host-Pathogen Interaction

Human CMV infection is frequent in kidney transplant recipients (KTR). Pretransplant Ag-specific T cells and adaptive NKG2C⁺ NK cells associate with reduced incidence of infection in CMV⁺ KTR. Expansions of adaptive NKG2C⁺ NK cells were reported in posttransplant CMV-infected KTR. To further explore this issue, NKG2C⁺ NK, CD8⁺, and TcRγδ T cells were analyzed pretransplant and at different time points posttransplant for ≥24 mo in a cohort of CMV⁺ KTR (n = 112), stratified according to CMV viremia detection. In cryopreserved samples from a subgroup (n = 49), adaptive NKG2C⁺ NK cell markers and T cell subsets were compared after a longer follow-up (median, 56 mo), assessing the frequencies of CMV-specific T cells and viremia at the last time point. Increased proportions of NKG2C⁺ NK, CD8⁺, and TcRγδ T cells were detected along posttransplant evolution in viremia(+) KTR. However, the individual magnitude and kinetics of the NKG2C⁺ NK response was variable and only exceptionally detected among viremia(-) KTR, presumably reflecting subclinical viral replication events. NKG2C⁺ expansions were independent of KLRC2 zygosity and associated with higher viral loads at diagnosis; no relation with other clinical parameters was perceived. Increased proportions of adaptive NKG2C⁺ NK cells (CD57⁺, ILT2⁺, FcεRIγ^-) were observed after resolution of viremia long-term posttransplant, coinciding with increased CD8⁺ and Vδ2^- γδ T cells; at that stage CMV-specific T cells were comparable to viremia(-) cases. These data suggest that adaptive NKG2C⁺ NK cells participate with T cells to restore CMV replication control, although their relative contribution cannot be discerned.

The Association Between Previous TORCH Infections and Pregnancy and Neonatal Outcomes in IVF/ICSI-ET: A Retrospective Cohort Study

Objective: This study aimed to investigate the associations between previous TORCH infection (cytomegalovirus, toxoplasmosis, herpes simplex virus, and rubella) with pregnancy and neonatal outcomes in couples undergoing IVF/ICSI-ET. Materials and Methods: A total of 18,074 couples underwent fresh IVF/ICSI-ET (in vitro fertilization/intracytoplasmic sperm injection-embryo transfer) cycles were included in our analyses. TORCH infection status was determined by serological confirmation of cytomegalovirus, toxoplasmosis, herpes simplex virus, and rubella IgG in the absence of IgM antibodies. Clinical pregnancy, ectopic pregnancy, miscarriage, live birth, preterm birth, congenital malformation, and perinatal death were evaluated in both infection and non-infection group. Multivariate logistic regression was applied to calculate odds ratio. Results: Previous toxoplasmosis infection is associated with a significantly decreased preterm birth rate [P = 0.045, OR = 0.755 (95% CI, 0.571-0.997), Adjusted OR = 0.749 (95%CI, 0.566-0.991)]. No differences in clinical pregnancy, ectopic pregnancy, miscarriage, and perinatal death were observed between the corresponding TORCH infection group [IgM (-) IgG(+)] and the non-infection group [IgM (-) IgG (-)]. Conclusions: Previous TORCH infections were not associated with adverse pregnancy and neonatal outcomes in IVF/ICSI-ET overall, and toxoplasmosis infection might be associated with a lower preterm birth rate in patients underwent IVF/ICSI-ET. The necessity of TORCH IgG screening in IVF procedure might need re-evaluation, and further cost-effective analysis might be helpful for the clinical management strategy.