An Elastin-like Polypeptide-fusion peptide targeting capsid-tegument interface as an antiviral against cytomegalovirus infection.

The tegument protein pp150 of Human Cytomegalovirus (HCMV) is known to be essential for the final stages of virus maturation and mediates its functions by interacting with capsid proteins. Our laboratory has previously identified the critical regions in pp150 important for pp150-capsid interactions and designed peptides similar in sequence to these regions, with a goal to competitively inhibit capsid maturation. Treatment with a specific peptide (PepCR2 or P10) targeted to pp150 conserved region 2 led to a significant reduction in murine CMV (MCMV) growth in cell culture, paving the way for in vivo testing in a mouse model of CMV infection. However, the general pharmacokinetic parameters of peptides, including rapid degradation and limited tissue and cell membrane permeability, pose a challenge to their successful use in vivo. Therefore, we designed a biopolymer-stabilized elastin-like polypeptide (ELP) fusion construct (ELP-P10) to enhance the bioavailability of P10. Antiviral efficacy and cytotoxic effects of ELP-P10 were studied in cell culture, and pharmacokinetics, biodistribution, and antiviral efficacy were studied in a mouse model of CMV infection. ELP-P10 maintained significant antiviral activity in cell culture, and this conjugation significantly enhanced P10 bioavailability in mouse tissues. The fluorescently labeled ELP-P10 accumulated to higher levels in mouse liver and kidneys as compared to the unconjugated P10. Moreover, viral titers from vital organs of MCMV-infected mice indicated a significant reduction of virus load upon ELP-P10 treatment. Therefore, ELP-P10 has the potential to be developed into an effective antiviral against CMV infection.

Comparison of Whole Blood and Plasma for Monitoring Cytomegalovirus and Epstein-Barr Virus.

Monitoring Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection after transplantation is recommended to enable preemptive therapy. However, the most suitable sample type remains unclear. Patients who underwent hematopoietic stem cell or liver transplantation were included in this study. Viral loads in sequential whole-blood and plasma samples were retrospectively analyzed. EBV DNA was detected more frequently in whole blood (55%) than in plasma (18%). The detection rate of CMV DNA was similar between the two sample types. The correlation of viral loads between the two sample types were 0.515 and 0.688 for EBV and CMV, respectively. Among paired samples in which EBV DNA was detected in whole blood, the plasma EBV detection rate was significantly higher in patients who underwent hematopoietic stem cell transplantation than in those who underwent liver transplantation. The viral DNA load in whole blood and plasma showed similar trends. The EBV detection rate was higher in whole blood, and a high correlation was observed between CMV DNA loads and whole blood and plasma. These results indicate that whole blood is more sensitive for monitoring both EBV and CMV, whereas plasma is a potential alternative sample for monitoring CMV.

Adequate antiviral treatment lowers overall complications of cytomegalovirus colitis among inpatients with inflammatory bowel diseases.

BACKGROUND: Cytomegalovirus (CMV) colitis significantly complicates the course of inflammatory bowel disease (IBD), frequently leading to severe flare-ups and poor outcomes. The role of antiviral therapy in hospitalized IBD patients with CMV colitis is currently under debate. This retrospective analysis seeks to clarify the influence of antiviral treatment on these patients. METHODS: We retrospectively reviewed IBD patients diagnosed with CMV colitis via immunohistochemistry staining from colonic biopsies at a major tertiary center from January 2000 to May 2021. The study focused on patient demographics, clinical features, risk factors, prognostic indicators, and antiviral treatment outcomes. RESULTS: Among 118 inpatients, 42 had CMV colitis. Risk factors included hypoalbuminemia and antibiotic use. IBD patients with CMV colitis receiving < 14 days of antiviral therapy had higher complication (72% vs. 43%, p = 0.028) and surgery rates (56% vs. 26%, p = 0.017) compared to those without CMV. Adequate antiviral therapy (≥ 14 days) significantly reduced complications in the CMV group (29% vs. 72%, p = 0.006), especially in Crohn's disease (20% vs. 100%, p = 0.015). Independent predictors of IBD-related complications were CMV colitis (Odds Ratio [OR] 3.532, 90% Confidence Interval [CI] 1.012-12.331, p = 0.048), biological treatment failure (OR 4.953, 95% CI 1.91-12.842, p = 0.001), and adequate antiviral therapy (OR 0.108, 95% CI 0.023-0.512, p = 0.005). CONCLUSION: CMV colitis and a history of biological treatment failure increase complication risks in IBD patients. Adequate antiviral therapy significantly mitigates these risks, highlighting its importance in managing IBD patients with CMV colitis.

Lingering Effects of Early Institutional Rearing and Cytomegalovirus Infection on the Natural Killer Cell Repertoire of Adopted Adolescents.

Adversity during infancy can affect neurobehavioral development and perturb the maturation of physiological systems. Dysregulated immune and inflammatory responses contribute to many of the later effects on health. Whether normalization can occur following a transition to more nurturing, benevolent conditions is unclear. To assess the potential for recovery, blood samples were obtained from 45 adolescents adopted by supportive families after impoverished infancies in institutional settings (post-institutionalized, PI). Their immune profiles were compared to 39 age-matched controls raised by their biological parents (non-adopted, NA). Leukocytes were immunophenotyped, and this analysis focuses on natural killer (NK) cell populations in circulation. Cytomegalovirus (CMV) seropositivity was evaluated to determine if early infection contributed to the impact of an atypical rearing. Associations with tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), two cytokines released by activated NK cells, were examined. Compared to the NA controls, PI adolescents had a lower percent of CD56bright NK cells in circulation, higher TNF-α levels, and were more likely to be infected with CMV. PI adolescents who were latent carriers of CMV expressed NKG2C and CD57 surface markers on more NK cells, including CD56dim lineages. The NK cell repertoire revealed lingering immune effects of early rearing while still maintaining an overall integrity and resilience.

Non-Detection of HCMV Total Genomic DNA in Human Glioma Cells Genome.

AIM: To demonstrate if the human cytomegalovirus (HCMV) genome, that is involved in the pathogenesis of gliomas, is part of the genomic DNA of glioma cells or not. MATERIAL AND METHODS: The study included U87MG glioblastoma cell culture and tumor samples from glioma patients. The genomic DNA of tumor samples and U87MG cells were extracted and real-time quantitative PCR was used to assess the presence of the human cytomegalovirus genomic DNA. RESULTS: Consequently, HCMV positivity was not detected in the tumor and cell line genomic DNA under the aforementioned experimental conditions. CONCLUSION: We found that the genomic DNA of all the samples was negative for HCMV genomic DNA. Thus, HCMV could not be detected in human glioma tumors and we put forward that HCMV genomic DNA was not incorporated into the genomic DNA of glioma cells. Thus, total viral DNA is not involved in the pathogenesis of glioma; however, small viral particles or specific genes might be incorporated into the genomic DNA of glioma cells, leading to cancer development. This prompts further studies for verification.

Mesenchymal Stem Cell-Derived Exosomes Attenuate Murine Cytomegalovirus-Infected Pneumonia via NF-κB/NLRP3 Signaling Pathway.

Reactivation and infection with cytomegalovirus (CMV) are frequently observed in recipients of solid organ transplants, bone marrow transplants, and individuals with HIV infection. This presents an increasing risk of allograft rejection, opportunistic infection, graft failure, and patient mortality. Among immunocompromised hosts, interstitial pneumonia is the most critical clinical manifestation of CMV infection. Recent studies have demonstrated the potential therapeutic benefits of exosomes derived from mesenchymal stem cells (MSC-exos) in preclinical models of acute lung injury, including pneumonia, ARDS, and sepsis. However, the role of MSC-exos in the pathogenesis of infectious viral diseases, such as CMV pneumonia, remains unclear. In a mouse model of murine CMV-induced pneumonia, we observed that intravenous administration of mouse MSC (mMSC)-exos reduced lung damage, decreased the hyperinflammatory response, and shifted macrophage polarization from the M1 to the M2 phenotype. Treatment with mMSC-exos also significantly reduced the infiltration of inflammatory cells and pulmonary fibrosis. Furthermore, in vitro studies revealed that mMSC-exos reversed the hyperinflammatory phenotype of bone marrow-derived macrophages infected with murine CMV. Mechanistically, mMSC-exos treatment decreased activation of the NF-κB/NLRP3 signaling pathway both in vivo and in vitro. In summary, our findings indicate that mMSC-exo treatment is effective in severe CMV pneumonia by reducing lung inflammation and fibrosis through the NF-κB/NLRP3 signaling pathway, thus providing promising therapeutic potential for clinical CMV infection.

The association of Torque Teno viral load with CMV and BKV infection in pediatric and adolescent kidney transplant patients.

BACKGROUND: Long-term allograft and patient survival after kidney transplantation (KTX) depends on the balance between over- and under-immunosuppression (IS). High levels of IS predispose to opportunistic infections. Plasma load of Torque Teno Virus (TTV), a non-pathogenic highly prevalent Annellovirus, is associated with its hosts immune status, especially after solid organ transplantation. OBJECTIVES: To investigate the association of plasma TTV load and opportunistic viral infections after pediatric KTX. STUDY DESIGN: This retrospective study includes all pediatric KTX patients followed at the Medical University of Vienna 2014-2020. PCR for Cytomegalovirus (CMV), Epstein-Barr virus (EBV), BK virus (BKV), and TTV was performed every 4-8 weeks at routine follow-up visits. RESULTS: 71 pediatric KTX patients were followed with TTV measurements for a median of 2.7 years. TTV plasma load was associated with CMV DNAemia at the next visit with an OR of 2.37 (95 % CI 1.15-4.87; p = 0.03) after adjustment for time after KTX and recipient age. For a cut-off of 7.68 log10 c/mL TTV a sensitivity of 100 %, a specificity of 61 %, a NPV 100 %, and a PPV of 46 % to detect CMV DNAemia at the next visit was calculated. TTV plasma loads were also associated with BKV DNAuria and BKV DNAemia at the next visit, but not with EBV DNAemia. CONCLUSIONS: This is the first study to analyse associations between TTV plasma loads and opportunistic viral infections in pediatric KTX. We were able to present a TTV cut-off for the prediction of clinically relevant CMV DNAemia that might be useful in clinical care.

Monitoring Porcine Cytomegalovirus in Both Donors and Recipients is Crucial for Recipient's Survival in Pig-to-Cynomolgus Xenotransplantation.

BACKGROUND: Xenotransplantation, particularly when involving pig donors, presents challenges related to the transmission of porcine cytomegalovirus (pCMV) and its potential impact on recipient outcomes. This study aimed to investigate the relationship between pCMV positivity in both donors and recipients and the survival time of cynomolgus monkey recipients after xenogeneic kidney transplantation. METHODS: We conducted 20 cynomolgus xenotransplants using 18 transgenic pigs. On the surgery day, donor pig blood was sampled, and DNA was extracted from serum and peripheral blood mononuclear cells. Recipient DNA extraction followed the same protocol from pre-transplantation to post-transplantation. Porcine cytomegalovirus detection used real-time polymerase chain reaction (real-time PCR) with the ViroReal kit, achieving a sensitivity of 50 copies/reaction. A Ct value of 37.0 was the pCMV positivity threshold. RESULTS: Of 20 cynomolgus recipients, when donors tested negative for pCMV, recipients also showed negative results in 9 cases. In 4 cases where donors were negative, recipients tested positive. All 5 cases with pCMV-positive donors resulted in positive assessments for recipients. Detection of donor pCMV correlated with shorter recipient survival. Continuous recipient positivity during observation correlated with shorter survival, whereas transient detection showed no significant change in survival rates. However, donor pig phenotypes and transplantation protocols did not significantly impact survival. CONCLUSION: The detection of pCMV in both donors and recipients plays a crucial role in xenotransplantation outcomes. These findings suggest the importance of monitoring and managing pCMV in xenotransplantation to enhance long-term outcomes.

Antiviral activity of immunosuppressors alone and in combination against human adenovirus and cytomegalovirus.

Human adenovirus (HAdV) and cytomegalovirus (HCMV) cause high morbidity and mortality in patients undergoing solid organ transplantation (SOT) and haematopoietic stem cell transplantation (HSCT). Immunosuppressors are used universally to prevent graft-vs-host disease in HSCT and graft rejection in SOT. The long-term use of these drugs is associated with a high risk of infection, but there is also evidence of their specific interference with viral infection. This study evaluated the antiviral activity of immunosuppressors commonly used in clinical practice in SOT and HSCT recipients in vitro to determine whether their use could be associated with reduced risk of HAdV and HCMV infection. Cyclophosphamide, tacrolimus, cyclosporine, mycophenolic acid, methotrexate, everolimus and sirolimus presented antiviral activity, with 50% inhibitory concentration (IC50) values at low micromolar and sub-micromolar concentrations. Mycophenolic acid and methotrexate showed the greatest antiviral effects against HAdV (IC50=0.05 µM and 0.3 µM, respectively) and HCMV (IC50=10.8 µM and 0.02 µM, respectively). The combination of tacrolimus and mycophenolic acid showed strong synergistic antiviral activity against both viruses, with combinatory indexes (CI50) of 0.02 and 0.25, respectively. Additionally, mycophenolic acid plus cyclosporine, and mycophenolic acid plus everolimus/sirolimus showed synergistic antiviral activity against HAdV (CI50=0.05 and 0.09, respectively), while methotrexate plus cyclosporine showed synergistic antiviral activity against HCMV (CI50=0.29). These results, showing antiviral activity in vitro against both HAdV and HCMV, at concentrations below the human Cmax values, may be relevant for the selection of specific immunosuppressant therapies in patients at risk of HAdV and HCMV infections.

Human cytomegalovirus modulates mTORC1 to redirect mRNA translation within quiescently infected monocytes.

Human cytomegalovirus (HCMV) utilizes peripheral blood monocytes as a means to systemically disseminate throughout the host. Following viral entry, HCMV stimulates non-canonical Akt signaling leading to the activation of mTORC1 and the subsequent translation of select antiapoptotic proteins within infected monocytes. However, the full extent to which the HCMV-initiated Akt/mTORC1 signaling axis reshapes the monocyte translatome is unclear. We found HCMV entry alone was able to stimulate widescale changes to mRNA translation levels and that inhibition of mTOR, a component of mTORC1, dramatically attenuated HCMV-induced protein synthesis. Although monocytes treated with normal myeloid growth factors also exhibited increased levels of translation, mTOR inhibition had no effect, suggesting HCMV activation of mTOR stimulates the acquisition of a unique translatome within infected monocytes. Indeed, polyribosomal profiling of HCMV-infected monocytes identified distinct prosurvival transcripts that were preferentially loaded with ribosomes when compared to growth factor-treated cells. Sirtuin 1 (SIRT1), a deacetylase that exerts prosurvival effects through regulation of the PI3K/Akt pathway, was found to be highly enriched following HCMV infection in an mTOR-dependent manner. Importantly, SIRT1 inhibition led to the death of HCMV-infected monocytes while having minimal effect on uninfected cells. SIRT1 also supported a positive feedback loop to sustain Akt/mTORC1 signaling following viral entry. Taken together, HCMV profoundly reshapes mRNA translation in an mTOR-dependent manner to enhance the synthesis of select factors necessary for the survival of infected monocytes.IMPORTANCEHuman cytomegalovirus (HCMV) infection is a significant cause of morbidity and mortality among the immunonaïve and immunocompromised. Peripheral blood monocytes are a major cell type responsible for disseminating the virus from the initial site of infection. In order for monocytes to mediate viral spread within the host, HCMV must subvert the naturally short lifespan of these cells. In this study, we performed polysomal profiling analysis, which demonstrated HCMV to globally redirect mRNA translation toward the synthesis of cellular prosurvival factors within infected monocytes. Specifically, HCMV entry into monocytes induced the translation of cellular SIRT1 to generate an antiapoptotic state. Defining the precise mechanisms through which HCMV stimulates survival will provide insight into novel anti-HCMV drugs able to target infected monocytes.

Letermovir vs Valganciclovir for Prophylaxis of Cytomegalovirus in High-Risk Kidney Transplant Recipients: A Randomized Clinical Trial.

Importance: Valganciclovir for 200 days is standard care for cytomegalovirus (CMV) prophylaxis in high-risk CMV-seronegative kidney transplant recipients who receive an organ from a CMV-seropositive donor, but its use is limited by myelosuppression. Objective: To compare the efficacy and safety of letermovir with valganciclovir for prevention of CMV disease in CMV-seronegative kidney transplant recipients who receive an organ from a CMV-seropositive donor. Design, Setting, and Participants: Randomized, double-masked, double-dummy, noninferiority, phase 3 trial in adult CMV-seronegative kidney transplant recipients who received an organ from a CMV-seropositive donor at 94 participating sites between May 2018 and April 2021 (final follow-up in April 2022). Interventions: Participants were randomized in a 1:1 ratio (stratified by receipt of lymphocyte-depleting induction immunosuppression) to receive letermovir, 480 mg, orally daily (with acyclovir) or valganciclovir, 900 mg, orally daily (adjusted for kidney function) for up to 200 days after transplant, with matching placebos. Main Outcomes and Measures: The primary outcome was CMV disease, confirmed by an independent masked adjudication committee, through posttransplant week 52 (prespecified noninferiority margin, 10%). CMV disease through week 28 and time to onset of CMV disease through week 52 were secondary outcomes. Exploratory outcomes included quantifiable CMV DNAemia and resistance. The rate of leukopenia or neutropenia through week 28 was a prespecified safety outcome. Results: Among 601 participants randomized, 589 received at least 1 dose of the study drug (mean age, 49.6 years; 422 [71.6%] men). Letermovir (n = 289) was noninferior to valganciclovir (n = 297) for prevention of CMV disease through week 52 (10.4% vs 11.8% of participants with committee-confirmed CMV disease; stratum-adjusted difference -1.4% [95% CI, -6.5% to 3.8%]). No participants who received letermovir vs 5 participants (1.7%) who received valganciclovir developed CMV disease through week 28. Time to onset of CMV disease was comparable between the groups (hazard ratio, 0.90 [95% CI, 0.56-1.47]). Quantifiable CMV DNAemia was detected in 2.1% of participants in the letermovir group vs 8.8% in the valganciclovir group by week 28. Of participants evaluated for suspected CMV disease or CMV DNAemia, none (0/52) who received letermovir and 12.1% (8/66) who received valganciclovir had resistance-associated substitutions. The rate of leukopenia or neutropenia through week 28 was lower with letermovir vs valganciclovir (26% vs 64%; difference, -37.9% [95% CI, -45.1% to -30.3%]; P < .001). Fewer participants in the letermovir group than the valganciclovir group discontinued prophylaxis due to adverse events (4.1% vs 13.5%) or drug-related adverse events (2.7% vs 8.8%). Conclusion and Relevance: Among adult CMV-seronegative kidney transplant recipients who received an organ from a CMV-seropositive donor, letermovir was noninferior to valganciclovir for prophylaxis of CMV disease over 52 weeks, with lower rates of leukopenia or neutropenia, supporting its use for this indication. Trial Registration: ClinicalTrials.gov Identifier: NCT03443869; EudraCT: 2017-001055-30.

Rethinking human cytomegalovirus latency reservoir.

Human cytomegalovirus (HCMV) is a prevalent herpesvirus, infecting the majority of the human population. Like other herpesviruses, it causes lifelong infection through the establishment of latency. Although reactivation from latency can cause significant morbidity and mortality in immunocompromised hosts, our understanding of HCMV latency and how it is maintained remains limited. Here, we discuss the characterized latency reservoir in hematopoietic cells in the bone marrow and the gaps in our knowledge of mechanisms that facilitate HCMV genome maintenance in dividing cells. We further review clinical evidence that strongly suggests the tissue origin of HCMV reactivation, and we outline similarities to murine cytomegalovirus where latency in tissue-resident cells has been demonstrated. Overall, we think these observations call for a rethinking of HCMV latency reservoirs and point to potential sources of HCMV latency that reside in tissues.

Endothelial Cell Infection by Guinea Pig Cytomegalovirus Is a Lytic or Persistent Infection Depending on Tissue Origin but Requires Viral Pentamer Complex and pp65 Tegument Protein.

The guinea pig is the only small animal model for congenital cytomegalovirus (CMV) but requires species-specific guinea pig cytomegalovirus (GPCMV). Infection of epithelial cells and trophoblasts by GPCMV requires the viral glycoprotein pentamer complex (PC) and endocytic entry because of the absence of platelet-derived growth factor receptor alpha (PDGFRA). Endothelial cells represent an important cell type for infection, dissemination in the host, and disease but have been poorly evaluated for GPCMV. Novel endothelial cell lines were established from animal vascular systems, including aorta (EndoC) and placental umbilical cord vein (GPUVEC). Cell lines were characterized for endothelial cell protein markers (PECAM1, vWF, and FLI1) and evaluated for GPCMV infection. Only PC-positive virus was capable of infecting endothelial cells. Individual knockout mutants for unique PC components (GP129, GP131, and GP133) were unable to infect endothelial cells without impacting fibroblast infection. Ectopic expression of PDGFRA in EndoC cells enabled GPCMV(PC-) infection via direct cell entry independent of the PC. Neutralizing antibodies to the essential viral gB glycoprotein were insufficient to prevent endothelial cell infection, which also required antibodies to gH/gL and the PC. Endothelial cell infection was also dependent upon viral tegument pp65 protein (GP83) to counteract the IFI16/cGAS-STING innate immune pathway, similar to epithelial cell infection. GPCMV endothelial cells were lytically (EndoC) or persistently (GPUVEC) infected dependent on tissue origin. The ability to establish a persistent infection in the umbilical cord could potentially enable sustained and more significant infection of the fetus in utero. Overall, results demonstrate the importance of this translationally relevant model for CMV research. IMPORTANCE Congenital CMV is a leading cause of cognitive impairment and deafness in newborns, and a vaccine is a high priority. The only small animal model for congenital CMV is the guinea pig and guinea pig cytomegalovirus (GPCMV) encoding functional HCMV homolog viral glycoprotein complexes necessary for cell entry that are neutralizing-antibody vaccine targets. Endothelial cells are important in HCMV for human disease and viral dissemination. GPCMV endothelial cell infection requires the viral pentamer complex (PC), which further increases the importance of this complex as a vaccine target, as antibodies to the immunodominant and essential viral glycoprotein gB fail to prevent endothelial cell infection. GPCMV endothelial cell infection established either a fully lytic or a persistent infection, depending on tissue origin. The potential for persistent infection in the umbilical cord potentially enables sustained infection of the fetus in utero, likely increasing the severity of congenital disease.

Cytomegalovirus cell tropism and clinicopathological characteristics in gastrointestinal tract of patients with HIV/AIDS.

BACKGROUND: Cytomegalovirus (CMV) has been recognized as one of the frequently occurring opportunistic infections (OIs) reported in the patients having human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). In addition, it has been identified as the factor leading to gastrointestinal (GI) tract disorder among HIV/AIDS population. CMV exhibits broad cell tropism in different organs. This study evaluated the CMV cell tropism and clinicopathological characteristics of CMV infection in the different GI regions in HIV/AIDS cases. METHODS: Using nucleic acid in situ hybridization (ISH), CMV was detected in the gastrointestinal mucosal biopsy samples. The paraffin-embedded samples were stained with hematoxylin and eosin (HE) and immunohistochemistry (IHC), respectively. RESULTS: A total of 32 HIV/AIDS patients were enrolled in this study. Fourteen of these patients underwent gastroscopy, while the remaining eighteen received colonoscopy. CMV-infected cells were observed at 46 GI sites. Among them, the colon was the region with the highest susceptibility to GI CMV infection (n = 12, 26.1%). The CMV giant cell inclusion bodies were detected in epithelial cells and mesenchymal cells, including histiocytes, smooth muscle cells, fibroblasts, and endothelial cells. In the duodenum, there were markedly more positive epithelial cells than mesenchymal cells (p = 0.033). In contrast, in the esophagus (p = 0.030), cardia (p = 0.003), rectum (p = 0.019), colon (p < 0.001), and cecum (p < 0.001), there were notably less positive epithelial cells than mesenchymal cells. The expression levels of PDGFRα and Nrp2 in the mesenchymal cells were higher than the epithelial cells in cardia, cecum, colon, sigmoid, and rectum, especially in the areas with ulcers. However, Nrp2 in the epithelial cells was higher than that in the duodenum. Moreover, the positive CMV DNA in peripheral blood was related to the CMV-positive cell count, as well as the ulceration in GI tract (p = 0.035 and 0.036, respectively). CONCLUSIONS: The colon has been identified as the GI site with the highest susceptibility to CMV infection. There are different CMV-infected cells in the different sites of the GI that relate to the expression level of PDGFRα and Nrp2. CMV DNA positive in the blood is related to the positive CMV cell count, as well as ulceration in the GI tract.

Metabolic Reprogramming of Glioblastoma Cells during HCMV Infection Induces Secretome-Mediated Paracrine Effects in the Microenvironment.

Glioblastoma (GBM) is an aggressive primary central nervous system neoplasia with limited therapeutic options and poor prognosis. Following reports of cytomegalovirus (HCMV) in GBM tumors, the anti-viral drug Valganciclovir was administered and found to significantly increase the longevity of GBM patients. While these findings suggest a role for HCMV in GBM, the relationship between them is not clear and remains controversial. Treatment with anti-viral drugs may prove clinically useful; however, their results do not explain the underlying mechanism between HCMV infection and GBM progression. We hypothesized that HCMV infection would metabolically reprogram GBM cells and that these changes would allow for increased tumor progression. We infected LN-18 GBM cells and employed a Seahorse Bioanalyzer to characterize cellular metabolism. Increased mitochondrial respiration and glycolytic rates were observed following infection. These changes were accompanied by elevated production of reactive oxygen species and lactate. Due to lactate's numerous tumor-promoting effects, we examined the impact of paracrine signaling of HCMV-infected GBM cells on uninfected stromal cells. Our results indicated that, independent of viral transmission, the secretome of HCMV-infected GBM cells was able to alter the expression of key metabolic proteins and epigenetic markers. This suggests a mechanism of action where reprogramming of GBM cells alters the surrounding tumor microenvironment to be permissive to tumor progression in a manner akin to the Reverse-Warburg Effect. Overall, this suggests a potential oncomodulatory role for HCMV in the context of GBM.

Donor NKG2C homozygosity contributes to CMV clearance after haploidentical transplantation.

CMV infection remains an important cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Several investigators have reported that adaptive NKG2C+ NK cells persistently expand during CMV reactivation. In our study, 2 cohorts were enrolled to explore the relationships among the NKG2C genotype, NKG2C+ NK cell reconstitution, and CMV infection. Multivariate analysis showed that donor NKG2C gene deletion was an independent prognostic factor for CMV reactivation and refractory CMV reactivation. Furthermore, adaptive NKG2C+ NK cells' quantitative and qualitative reconstitution, along with their anti-CMV function after transplantation, was significantly lower in patients grafted with NKG2Cwt/del donor cells than in those grafted with NKG2Cwt/wt donor cells. At day 30 after transplantation, quantitative reconstitution of NKG2C+ NK cells was significantly lower in patients with treatment-refractory CMV reactivation than in patients without CMV reactivation and those with nonrefractory CMV reactivation. In humanized CMV-infected mice, we found that, compared with those from NKG2Cwt/del donors, adaptive NKG2C+ NK cells from NKG2Cwt/wt donors induced earlier and stronger expansion of NKG2C+ NK cells as well as earlier and stronger CMV clearance in vivo. In conclusion, donor NKG2C homozygosity contributes to CMV clearance by promoting the quantitative and qualitative reconstruction of adaptive NKG2C+ NK cells after haploidentical allo-HSCT.

Incidence of refractory cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation.

Post-transplant cytomegalovirus (CMV) disease can be almost completely avoided by current infection control procedures. However, CMV reactivation occurs in more than half of patients, and some patients can develop clinically resistant CMV infections. Whether resistance is due to the host's immune status or a viral resistance mutation is challenging to confirm. Therefore, a prospective observational analysis of refractory CMV infection was conducted in 199 consecutive patients who received allogeneic hematopoietic stem cell transplantation at a single institution. Among them, 143 (72%) patients received anti-CMV drugs due to CMV reactivation, and only 17 (8.5%) exhibited refractory CMV infection. These patients had clinically refractory infection. However, viral genome analysis revealed that only one patient exhibited a mutation associated with the anti-CMV drug resistance. Clinical resistance was mainly correlated with host immune factors, and the incidence of resistance caused by gene mutations was low at the early stage after a transplantation.

Exposure-Response Analyses of Letermovir Following Oral and Intravenous Administration in Allogeneic Hematopoietic Cell Transplantation Recipients.

The cytomegalovirus (CMV) viral terminase inhibitor letermovir is approved for prophylaxis of CMV infection and disease in adult CMV-seropositive allogeneic hematopoietic stem cell transplantation recipients. In a phase III trial (NCT02137772), letermovir significantly reduced clinically significant CMV infection (CS-CMVi) rate vs. placebo through Week 24 (primary end point) and Week 14 (secondary end point) post transplantation. Here, exposure-response relationships were investigated using efficacy and selected safety end points from the phase III trial to inform the proposed clinical dose. Post hoc exposure estimates were derived from a population pharmacokinetic model. No significant exposure dependencies were found for CS-CMVi through Week 24 or Week 14 among letermovir-treated participants. Evaluated covariates had no impact on exposure-efficacy relationships and letermovir plasma exposure did not affect time of CS-CMVi onset. There was no dependence between adverse event incidence and letermovir exposure. These results support current dosing recommendations in several countries and regions, including the United States and European Union.

Emerging Mechanisms of G1/S Cell Cycle Control by Human and Mouse Cytomegaloviruses.

Cytomegaloviruses (CMVs) are among the largest pathogenic viruses in mammals. To enable replication of their long double-stranded DNA genomes, CMVs induce profound changes in cell cycle regulation. A hallmark of CMV cell cycle control is the establishment of an unusual cell cycle arrest at the G1/S transition, which is characterized by the coexistence of cell cycle stimulatory and inhibitory activities. While CMVs interfere with cellular DNA synthesis and cell division, they activate S-phase-specific gene expression and nucleotide metabolism. This is facilitated by a set of CMV gene products that target master regulators of G1/S progression such as cyclin E and A kinases, Rb-E2F transcription factors, p53-p21 checkpoint proteins, the APC/C ubiquitin ligase, and the nucleotide hydrolase SAMHD1. While the major themes of cell cycle regulation are well conserved between human and murine CMVs (HCMV and MCMV), there are considerable differences at the level of viral cell cycle effectors and their mechanisms of action. Furthermore, both viruses have evolved unique mechanisms to sense the host cell cycle state and modulate the infection program accordingly. This review provides an overview of conserved and divergent features of G1/S control by MCMV and HCMV.