Immunobiology of human cytomegalovirus: From bench to bedside. Clin Microbiol Rev. 2009;22:76-98, Table of Contents. [PMID: 19136435 DOI: 10.1128/cmr.00034-08]

Prevalence and investigation of Cytomegalovirus (HCMV) in blood donors from the main blood establishment in Rio de Janeiro/Brazil

BACKGROUND

Human Cytomegalovirus (HCMV) remains a significant cause of morbidity and mortality among pregnant women and immunocompromised patients. HCMV transmission can occur through blood transfusions and typically results in asymptomatic infections in newborns and young individuals or causes symptoms like infectious mononucleosis when symptomatic infections arise. HCMV infection poses a notable risk to transfusion recipients, particularly in vulnerable groups such as premature newborns and immunosuppressed patients. The risk persists even after prophylaxis ends, especially in patients who undergo organ transplantation and receive blood or blood products from a seropositive donor while being seronegative themselves (D+/R-).

MATERIALS AND METHODS

Here, we investigated the serological and molecular prevalence of HCMV among 980 blood donors from the main blood bank in Rio de Janeiro, Brazil, using chemiluminescence and real-time PCR (TaqMan). The data underwent univariate, bivariate, and multivariate statistical analyses using the SPSS program, version 20.0.

RESULTS

The average age of donors was 38.53 years, with a majority being male (53.9 %). The prevalence of cytomegalovirus was 88.5 %, and HCMV DNA was detected in 1.2 % of the samples.

DISCUSSION

Given that there are approximately 100,000 blood donations per year, this prevalence rate is considerably high compared to that in developed countries. These findings underscore the critical need for ongoing surveillance and molecular testing to ensure the safety of blood supplies.

Infectious agents in the pathogenesis of autoimmune rheumatic diseases

Autoimmune rheumatic diseases (AIRDs) are diseases with complex outset and courses, in which both genetic and environmental factors participate. Many environmental factors can be committed to AIRDs outset and development. The most popular of them, with confirmed impact, are smoking, age, gender, and microorganisms. In light of recent research an assumption about the importance of various microorganisms in the pathogenesis of AIRDs is growing in popularity. The human immune system has various protective mechanisms against infectious antigens which in normal cases let organism manage potential infection faster and more effectively. Unfortunately in some situations, specific errors in those mechanisms can cause an autoreactive response despite mitigation of infection. Viruses including EBV, CMV, and even SARS-CoV2 can cause these errors. This in combination with genetic factors can lead to rheumatic disease development. This research aims to provide a brief review of the role of viruses in the outset and development of AIRDs.

Discordance between humoral and cellular immune responses to cytomegalovirus infection in CMV seropositive patients awaiting lung transplantation

Introduction

Risk stratification for CMV infection in lung transplantation (LT) currently relies on determining donor and recipient CMV IgG before transplantation. However, it has been observed that some patients who test positive for CMV-specific humoral response before kidney transplantation (KT) exhibit a weak or absent CMV-specific cellular response. The significance of this observation in LT is still unknown.

Methods

This prospective, multicenter, observational study evaluated the agreement between CMV IgG serology and specific cell-mediated response (specific T cell Enzyme-Linked ImmunoSpot Assay, ELISPOT, against CMV pp65 and IE-1 antigens) in 121 patients on the waiting list for LT.

Results

One hundred and four (86%) patients were seropositive for CMV. Discordant humoral and cellular immunologic responses were observed, 29% of seropositive patients had a weak ELISPOT response to IE-1 and 39% to pp65. In 22% of seropositive patients, there was a weak or no response to both antigens. All seronegative patients did not respond to either antigen.

Conclusions

Therefore, over 20% of CMV seropositive LT candidates showed weak CMV-specific cellular immune responses despite detectable serological memory against CMV. This may be important in assessing the risk of developing a CMV infection after transplantation.

Inherited metabolic diseases are a potent risk factor for cytomegalovirus infection in pediatric living donor liver transplantation

BACKGROUND

Cytomegalovirus (CMV) is a major infectious complication in solid-organ transplant recipients, particularly in the context of pediatric liver transplantation. CMV serostatus is a well-established risk factor for postoperative CMV infection, with CMV seronegative recipients who receive organs from seropositive donors (D+/R-) being at the highest risk. Our previous research indicated a higher incidence of CMV infection in recipients with inherited metabolic diseases (IMDs) compared with those with biliary atresia (BA). This study aimed to determine whether IMDs constitute an independent risk factor for postoperative CMV infection.

METHODS

We retrospectively analyzed data from 45 IMD and 230 BA recipients. We collected information on the occurrence and timing of episodes of CMV infections, methylprednisolone (mPSL) pulse therapy, patient characteristics, and peri- and postoperative data.

RESULTS

Multivariable analysis identified mPSL pulse therapy (Odds Ratio (OR): 4.43), CMV serostatus (D+/R-) (OR: 6.03), and underlying IMDs (OR: 3.28) as independent risk factors for CMV infection. Further stratified analysis, which considered the timing of CMV infection diagnosis relative to mPSL pulse therapy, confirmed that CMV serostatus with (D+/R-) (OR: 5.61) and underlying IMDs (OR: 2.83) remained independent predictors of CMV infection, even when excluding the influence of mPSL pulse therapy.

CONCLUSIONS

This study demonstrates that IMDs are a potent independent risk factor for CMV infection following pediatric liver transplantation.

CLINICAL TRIAL NUMBER

Not applicable.

Development and characterization of HCMV recombinant subunit vaccines based on T-cell epitopes

Human cytomegalovirus (HCMV), a ubiquitous β-herpes virus, mostly causes asymptomatic infections in adults with healthy immune systems. Due to immunosuppressive therapy, solid organ transplantation (SOT) recipients are at increased risk of HCMV infection. In recent years, the interdisciplinary, filed of immunoinformatics, based on computer science, and modern immunology, has emerged. In this study, we designed three types of recombinant subunit vaccines, which are expressed by the E. coli BL21 strain according to immunoinformatics prediction. Subsequently, we evaluated the innate and cellular immune responses of recombinant subunit vaccines in vivo and/or in vitro. Flow cytometry analysis, revealed that recombinant subunit vaccines enhanced both innate and cellular immune responses in vivo and/or in vitro. We also found that the novel herb adjuvant hesperetin (HES) increased memory T cell inflation. Overall, we developed three types of recombinant subunit vaccines based on HCMV antigen fragments containing multiple T-cell epitopes and assessed the innate and cellular immune responses in vivo and/or in vitro.

Memory inflation: Beyond the acute phase of viral infection

Memory inflation is confirmed as the most commonly dysregulation of host immunity with antigen-independent manner in mammals after viral infection. By generating large numbers of effector/memory and terminal differentiated effector memory CD8+ T cells with diminished naïve subsets, memory inflation is believed to play critical roles in connecting the viral infection and the onset of multiple diseases. Here, we reviewed the current understanding of memory inflated CD8+ T cells in their distinct phenotypic features that different from exhausted subsets; the intrinsic and extrinsic roles in regulating the formation of memory inflation; and the key proteins in maintaining the expansion and proliferation of inflationary populations. More importantly, based on the evidences from both clinic and animal models, we summarized the potential mechanisms of memory inflation to trigger autoimmune neuropathies, such as Guillain-Barré syndrome and multiple sclerosis; the correlations of memory inflation between tumorigenesis and resistance of tumour immunotherapies; as well as the effects of memory inflation to facilitate vascular disease progression. To sum up, better understanding of memory inflation could provide us an opportunity to beyond the acute phase of viral infection, and shed a light on the long-term influences of CD8+ T cell heterogeneity in dampen host immune homeostasis.

[Management of Cytomegalovirus Infection in Allogeneic Hematopoietic Stem Cell Transplant Recipients]

Cytomegalovirus (CMV) is a type of double-stranded deoxyribonucleic acid virus belonging to the herpesviridae family. Following a primary infection, the virus becomes latent in various types of white blood cells. Cytomegalovirus infection can remain latent or become active, especially in immunocompromised individuals, such as those undergoing hematopoietic stem cell transplantation (HSCT), where CMV reactivation can occur. In this context, CMV infection is common and associated with high rates of morbidity and mortality. Pneumonia is one of the most serious complications, with mortality rates exceeding 50%. Additionally, even in the absence of organ-specific disease, CMV infection is related to increased mortality unrelated to hematologic neoplasm recurrence. Given the frequency and severity of this infection in HSCT patients, it is crucial to implement effective strategies for monitoring, prevention, and treatment. This guideline was developed to identify patient groups that benefit from a systematic approach to CMV infection and to define the most appropriate strategy for each group. Monitoring CMV viral load in peripheral blood is crucial, especially in patients at moderate to high risk of active infection. Primary prophylaxis with letermovir (an antiviral drug) is recommended to reduce the incidence of active infection, especially in high-risk patients. Secondary prophylaxis with valganciclovir (antiviral drug) is recommended after an episode of active infection, while preemptive and disease treatment is based on monitoring viral load and clinical response. The aim of this guideline is to improve the approach to CMV infection in HSCT patients, ensuring an effective and safe preventive and therapeutic approach.

Delivery of US28 by incoming HCMV particles rapidly attenuates Akt activity to suppress HCMV lytic replication in monocytes

Establishing a nonproductive, quiescent infection within monocytes is essential for the spread of human cytomegalovirus (HCMV). We investigated the mechanisms through which HCMV establishes a quiescent infection in monocytes. US28 is a virally encoded G protein-coupled receptor (GPCR) that is essential for silent infections within cells of the myeloid lineage. We found that preformed US28 was rapidly delivered to monocytes by HCMV viral particles, whereas the de novo synthesis of US28 was delayed for several days. A recombinant mutant virus lacking US28 (US28Δ) was unable to establish a quiescent infection, resulting in a fully productive lytic infection able to produce progeny virus. Infection with US28Δ HCMV resulted in the phosphorylation of the serine and threonine kinase Akt at Ser473 and Thr308, in contrast with the phosphorylation of Akt only at Ser473 after WT viral infection. Inhibiting the dual phosphorylation of Akt prevented the lytic replication of US28Δ, and ectopic expression of a constitutively phosphorylated Akt variant triggered lytic replication of wild-type HCMV. Mechanistically, we found that US28 was necessary and sufficient to attenuate epidermal growth factor receptor (EGFR) signaling induced during the entry of WT virus, which led to the site-specific phosphorylation of Akt at Ser473. Thus, particle-delivered US28 fine-tunes Akt activity by limiting HCMV-induced EGFR activation during viral entry, enabling quiescent infection in monocytes.

Cytomegalovirus gastritis as a rare adverse event during combined ipilimumab and nivolumab in a patient with melanoma

Immunotherapy has improved survival outcomes of patients with advanced melanoma. Lower gastrointestinal tract immune-related adverse events (irAEs) are common during treatment; however, gastritis is not frequently observed. Herein, we report a case of severe cytomegalovirus (CMV)-related gastritis in a patient treated with ipilimumab and nivolumab for metastatic melanoma. This report presents a 60-year-old woman with stage IV BRAF wild-type melanoma. After the second course of ipilimumab-nivolumab, the patient reported epigastric discomfort after meals, anorexia, and subsequent nausea, vomiting, epigastric pain, and weight loss. Disease staging with PET/CT scan showed very good partial response and diffuse gastroduodenitis. The patient underwent esophagogastroduodenoscopy, showing severe esophageal candidiasis and diffuse hemorrhagic, edematous, and ulcerative mucosa in the whole gastric wall. Biopsies of the gastric wall were obtained. Before receipt of the final pathology report, the patient was empirically started on corticosteroids based on the clinical suspicion of immune-related gastritis, without improvement of symptoms. The hematoxylin-eosin staining demonstrated active gastritis with diffuse nuclear cytopathic viral inclusions in epithelial and interstitial cells; CMV infection was confirmed with immunohistochemical staining. The patient started ganciclovir and fluconazole, with rapid improvement of symptoms. This case presents a rare instance of CMV gastritis in a patient receiving combined anti-PD1 and anti-CTLA4 , in the absence of immune-suppression to manage an irAE. In the case of suggestive symptoms of irAEs, a high index of clinical suspicion is required to rule out concomitant or isolated infective disease. Guidelines for prophylaxis and treatment of these patients are needed, to optimize treatment results.

Dynamic monitoring of viral gene expression reveals rapid antiviral effects of CD8 T cells recognizing the HCMV-pp65 antigen

Introduction

Human Cytomegalovirus (HCMV) is a betaherpesvirus that causes severe disease in immunocompromised transplant recipients. Immunotherapy with CD8 T cells specific for HCMV antigens presented on HLA class-I molecules is explored as strategy for long-term relief to such patients, but the antiviral effectiveness of T cell preparations cannot be efficiently predicted by available methods.

Methods

We developed an Assay for Rapid Measurement of Antiviral T-cell Activity (ARMATA) by real-time automated fluorescent microscopy and used it to study the ability of CD8 T cells to neutralize HCMV and control its spread. As a proof of principle, we used TCR-transgenic T cells specific for the immunodominant HLA-A02-restricted tegumental phosphoprotein pp65. pp65 expression follows an early/late kinetic, but it is not clear at which stage of the virus cycle it acts as an antigen. We measured control of HCMV infection by T cells as early as 6 hours post infection (hpi).

Results

The timing of the antigen recognition indicated that it occurred before the late phase of the virus cycle, but also that virion-associated pp65 was not recognized during virus entry into cells. Monitoring of pp65 gene expression dynamics by reporter fluorescent genes revealed that pp65 was detectable as early as 6 hpi, and that a second and much larger bout of expression occurs in the late phase of the virus cycle by 48 hpi. Since transgenic (Tg)-pp65 specific CD8 T cells were activated even when DNA replication was blocked, our data argue that pp65 acts as an early virus gene for immunological purposes.

Discussion

ARMATA does not only allow same day identification of antiviral T-cell activity, but also provides a method to define the timing of antigen recognition in the context of HCMV infection.

Cellular immunity against cytomegalovirus and risk of infection after kidney transplantation

Introduction

Cytomegalovirus (CMV) infection remains a challenge following kidney transplantation (KTx). Currently, CMV-IgG serostatus at transplantation is used to individualize CMV preventive strategies. We assessed the clinical utility of CMV-IGRA for predicting CMV infection following KTx.

Methods

We performed a nationwide prospective cohort study from August 2016 until December 2022. Data from all adult KTx recipients in Norway, n=1,546 (R+; n=1,157, D+/R-; n=260, D-/R-; 129), were included with a total of 3,556 CMV-IGRA analyses (1,375 at KTx, 1,188 at eight weeks, 993 one-year after KTx) and 35,782 CMV DNAemia analyses.

Results

In R+ recipients CMV-IGRA status, measured at any of the time-points, could not identify any differential risk of later CMV infection. D+/R- recipients remaining CMV-IGRA negative 1-year after transplantation (regardless of positive CMV DNAemia and/or CMV IgG status at that time) had increased risk of developing later CMV infection compared to D+/R- recipients who had become CMV-IGRA positive (14% vs. 2%, p=0.01).

Conclusion

Knowledge of pre-transplant CMV-IGRA status did not provide additional information to CMV-IgG serostatus that could improve current post-transplant CMV treatment algorithms. However, D+/R- recipients with a persisting negative CMV-IGRA one-year after transplantation remained at increased risk of experiencing later CMV infection. Therefore we advocate post-transplant CMV-IGRA monitoring in these patients.

Human cytomegalovirus seropositivity and its influence on oral rotavirus vaccine immunogenicity: a specific concern for HIV-exposed-uninfected infants

Oral rotavirus vaccines demonstrate diminished immunogenicity in low-income settings where human cytomegalovirus infection is acquired early in childhood and modulates immunity. We hypothesized that human cytomegalovirus infection around the time of vaccination may influence immunogenicity. We measured plasma human cytomegalovirus-specific immunoglobulin M antibodies in rotavirus vaccinated infants from 6 weeks to 12 months old and compared rotavirus immunoglobulin A antibody titers between human cytomegalovirus seropositive and seronegative infants. There was no evidence of an association between human cytomegalovirus serostatus at 9 months and rotavirus-specific antibody titers at 12 months (geometric mean ratio 1.01, 95% CI: 0.70, 1.45; P = 0.976) or fold-increase in RV-IgA titer between 9 and 12 months (risk ratio 0.999, 95%CI: 0.66, 1.52; P = 0.995) overall. However, HIV-exposed-uninfected infants who were seropositive for human cytomegalovirus at 9 months old had a 63% reduction in rotavirus antibody geometric mean titers at 12 months compared to HIV-exposed-uninfected infants who were seronegative for human cytomegalovirus (geometric mean ratio 0.37, 95% CI: 0.17, 0.77; P = 0.008). While the broader implications of human cytomegalovirus infections on oral rotavirus vaccine response might be limited in the general infant population, the potential impact in the HIV-exposed-uninfected infants cannot be overlooked. This study highlights the complexity of immunological responses and the need for targeted interventions to ensure oral rotavirus vaccine efficacy, especially in vulnerable subpopulations.

Engineered HCMV-infected APCs enable the identification of new immunodominant HLA-restricted epitopes of anti-HCMV T-cell immunity

Complications due to HCMV infection or reactivation remain a challenging clinical problem in immunocompromised patients, mainly due to insufficient or absent T-cell functionality. Knowledge of viral targets is crucial to improve monitoring of high-risk patients and optimise antiviral T-cell therapy. To expand the epitope spectrum, genetically-engineered dendritic cells (DCs) and fibroblasts were designed to secrete soluble (s)HLA-A*11:01 and infected with an HCMV mutant lacking immune evasion molecules (US2-6 + 11). More than 700 HLA-A*11:01-restricted epitopes, including more than 50 epitopes derived from a broad range of HCMV open-reading-frames (ORFs) were identified by mass spectrometry and screened for HLA-A*11:01-binding using established prediction tools. The immunogenicity of the 24 highest scoring new candidates was evaluated in vitro in healthy HLA-A*11:01+/HCMV+ donors. Thus, four subdominant epitopes and one immunodominant epitope, derived from the anti-apoptotic protein UL36 and ORFL101C (A11SAL), were identified. Their HLA-A*11:01 complex stability was verified in vitro. In depth analyses revealed highly proliferative and cytotoxic memory T-cell responses against A11SAL, with T-cell responses comparable to the immunodominant HLA-A*02:01-restricted HCMVpp65NLV epitope. A11SAL-specific T cells were also detectable in vivo in immunosuppressed transplant patients and shown to be effective in an in vitro HCMV-infection model, suggesting their crucial role in inhibiting viral replication and improvement of patient's outcome. The developed in vitro pipeline is the first to utilise genetically-engineered DCs to identify naturally presented immunodominant HCMV-derived epitopes. It therefore offers advantages over in silico predictions, is transferable to other HLA alleles, and will significantly expand the repertoire of viral targets to improve therapeutic options.

Association between cytomegalovirus viremia and long-term outcomes in lung transplant recipients

Although cytomegalovirus (CMV) viremia/DNAemia has been associated with reduced survival after lung transplantation, its association with chronic lung allograft dysfunction (CLAD) and its phenotypes is unclear. We hypothesized that, in a modern era of CMV prophylaxis, CMV DNAemia would still remain associated with death, but also represent a risk factor for CLAD and specifically restrictive allograft syndrome (RAS)/mixed phenotype. This was a single-center retrospective cohort study of all consecutive adult, first, bilateral-/single-lung transplants done between 2010-2016, consisting of 668 patients. Risks for death/retransplantation, CLAD, or RAS/mixed, were assessed by adjusted cause-specific Cox proportional-hazards models. CMV viral load (VL) was primarily modeled as a categorical variable: undetectable, detectable to 999, 1000 to 9999, and ≥10 000 IU/mL. In multivariable models, CMV VL was significantly associated with death/retransplantation (≥10 000 IU/mL: HR = 2.65 [1.78-3.94]; P < .01), but was not associated with CLAD, whereas CMV serostatus mismatch was (D+R-: HR = 2.04 [1.30-3.21]; P < .01). CMV VL was not associated with RAS/mixed in univariable analysis. Secondary analyses with a 7-level categorical or 4-level ordinal CMV VL confirmed similar results. In conclusion, CMV DNAemia is a significant risk factor for death/retransplantation, but not for CLAD or RAS/mixed. CMV serostatus mismatch may have an impact on CLAD through a pathway independent of DNAemia.

cGAS-STING-TBK1 Signaling Promotes Valproic Acid-Responsive Human Cytomegalovirus Immediate-Early Transcription during Infection of Incompletely Differentiated Myeloid Cells

Repression of human cytomegalovirus (HCMV) immediate-early (IE) gene expression is a key regulatory step in the establishment and maintenance of latent reservoirs. Viral IE transcription and protein accumulation can be elevated during latency by treatment with histone deacetylase inhibitors such as valproic acid (VPA), rendering infected cells visible to adaptive immune responses. However, the latency-associated viral protein UL138 inhibits the ability of VPA to enhance IE gene expression during infection of incompletely differentiated myeloid cells that support latency. UL138 also limits the accumulation of IFNβ transcripts by inhibiting the cGAS-STING-TBK1 DNA-sensing pathway. Here, we show that, in the absence of UL138, the cGAS-STING-TBK1 pathway promotes both IFNβ accumulation and VPA-responsive IE gene expression in incompletely differentiated myeloid cells. Inactivation of this pathway by either genetic or pharmacological inhibition phenocopied UL138 expression and reduced VPA-responsive IE transcript and protein accumulation. This work reveals a link between cytoplasmic pathogen sensing and epigenetic control of viral lytic phase transcription and suggests that manipulation of pattern recognition receptor signaling pathways could aid in the refinement of MIEP regulatory strategies to target latent viral reservoirs.

Cytomegalovirus Infection in Adult Patients with Inflammatory Bowel Disease: A Literature Review

Human cytomegalovirus (HCMV) is classified within the Herpesvirales order and is prevalent in 50%‒80% of the general population. Most carriers experience this infection without noticeable clinical symptoms. HCMV causes a lifelong latent infection that can be reactivated due to immune disorders and inflammation. The reactivation of HCMV becomes particularly significant when it coincides with inflammatory bowel disease (IBD). While cytomegalovirus (CMV) colitis in IBD patients was identified years ago, the role of CMV in triggering flare-ups, acute severe colitis, treatment resistance, and other outcomes in IBD patients experiencing CMV reactivation remains a subject of ongoing debate. In this review, we aim to address an updated insight into aspects related to the CMV colitis in IBD patients including epidemiology, risk factors, clinical features, diagnostic tests, histology, place of immunosuppressants and indications for antiviral treatment. We suggest for personalized and thorough assessment based on the disease phase and colitis severity when prescribing drugs to these patients. Furthermore, we emphasize the importance of regular patient follow-up to monitor drug side effects, ensuring treatment success, and minimizing the risk of colectomy.

Cytomegalovirus Cell-mediated Immunity Assays in Pediatric Transplantation

Cytomegalovirus (CMV) is a significant cause of morbidity and mortality in pediatric transplantation. However, currently utilized CMV prevention paradigms have limitations, leading to research aimed at novel strategies for mitigation of CMV infection. Cell-mediated immunity (CMI) is crucial in controlling CMV infection and the use of CMV-specific CMI assays to guide prevention and treatment of CMV infection in both solid organ transplant and hematopoietic cell transplant recipients shows great promise. In this article, we review the immune response to CMV infection to highlight the rationale for CMI assays, describe available commercial assays and strategies for their use, and summarize relevant literature regarding the use of CMI assays in transplant recipients.

Diverse cytomegalovirus US11 antagonism and MHC-A evasion strategies reveal a tit-for-tat coevolutionary arms race in hominids

Recurrent, ancient arms races between viruses and hosts have shaped both host immunological defense strategies as well as viral countermeasures. One such battle is waged by the glycoprotein US11 encoded by the persisting human cytomegalovirus. US11 mediates degradation of major histocompatibility class I (MHC-I) molecules to prevent CD8+ T-cell activation. Here, we studied the consequences of the arms race between US11 and primate MHC-A proteins, leading us to uncover a tit-for-tat coevolution and its impact on MHC-A diversification. We found that US11 spurred MHC-A adaptation to evade viral antagonism: In an ancestor of great apes, the MHC-A A2 lineage acquired a Pro184Ala mutation, which confers resistance against the ancestral US11 targeting strategy. In response, US11 deployed a unique low-complexity region (LCR), which exploits the MHC-I peptide loading complex to target the MHC-A2 peptide-binding groove. In addition, the global spread of the human HLA-A*02 allelic family prompted US11 to employ a superior LCR strategy with an optimally fitting peptide mimetic that specifically antagonizes HLA-A*02. Thus, despite cytomegaloviruses low pathogenic potential, the increasing commitment of US11 to MHC-A has significantly promoted diversification of MHC-A in hominids.

Identification of novel canonical and cryptic HCMV-specific T-cell epitopes for HLA-A∗03 and HLA-B∗15 via peptide-PRISM

ABSTRACT

Human cytomegalovirus (HCMV) reactivation poses a substantial risk to patients receiving tranplants. Effective risk stratification and vaccine development is hampered by a lack of HCMV-derived immunogenic peptides in patients with common HLA-A∗03:01 and HLA-B∗15:01 haplotypes. This study aimed to discover novel HCMV immunogenic peptides for these haplotypes by combining ribosome sequencing (Ribo-seq) and mass spectrometry with state-of-the-art computational tools, Peptide-PRISM and Probabilistic Inference of Codon Activities by an EM Algorithm. Furthermore, using machine learning, an algorithm was developed to predict immunogenicity based on translational activity, binding affinity, and peptide localization within small open reading frames to identify the most promising peptides for in vitro validation. Immunogenicity of these peptides was subsequently tested by analyzing peptide-specific T-cell responses of HCMV-seropositive and -seronegative healthy donors as well as patients with transplants. This resulted in the direct identification of 3 canonical and 1 cryptic HLA-A∗03-restricted immunogenic peptides as well as 5 canonical and 1 cryptic HLA-B∗15-restricted immunogenic peptide, with a specific interferon gamma-positive (IFN-γ+)/CD8+ T-cell response of ≥0.02%. High T-cell responses were detected against 2 HLA-A∗03-restricted and 3 HLA-B∗15-restricted canonical peptides with frequencies of up to 8.77% IFN-γ+/CD8+ T cells in patients after allogeneic stem cell transplantation. Therefore, our comprehensive strategy establishes a framework for efficient identification of novel immunogenic peptides from both existing and novel Ribo-seq data sets.

Using a commercially available assay that measures cytomegalovirus (CMV)-specific T-cell immunity to predict protection against CMV: A prospective, blinded clinical study

The Viracor CMV-T-cell immunity Panel (TCIP) measures %CMV-specific CD4+ and CD8+ T-cells. In this blinded clinical study, we evaluated the performance of the TCIP in predicting CMV events. Prospectively enrolled donor or recipient CMV-seropositive kidney transplant recipients (KTR) were evaluated with monthly TCIP testing until either discontinuation of valganciclovir prophylaxis or CMV DNAemia prompting treatment initiation. Also, prospectively enrolled KTR with low-level untreated DNAemia or after completion of treatment were evaluated for progression or relapse of CMV infection. Among 46 KTR, those with CMV events had significantly lower %CMV-specific CD8+ T-cells (p = 0.024), and the CMV protection ROC AUC was significant (AUC 0.78, p = 0.026). The positive predictive values of CD4+ and CD8+ T-cell positivity >0.2 % for CMV protection were: 96.3 % for CMV DNAemia prompting treatment initiation, 92.6 % for any DNAemia, 100 % for DNAemia >1000 IU/mL. The TCIP could be a useful adjunct tool in individualized management of CMV infection.

Cytomegalovirus Infection in Patient with Clear Cell Renal Cell Carcinoma

Introduction

Cytomegalovirus (CMV) infection is a widespread condition that can affect individuals of all ages. Most cases of CMV infection are mild and resolve on their own. However, in immunocompromised individuals, such as post-transplant patients or those with cancer, severe infections can occur. While there have been several studies on CMV infection in post-transplant patients, there is limited literature on CMV infection in cancer, particularly in kidney cancer. Case Report. In this case report, we present the case of a 61-year-old man with clear cell renal cell carcinoma who underwent targeted therapy with the receptor tyrosine kinase (RTK) inhibitor lenvatinib and the mammalian target of rapamycin (mTOR) inhibitor everolimus. The patient was hospitalized for 26 days and admitted to the intensive care unit (ICU) due to shortness of breath, decreased oxygen saturation, and irregular breathing. Cytomegalovirus polymerase chain reaction (PCR) test results were positive. Given the high prevalence of CMV infection in developing countries, it is likely that the patient had a reactivation of CMV. As such, the patient was subsequently treated with ganciclovir for 14 days and showed improvement in symptoms such as shortness of breath, cough, fever, and increased oxygen saturation. Following recovery, the patient received maintenance therapy with oral valganciclovir for 7 days. No further symptoms appeared during subsequent cancer treatments.

Conclusion

Cancer patients who are undergoing treatment are at a higher risk for developing opportunistic infections, which can result in morbidity and mortality. Therefore, healthcare professionals should be aware of the possibility of CMV infection in cancer patients and be prepared to diagnose and treat the infection, particularly in areas where the prevalence of CMV infection is high.

QuantiFERON-CMV and monitor predict cytomegalovirus, mortality, and graft-versus-host disease in transplant recipients

Cytomegalovirus (CMV) is the most prevalent infection in recipients of hematopoietic stem cell transplant (HSCT). QuantiFERON-CMV (QF-CMV) and QuantiFERON-Monitor (QFM) assays were used to test whether immune-competent adult allogeneic HSCT recipients with CMV-specific T cells can control CMV infection or reactivation. Our data demonstrated a significant correlation between CMV infection measured by CMV-antigenemia test and QF-CMV results, graft versus host disease (GvHD), and mortality rates. The QF-CMV test revealed that CMV-specific T cells with higher interferon-γ (IFN-γ) release were correlated with lower CMV infection rates. There was a significant negative association between QF-CMV results, GvHD, and mortality rates. Data showed that a one-unit rise in IFN-γ was linked with a 12.7% reduction in GvHD and a 20.7% reduction in the mortality odds ratio. In addition, a negative correlation was found between QF-M results and CMV infection, with the QFM test predicting protection against CMV infection by 1.9%. This is one of the few studies establishing the QF-CMV test's predictive value for GvHD and mortality, its use to monitor HSCT patients for pre-emptive therapy, and the use of the QFM test to predict CMV infection and mortality in HSCT patients. Thus, these assays could be utilized to optimize preventive and pre-emptive therapy procedures to reduce transplant recipient adverse effects and posttransplant therapy costs.

Alzheimer's disease as a viral disease: Revisiting the infectious hypothesis

Alzheimer's disease (AD) represents the most frequent type of dementia in elderly people. Two major forms of the disease exist: sporadic - the causes of which have not yet been fully understood - and familial - inherited within families from generation to generation, with a clear autosomal dominant transmission of mutations in Presenilin 1 (PSEN1), 2 (PSEN2) or Amyloid Precursors Protein (APP) genes. The main hallmark of AD consists of extracellular deposits of amyloid-beta (Aβ) peptide and intracellular deposits of the hyperphosphorylated form of the tau protein. An ever-growing body of research supports the viral infectious hypothesis of sporadic forms of AD. In particular, it has been shown that several herpes viruses (i.e., HHV-1, HHV-2, HHV-3 or varicella zoster virus, HHV-4 or Epstein Barr virus, HHV-5 or cytomegalovirus, HHV-6A and B, HHV-7), flaviviruses (i.e., Zika virus, Dengue fever virus, Japanese encephalitis virus) as well as Human Immunodeficiency Virus (HIV), hepatitis viruses (HAV, HBV, HCV, HDV, HEV), SARS-CoV2, Ljungan virus (LV), Influenza A virus and Borna disease virus, could increase the risk of AD. Here, we summarized and discussed these results. Based on these findings, significant issues for future studies are also put forward.

Cardinal features of immune memory in innate lymphocytes

The ability of vertebrates to 'remember' previous infections had once been attributed exclusively to adaptive immunity. We now appreciate that innate lymphocytes also possess memory properties akin to those of adaptive immune cells. In this Review, we draw parallels from T cell biology to explore the key features of immune memory in innate lymphocytes, including quantity, quality, and location. We discuss the signals that trigger clonal or clonal-like expansion in innate lymphocytes, and highlight recent studies that shed light on the complex cellular and molecular crosstalk between metabolism, epigenetics, and transcription responsible for differentiating innate lymphocyte responses towards a memory fate. Additionally, we explore emerging evidence that activated innate lymphocytes relocate and establish themselves in specific peripheral tissues during infection, which may facilitate an accelerated response program akin to those of tissue-resident memory T cells.

Establishment and application of a point-of-care testing and diagnosis method for early immediate expression gene IE1 of cytomegalovirus in maternal urine based on isothermal amplification

BACKGROUND

Human Cytomegalovirus virus (HCMV) is a worldwide virus that causes no serious symptoms in most adults. However, HCMV infection during pregnancy, it may lead to a series of serious complications, such as hearing loss, mental retardation, visual impairment, microcephaly and developmental retardation.

AIM

The aim of this study was to develop a simple, low dependence on equipment and accurate method for HCMV detection based on the recombinase polymerase amplification (RPA) and lateral flow chromatography strip (LFS) reading.

METHODS

In order to meet the feasibility of HCMV early screening, three pairs of RPA primers were designed based on the UL123 gene encoding IE1, which was expressed immediately in the early stage of HCMV. In order to improve the specificity of the reaction and satisfy the visual detection, a specific probe was designed to insert THF site between upstream and downstream primers, fluorescein isothiocyanate (FITC) and C3spacer were used to modify the 5' end and the 3' end respectively, and Biotin was used to modify the 5' end of the reverse primer. HCMV standard strain AD169 was enriched by ARPE-19 cells culture, and its genome was extracted. The primers and probes were screened by RPA-LFS test, and the optimal reaction temperature and time were determined The specificity was verified in different viruses, bacteria and parasites. The standard curve was drawn based on the constructed recombinant plasmid of pMD18T-HCMV-UL123 and used for HCMV genomic DNA quantification and determination of the detection sensitivity. Urine samples from artificial HCMV contamination or clinical collection were prepared to evaluate the consistency with the results of real-time quantitative PCR.

RESULTS

The results showed that the primers and probes for HCMV RPA-LFS detection based on UL123 gene were successfully screened, the amplification of HCMV genomic DNA with as low as 30 copies could be completed at 37 °C within 15 min, it did not react with Human herpesvirus 1, Streptococcus pyogenes, Candida albicans, Listeria monocytogenes, Y. enterocolitica, Klebsiella Pneumoniae, Enterobacter cloacae, Citrobacter freundii, Vibrio alginnolyfificus, Vibrio parahaemolyticus, S. typhimurium, Staphylococcus aureus, Pseudomonas aeruginosa and Trichomonas vaginalis. The positive rate of PCR was 96.67 % in 30 simulated urine samples and 100 % in 127 clinical urine samples with the same UL123 gene detection.

CONCLUSIONS

To sum up, we developed a diagnostic method for HCMV based on UL123 gene combined with RPA and LFS, which is low dependent on equipment, fast, sensitive and specific, provide reference for point-of-care testing HCMV in grass-roots laboratories and remote areas.

Ocular Inflammation Post-Vaccination

The association between vaccines and ocular disorders has attracted significant attention in scientific research. Numerous mainstream vaccines are associated with a range of uveitis types, including anterior, intermediate, and posterior uveitis. Additionally, they are associated with distinct ocular diseases such as multifocal choroiditis, Vogt-Koyanagi-Harada (VKH) disease, acute posterior multifocal placoid pigment epitheliopathy (APMPPE), and multiple evanescent white dot syndrome (MEWDS). These ocular conditions are often transient, with a vast majority of patients experiencing improvement after steroid intervention. To date, numerous cases of vaccine-induced uveitis have been reported. This study analyzed the correlation between antiviral vaccines, including the hepatitis B virus (HBV), human papillomavirus (HPV), measles-mumps-rubella (MMR), varicella zoster virus (VZV), and influenza vaccines, and different manifestations of uveitis. This is the first comprehensive study to offer a detailed analysis of uveitis types induced by antiviral vaccines. Through an extensive database search, we found a particularly strong link between influenza vaccines, followed by VZV and HPV vaccines. While anterior uveitis is common, conditions such as APMPPE, MEWDS, and VKH are particularly notable and merit careful consideration in clinical practice. Corticosteroid treatment was effective; however, half of the observed patients did not achieve full recovery, indicating potentially prolonged effects of the vaccine.

Human cytomegalovirus UL36 inhibits IRF3-dependent immune signaling to counterbalance its immunoenhancement as apoptotic inhibitor

Apoptotic inhibition and immune evasion have particular importance to efficient viral infection, while a dilemma often faced by viruses is that inhibiting apoptosis can up-regulate antiviral immune signaling. Herein, we uncovered that in addition to inhibiting caspase-8/extrinsic apoptosis, human cytomegalovirus (HCMV)-encoded UL36 suppresses interferon regulatory factor 3 (IRF3)-dependent immune signaling by directly targeting IRF3 to abrogate IRF3 interaction with stimulator of interferon genes or TANK-binding kinase 1 and inhibit IRF3 phosphorylation/activation. Although UL36-mediated caspase-8/extrinsic apoptosis inhibition enhances immune signaling, the immunosuppressing activity of UL36 counterbalances this immunoenhancing "side effect" undesirable for virus. Furthermore, we used mutational analyses to show that only the wild-type, but not the UL36 mutant losing either inhibitory activity, is sufficient to support effective HCMV replication in cells, showing the functional importance of the dual inhibition by UL36 for the HCMV life cycle. Together, our findings demonstrate a sophisticated mechanism by which HCMV tightly controls innate immune signaling and extrinsic apoptosis for efficient infection.

Clinical Features and Outcomes of Cytomegalovirus Retinitis in Immunosuppressed Non-HIV Patients

PURPOSE

To describe the nature and response of cytomegalovirus (CMV) retinitis in human immunodeficiency virus (HIV)-negative patients with hematological malignancies and other immunosuppressive causes.

METHODS

This is retrospective case series of CMV retinitis patients with known immunocompromised status and negative HIV results. Patients' data were reviewed for demographics, causes of the immunosuppressed status, concomitant systemic CMV infection, and its management. Ophthalmic findings included visual acuity (VA), anterior and posterior segments findings, CMV retinitis patterns and extensions, medications, number of intravitreal injections, fundus photographs, and CMV retinitis complications.

RESULTS

During a study period of 2 years, 17 eyes of 9 patients were diagnosed with CMV retinitis with detected CMV in blood tests. Indolent granular retinitis pattern was found in 4 eyes (23.5%), and the fulminant necrotizing pattern in another 4 eyes (23.5%). In 1 eye (5.9%), frosted branch angiitis was observed. A mixed pattern between granular and necrotizing retinitis was seen in 4 eye (23.5%). The majority (n 11, 64.7%) of the affected eyes had an extensive retinal involvement (zone 1-3). Only two eyes had no macular involvement (11.8%). A large percentage of the included patients had controlled disease course with stable vision. Out of the studied 17 eyes, deterioration in terms of VA was seen in five eyes. In two patients, the disease course was complicated by vitreous hemorrhage.

CONCLUSION

In the majority of the patients with HIV-negative tests who received intravitreal and/or systemic anti-CMV medications, the clinical course of CMV retinitis was controlled with final stable vision.

The Unmasking of Cytomegalovirus as an Accomplice to Helicobacter pylori-Induced Severe Acute Gastroenteritis in a Healthy Host

Cytomegalovirus (CMV) belongs to the Herpesviridae family, and it is considered the largest virus to infect humans. Primary CMV infection frequently targets immunodeficient patients and is often symptomatic. However, it may remain latent or clinically unapparent for years in immunocompetent individuals. CMV infection rarely presents as an invasive disease in the latter group of individuals, in which case, the most common site of involvement in the gastrointestinal tract. When CMV affects the gastrointestinal tract, the colon and stomach are the 2 frequently involved sites. This case report describes a unique case of an immunocompetent patient who presented with acute excruciating periumbilical pain and was diagnosed with acute gastritis secondary to CMV infection and possible Helicobacter pylori-associated chronic active gastritis. Symptoms resolved entirely soon after treatment with antimicrobials that cover for both infections. The diagnosis was based on histopathologic findings from biopsies taken from the stomach during the endoscopic evaluation combined with positive CMV serology and positive CMV-deoxyribonucleic acid.

Antiviral Approach to Cytomegalovirus Infection: An Overview of Conventional and Novel Strategies

Human cytomegalovirus (HCMV) is a herpesvirus capable of establishing a lifelong persistence in the host through a chronic state of infection and remains an essential global concern due to its distinct life cycle, mutations, and latency. It represents a life-threatening pathogen for immunocompromised patients, such as solid organ transplanted patients, HIV-positive individuals, and hematopoietic stem cell recipients. Multiple antiviral approaches are currently available and administered in order to prevent or manage viral infections in the early stages. However, limitations due to side effects and the onset of antidrug resistance are a hurdle to their efficacy, especially for long-term therapies. Novel antiviral molecules, together with innovative approaches (e.g., genetic editing and RNA interference) are currently in study, with promising results performed in vitro and in vivo. Since HCMV is a virus able to establish latent infection, with a consequential risk of reactivation, infection management could benefit from preventive treatment for critical patients, such as immunocompromised individuals and seronegative pregnant women. This review will provide an overview of conventional antiviral clinical approaches and their mechanisms of action. Additionally, an overview of proposed and developing new molecules is provided, including nucleic-acid-based therapies and immune-mediated approaches.

Virion-associated US28 rapidly modulates Akt activity to suppress HCMV lytic replication in monocytes

Establishing a non-productive quiescent/silent infection within monocytes is essential for spread of human cytomegalovirus (HCMV). Yet, how HCMV establishes a quiescent infection in monocytes remains unclear. US28 is a viral G protein-coupled receptor (GPCR) essential for silent infections within cells of the myeloid lineage. We found virion-associated US28 was rapidly delivered to monocytes, while de novo synthesized US28 was delayed for several days. A recombinant mutant virus lacking US28 (US28Δ) was unable to establish a quiescent infection, resulting in a fully productive lytic replication cycle. Mechanistically, viral entry of US28Δ phosphorylated Akt at both serine 473 (S473) and threonine 308 (T308), which contrasted with the site-specific phosphorylation of Akt at S473 following WT infection. Preventing Akt bi-phosphorylation prevented lytic replication of US28Δ, and ectopic expression of a constitutively phosphorylated Akt variant triggered lytic replication of WT infection. Our data demonstrate that virion-delivered US28 fine-tunes Akt activity to permit HCMV infection to enter a quiescent state following primary infection of monocytes.

Continuous multi-membrane chromatography of large viral particles

Continuous multi-column chromatography (CMCC) has been successfully implemented to address biopharmaceutical biomolecule instability, to improve process efficiency, and to reduce facility footprint and capital cost. This paper explores the implementation of a continuous multi-membrane chromatography (CMMC) process, using four membrane units, for a large viral particle in just few weeks. CMMC improves the efficiency of the chromatography step by enabling higher loads with smaller membranes for multiple cycles of column use and enables steady-state continuous bioprocessing. The separation performance of CMMC was compared to a conventional batch chromatographic capture step used at full manufacturing scale. The product step yield was 80% using CMMC versus 65% in batch mode while increasing slightly the relative purity. Furthermore, the total amount of membrane area required for the CMMC approach was approximately 10% of the area needed for batch operation, while realizing similar processing times. Since CMMC uses smaller membrane sizes, it can take advantage of the high flow rates achievable for membrane chromatography that are not typically possible at larger membrane scales due to skid flow rate limitations. As such, CMMC offers the potential for more efficient and cost-effective purification trains.

CMV hyperimmune globulin as salvage therapy for recurrent or refractory CMV infection in children undergoing hematopoietic stem cell transplantation

Cytomegalovirus (CMV) is a major cause of allogeneic hematopoietic stem cell transplant (HSCT)-related morbidity and mortality. Treatment failure continues to be a major issue in patients with CMV infection due to both drug resistance and intolerance. This single-center brief retrospective analysis of a case series aims to investigate the safety and efficacy of CMV-hyperimmune globulin as salvage therapy for CMV infection in children undergoing HSCT. Fifteen pediatric patients received human CMV-specific immunoglobulin (CMVIG) between July 2018 and December 2021 as a salvage therapy for refractory or recurrent CMV infection. At the time of CMVIG prescription, eight children presented with recurrent CMV infection and seven with refractory CMV infection. The overall response rate was 67% at 50 days from the CMVIG administration [95% confidence interval (CI): 44-88]. Overall survival (OS) from CMVIG administration at 100 days was 87% (95% CI: 56-96), and OS from HSCT at 1 year was 80% (95% CI: 50-93). Four patients died, three unrelated to CMV infection and one due to CMV pneumonia. CMVIG as salvage therapy was well tolerated, and no infusion-related adverse events were observed.

Immune-checkpoint expression in antigen-presenting cells (APCs) of cytomegaloviruses infection after transplantation: as a diagnostic biomarker

Cytomegalovirus (CMV), a member of the Herpesviridae family, mostly causes only slight feverish symptoms or can be asymptomatic in immunocompetent individuals. However, it is known to be particularly a significant cause of morbidity in immunocompromised patients, including transplant recipients, whose immune system has been weakened due to the consumption of immunosuppressor drugs. Therefore, the diagnosis of CMV infection after transplantation is crucial. New diagnostic methods for the quick detection of CMV have been developed as a result of understanding the clinical importance of invasive CMV. Antigen-presenting cells (APCs) and T cells are important components of the immune system and it may be possible to diagnose viral infections using immunological markers, such as lymphocytosis, cytotoxic T lymphocytes (CTL), and serum cytokine levels. Moreover, PD-1, CTLA 4, and TIGIT, which are expressed on certain T cells and antigen-presenting cells, are over-expressed during the infection. The assessment of CMV infection based on T cell and APC activity, and the expression of immunological checkpoints, can be helpful for the diagnosis of transplant patients at risk for CMV infection. In this review, we will investigate how immune checkpoints affect immune cells and how they impair organ transplantation after CMV infection.

A Cysteine Residue of Human Cytomegalovirus vMIA Protein Plays a Crucial Role in Viperin Trafficking to Control Viral Infectivity

Viperin is a multifunctional interferon-inducible protein that is directly induced in cells by human cytomegalovirus (HCMV) infection. The viral mitochondrion-localized inhibitor of apoptosis (vMIA) interacts with viperin at the early stages of infection and translocates it from the endoplasmic reticulum to the mitochondria, where viperin modulates the cellular metabolism to increase viral infectivity. Viperin finally relocalizes to the viral assembly compartment (AC) at late stages of infection. Despite the importance of vMIA interactions with viperin during viral infection, their interacting residues are unknown. In the present study, we showed that cysteine residue 44 (Cys44) of vMIA and the N-terminal domain (amino acids [aa] 1 to 42) of viperin are necessary for their interaction and for the mitochondrial localization of viperin. In addition, the N-terminal domain of mouse viperin, which is structurally similar to that of human viperin, interacted with vMIA. This indicates that the structure, rather than the sequence composition, of the N-terminal domain of viperin, is required for the interaction with vMIA. Recombinant HCMV, in which Cys44 of vMIA was replaced by an alanine residue, failed to translocate viperin to the mitochondria at the early stages of infection and inefficiently relocalized it to the AC at late stages of infection, resulting in the impairment of viperin-mediated lipid synthesis and a reduction in viral replication. These data indicate that Cys44 of vMIA is therefore essential for the intracellular trafficking and function of viperin to increase viral replication. Our findings also suggest that the interacting residues of these two proteins are potential therapeutic targets for HCMV-associated diseases. IMPORTANCE Viperin traffics to the endoplasmic reticulum (ER), mitochondria, and viral assembly compartment (AC) during human cytomegalovirus (HCMV) infection. Viperin has antiviral activity at the ER and regulates cellular metabolism at the mitochondria. Here, we show that Cys44 of HCMV vMIA protein and the N-terminal domain (aa 1 to 42) of viperin are necessary for their interaction. Cys44 of vMIA also has a critical role for viperin trafficking from the ER to the AC via the mitochondria during viral infection. Recombinant HCMV expressing a mutant vMIA Cys44 has impaired lipid synthesis and viral infectivity, which are attributed to mislocalization of viperin. Cys44 of vMIA is essential for the trafficking and function of viperin and may be a therapeutic target for HCMV-associated diseases.

Torque teno virus viremia and QuantiFERON®-CMV assay in prediction of cytomegalovirus reactivation in R+ kidney transplant recipients

Introduction

Cytomegalovirus (CMV) is the most frequent infectious complication following solid organ transplantation. Torque teno viruses (TTV) viremia has been proposed as a biomarker of functional immunity in the management of kidney transplant recipients (KTR). The QuantiFERON^®-CMV (QF-CMV) is a commercially available assay that allows the assessment of CD8⁺ T-cell responses in routine diagnostic laboratories.

Methods

In a prospective national multicenter cohort of 64 CMV-seropositive (R+) KTR, we analyzed the value of TTV load and the two markers of the QF-CMV assay [QF-Ag (CMV-specific T-cell responses) and QF-Mg (overall T-cell responses)], alone and in combination, in prediction of CMV reactivation (≥3 log₁₀ IU/ ml) in the first post-transplant year. We compared previously published cut-offs and specific cut-offs optimized from ROC curves for our population.

Results

Using the conventional cut-off (3.45 log₁₀ copies/ml), TTV load at D0 [inclusion visit on the day of transplantation before induction (D0)], or at M1 (1-month post-transplant visit) perform better in predicting CMV viremia control than CMV reactivation. Survival analyses suggest a better performance of our optimized TTV cut-offs (3.78 log₁₀ copies/ml at D0 and 4.23 log₁₀ copies/ml at M1) for risk stratification of CMV reactivation in our R+ KTR cohort. The QF-CMV (QF-Ag = 0.2 IU/ml, and QF-Mg = 0.5 IU/ml) also appears to better predict CMV viremia control than CMV reactivation. Moreover, survival analyses suggest that the QF-Mg would perform better than the QF-Ag in stratifying the risk of CMV reactivation. The use of our optimized QF-Mg cut-off (1.27 IU/ml) at M1 further improved risk stratification of CMV reactivation. Using conventional cut-offs, the combination of TTV load and QF-Ag or TTV load and QF-Mg did not improve prediction of CMV viremia control compared to separate analysis of each marker but resulted in an increase of positive predictive values. The use of our cut-offs slightly improved risk prediction of CMV reactivation.

Conclusion

The combination of TTV load and QF-Ag or TTV load and QF-Mg could be useful in stratifying the risk of CMV reactivation in R+ KTR during the first post-transplant year and thereby have an impact on the duration of prophylaxis in these patients.

Clinical trial registration

ClinicalTrials.gov registry, identifier NCT02064699.

Prospects of Cytomegalovirus-Specific T-Cell Receptors in Clinical Diagnosis and Therapy

Human cytomegalovirus (HCMV) is responsible for widespread infections worldwide. In immunocompetent individuals it is typically latent, while infection or reactivation in immunocompromised individuals can result in severe clinical symptoms or even death. Although there has been significant progress in the treatment and diagnosis of HCMV infection in recent years, numerous shortcomings and developmental limitations persist. There is an urgent need to develop innovative, safe, and effective treatments, as well as to explore early and timely diagnostic strategies for HCMV infection. Cell-mediated immune responses are the primary factor controlling HCMV infection and replication, but the protective role of humoral immune responses remains controversial. T-cells, key effector cells of the cellular immune system, are critical for clearing and preventing HCMV infection. The T-cell receptor (TCR) lies at the heart of T-cell immune responses, and its diversity enables the immune system to differentiate between self and non-self. Given the significant influence of cellular immunity on human health and the indispensable role of the TCR in T-cell immune responses, we posit that the impact of TCR on the development of novel diagnostic and prognostic methods, as well as on patient monitoring and management of clinical HCMV infection, will be far-reaching and profound. High-throughput and single-cell sequencing technologies have facilitated unprecedented quantitative detection of TCR diversity. With these current sequencing technologies, researchers have already obtained a vast number of TCR sequences. It is plausible that in the near future studies on TCR repertoires will be instrumental in assessing vaccine efficacy, immunotherapeutic strategies, and the early diagnosis of HCMV infection.

Impact of cytomegalovirus immunodominant HLA-I donor-recipient matching on the incidence and features of virus DNAemia and virus-specific T-cell immune reconstitution in unmanipulated haploidentical hematopoietic stem cell transplantation

BACKGROUND

We investigated whether donor-recipient mismatch involving one or more cytomegalovirus (CMV) immunodominant (ID) human leukocyte antigen (HLA)-I alleles may impact on the degree of CMV pp65/immediate-early 1 (IE-1) T-cell reconstitution and the incidence of CMV DNAemia in patients undergoing unmanipulated haploidentical hematopoietic stem cell transplantation with high-dose posttransplant cyclophosphamide (PT/Cy-haplo).

METHODS

Multicenter observational study including 106 consecutive adult PT/Cy-haplo patients (34 CMV ID HLA-I matched and 72 mismatched). A real-time PCR was used for plasma CMV DNA load monitoring. Enumeration of CMV-specific (pp65/IE-1) interferon (IFN)-γ-producing T cells from several patients was performed by flow cytometry by days +30, +60, +90 and +180 after transplantation.

RESULTS

The cumulative incidence of CMV DNAemia, clinically significant CMV DNAemia episodes (cs-CMVi), and recurrent CMV DNAemia was comparable across CMV ID HLA-I matched and mismatched patients (71.8% vs. 80.9%, p = .95; 40.7% vs. 44.2%, p = .85; 16.4% vs. 28.1%; p = .43, respectively). The percentage of patients exhibiting detectable CMV-specific IFN-γ-producing T-cell responses (either CD8⁺ or CD4⁺ ) was similar across groups; nevertheless, significantly higher CMV-specific CD8⁺ T-cell counts were enumerated in the CMV ID HLA-I matched compared to mismatched patients by day +60 (p = .04) and +180 (p = .016) after transplantation.

CONCLUSION

CMV ID HLA-I matching may impact on the magnitude of CMV-pp65/IE-1-specific CD8⁺ T-cell reconstitution; yet, this effect seemed not to have an impact on the incidence of initial, recurrent CMV DNAemia, or cs-CMVi.

Murine cytomegalovirus downregulates ERAAP and induces an unconventional T cell response to self

The endoplasmic reticulum aminopeptidase associated with antigen processing (ERAAP) plays a crucial role in shaping the peptide-major histocompatibility complex (MHC) class I repertoire and maintaining immune surveillance. While murine cytomegalovirus (MCMV) has multiple strategies for manipulating the antigen processing pathway to evade immune responses, the host has also developed ways to counter viral immune evasion. In this study, we find that MCMV modulates ERAAP and induces an interferon γ (IFN-γ)-producing CD8+ T cell effector response that targets uninfected ERAAP-deficient cells. We observe that ERAAP downregulation during infection leads to the presentation of the self-peptide FL9 on non-classical Qa-1b, thereby eliciting Qa-1b-restricted QFL T cells to proliferate in the liver and spleen of infected mice. QFL T cells upregulate effector markers upon MCMV infection and are sufficient to reduce viral load after transfer to immunodeficient mice. Our study highlights the consequences of ERAAP dysfunction during viral infection and provides potential targets for anti-viral therapies.

Human Cytomegalovirus UL23 Antagonizes the Antiviral Effect of Interferon-γ by Restraining the Expression of Specific IFN-Stimulated Genes

Interferon-γ (IFN-γ) is a critical component of innate immune responses in humans to combat infection by many viruses, including human cytomegalovirus (HCMV). IFN-γ exerts its biological effects by inducing hundreds of IFN-stimulated genes (ISGs). In this study, RNA-seq analyses revealed that HCMV tegument protein UL23 could regulate the expression of many ISGs under IFN-γ treatment or HCMV infection. We further confirmed that among these IFN-γ stimulated genes, individual APOL1 (Apolipoprotein-L1), CMPK2 (Cytidine/uridine monophosphate kinase 2), and LGALS9 (Galectin-9) could inhibit HCMV replication. Moreover, these three proteins exhibited a synergistic effect on HCMV replication. UL23-deficient HCMV mutants induced higher expression of APOL1, CMPK2, and LGALS9, and exhibited lower viral titers in IFN-γ treated cells compared with parental viruses expressing full functional UL23. Thus, UL23 appears to resist the antiviral effect of IFN-γ by downregulating the expression of APOL1, CMPK2, and LGALS9. This study highlights the roles of HCMV UL23 in facilitating viral immune escape from IFN-γ responses by specifically downregulating these ISGs.

Infection, Rejection, and the Connection

Solid organ transplantation is a life-saving treatment for people with end-stage organ disease. Immune-mediated transplant rejection is a common complication that decreases allograft survival. Although immunosuppression is required to prevent rejection, it also increases the risk of infection. Some infections, such as cytomegalovirus and BK virus, can promote inflammatory gene expression that can further tip the balance toward rejection. BK virus and other infections can induce damage that resembles the clinical pathology of rejection, and this complicates accurate diagnosis. Moreover, T cells specific for viral infection can lead to rejection through heterologous immunity to donor antigen directly mediated by antiviral cells. Thus, viral infections and allograft rejection interact in multiple ways that are important to maintain immunologic homeostasis in solid organ transplant recipients. Better insight into this dynamic interplay will help promote long-term transplant survival.

New trends in the management of cytomegalovirus infection after allogeneic hematopoietic cell transplantation: a survey of the Infectious Diseases Working Pary of EBMT

The management of cytomegalovirus (CMV) infection was assessed with a survey performed in 2020 by the Infectious Diseases Working Party of European Society for Blood and Marrow Transplantation (EBMT). One-hundred-eighty of the 579 EBMT centres (31%) responded. CMV monitoring with quantitative PCR for CMV-DNAemia was used by 97% of centres while the duration of monitoring was variable according to the patient immune recovery and the ongoing immunosuppressive therapy. CMV prophylaxis for high-risk patients was used in 101 (56%) of centres: letermovir in 62 centres (61%), aciclovir/valaciclovir in 19 centres (19%), ganciclovir/valganciclovir in 17 centres (17%), foscarnet in 3 (3%). The most used trigger for pre-emptive therapy was a threshold of >10³ copies/ml or >10³ IU/ml. Ganciclovir/valganciclovir confirmed the preferred first line treatment both for pre-emptive and CMV disease therapy. CMV-cytotoxic T-cells were used mainly in the setting of relapsing/refractory CMV disease. Forty-eight centres reported CMV refractory/resistant infection due to mutated CMV strain.This survey showed that letermovir prophylaxis is adopted by more than half of centres using a prophylaxis approach for CMV infection. How letermovir prophylaxis will modify other important pillars of daily CMV management, such as frequency of CMV-DNAemia monitoring and preemptive therapy, remain a matter of investigation.

The association between antigenemia, histology with immunohistochemistry, and mucosal PCR in the diagnosis of ulcerative colitis with concomitant human cytomegalovirus infection

BACKGROUND

Human cytomegalovirus (HCMV) colitis can be involved in active ulcerative colitis (UC) in patients refractory to steroid and immunosuppressive drugs. Histological examination with colonic biopsy specimens and antigenemia assays are the standard tests for diagnosing HCMV enterocolitis, and we have previously reported the usefulness of mucosal polymerase chain reaction (PCR) methods. However, the associations among histopathological tests, antigenemia assays, and mucosal PCR are unknown.

METHODS

We retrospectively analyzed 82 UC patients who underwent mucosal biopsy from inflamed colonic tissues for histological evaluation and mucosal PCR to detect HCMV. We analyzed the relationships between the HCMV-DNA copy number in colonic mucosa and other HCMV tests.

RESULTS

In total, 131 HCMV mucosal PCR tests from 82 UC patients were positive. The HCMV-DNA copy number was significantly higher in patients with positive immunohistochemistry (IHC) (p < 0.01) and was correlated with the number of positive cells for the antigenemia (C7-HRP, p < 0.01; C10/11, p < 0.01). Receiver operating characteristic curve analysis confirmed 1300 copies/μg of HCMV-DNA as the best diagnostic cut-off value to predict positive results of antigenemia (area under the curve = 0.80, 95% CI 0.68-0.93). HCMV-DNA copy number also correlated with the total UCEIS score (p = 0.013) and the bleeding score (p = 0.014). For each individual patient, a positive correlation between the change in total UCEIS score and HCMV-DNA copy number was observed (p = 0.040).

CONCLUSION

The antigenemia assay and histopathological test with IHC were significantly associated with the HCMV-DNA copy number in colonic tissues. Moreover, endoscopic examination with the UCEIS can help diagnose the HCMV colitis in UC patients.

Altered serum human cytomegalovirus microRNA levels are common and closely associated with the inflammatory status in patients with fever

Background

Fever has a complicated etiology, and diagnosing its causative factor is clinically challenging. Human cytomegalovirus (HCMV) infection causes various diseases. However, the clinical relevance, prevalence, and significance of HCMV microRNAs (miRNA) in association with fever remain unclear. In the present study, we analyzed the HCMV miRNA expression pattern in the serum of patients with fever and evaluate its clinical associations with occult HCMV infection status in immune disorders.

Methods

We included serum samples from 138 patients with fever and 151 age-gender-matched controls in this study. First, the serum levels of 24 HCMV miRNAs were determined using a hydrolysis probe-based stem-loop quantitative reverse transcription polymerase chain reaction (RT-qPCR) assay in the training set. The markedly altered miRNAs were verified in the validation and testing sets. The serum HCMV IgG/IgM and DNA titers in the testing cohort were also assessed using enzyme-linked immunosorbent assay (ELISA) and RT-qPCR, respectively.

Results

The majority of HCMV miRNAs were markedly upregulated in the serum of fever patients. We selected the five most significantly altered HCMV miRNAs: hcmv-miR-US4-3p, hcmv-miR-US29-3p, hcmv-miR-US5-2-3p, hcmv-miR-UL112-3p, and hcmv-miR-US33-3p for validation. These miRNAs were also significantly elevated in the serum of fever patients in the validation and testing sets compared with the controls. Logistic regression analysis revealed that the five miRNAs were novel potential risk factors for fever. Notably, the serum levels of four of the five confirmed HCMV miRNAs were significantly associated with blood C-reaction protein concentrations. Moreover, the five HCMV miRNA levels were closely correlated with the HCMV DNA titers in the testing cohort.

Conclusion

HCMV infection and activation are common in fever patients and could be novel risk factors for fever. These differentially expressed HCMV miRNAs could enable HCMV activation status monitoring in immune disorders.

IL-10-Secreting CD8+ T Cells Specific for Human Cytomegalovirus (HCMV): Generation, Maintenance and Phenotype

HCMV-specific CD8⁺ T-cells are potent anti-viral effector cells in HCMV infected individuals, but evidence from other viral infections suggests that CD8⁺ T-cells can also produce the immunomodulatory cytokine IL-10. In this work we show that there are HCMV-specific IL-10 CD8⁺ T-cell responses in a cohort of individuals aged 23-76 years of age, predominantly directed against the HCMV proteins known to be expressed during latent infections as well as towards the proteins US3 and pp71. The analysis of HCMV-specific responses established during primary infection has shown that the IL-10 responses to US3 and pp71 HCMV proteins are detectable in the first weeks post infection, but not the responses to latency-associated proteins, and this IL-10 response is produced by both CD8⁺ and CD4⁺ T-cells. Phenotyping studies of HCMV-specific IL-10⁺ CD8⁺ T-cells show that these are CD45RA⁺ effector memory cells and co-express CD28 and CD57, however, the expression of the inhibitory receptor PD-1 varied from 90% to 30% between donors. In this study we have described for the first time the HCMV-specific IL-10 CD8⁺ T-cell responses and have demonstrated their broad specificity and the potential immune modulatory role of the immune response to HCMV latent carriage and periodic reactivation.

Acute cytomegalovirus hepatitis in an immunocompetent patient: A case report

BACKGROUND

Cytomegalovirus (CMV) infection is usually subclinical and asymptomatic in the healthy population, whereas severe complications occur in immunocompromised patients.

CASE SUMMARY

In this case report, we described a rare case of acute CMV hepatitis in a 35-year-old male immunocompetent patient who presented with a history of week-long intermittent fever with nonspecific constitutional symptoms. Acute hepatitis was suspected according to the initial serological tests. After ruling out other etiologies, including viral hepatitis A, B, C, drug, alcohol, autoimmune, and Wilson disease, acute CMV hepatitis was diagnosed based on positive CMV IgM and DNA quantitative tests. Because there was no any local acute hepatitis E reported in Taiwan, so hepatitis E was not checked. The patient recovered both clinically and serologically with symptomatic management and without antiviral therapy within 12 days from the onset of symptom.

CONCLUSION

In conclusion, a diagnosis of CMV infection should be considered when nonspecific prodromal symptoms occur in acute hepatitis with an uncertain etiology. Antiviral therapy should not be used in immunocompetent patient who had no decompensation of the liver, such as this patient. Widely available noninvasive tests for CMV can facilitate early diagnosis if used appropriately. Harm–benefit analysis is essential before using antiviral therapy in immunocompetent patients.

Low dose thymoglobulin versus basiliximab in cytomegalovirus positive kidney transplant recipients: Effectiveness of preemptive cytomegalovirus modified strategy

BACKGROUND

We performed a retrospective trial to determine asymptomatic CMV reactivation and CMV disease in kidney allograft recipients with positive CMV serostatus.

METHODS

Preemptive modified strategy under low dose thymoglobulin versus basiliximab induction was evaluated. Patients were monitored by CMV-polymerase chain reaction (PCR); if the viral load was >4000copies/μl, they received valganciclovir adjusted for their renal function.

RESULTS

132 recipients were included in the study, 84 and 48 receiving basiliximab and thymoglobulin induction respectively, and followed up for 12 months. Asymptomatic CMV reactivation was significantly higher for thymoglobulin (77.1% vs. 16.7%, p<0.001). Treatment groups had similar rates of CMV disease (3.6% vs. 2.1%, p 0.538). The significant difference in asymptomatic CMV reactivation between two treatment groups did not have any impact on 1 year graft function (71±26ml/min vs. 74±19ml/min; p=0.475) and no histological differences in protocol biopsies were observed among patients with asymptomatic CMV reactivation vs those without CMV reactivation.

CONCLUSIONS

Due to the high asymptomatic CMV reactivation incidence in patients who received thymoglobulin induction, our results suggest that valganciclovir prophylaxis may be advantageous in CMV seropositive renal transplant recipients after low dose thymoglobulin induction. A preemptive strategy appeared to significantly reduce the likelihood of CMV disease in both groups. Rejection risk and negative impact in renal function associated with asymptomatic CMV reactivation was not found in our series.

Identification and characterization of human cytomegalovirus-encoded circular RNAs

Circular RNA (circRNA) exists extensively and plays essential roles in serving as microRNA (miRNA) or protein sponges and protein scaffolding in many organisms. However, the profiles and potential functions of the virus-encoded circRNA, including human cytomegalovirus (HCMV)-encoded circular RNAs, remain unclear. In the present study, HCMV-encoded circRNAs profile in human embryonic lung fibroblasts (HELF) with lytic infection was investigated using RNA deep sequencing and bioinformatics analysis. In total, 629 HCMV-encoded circRNAs were identified with various expression patterns in our results. The full sequences and alternative splicings of circUS12, circUL55, and circUL89 were verified by reverse transcriptase-PCR (RT-PCR) with divergent primers followed and Sanger sequencing. Transcription of circUL89 was validated by Northern blot. The HCMV-encoded circRNA-miRNA network analyses revealed the potential function of HCMV-encoded circRNAs during HCMV infection in HELFs. Collectively, HCMV infection deduced abundant HCMV-associated circRNAs during infection, and the HCMV-encoded circRNAs might play important roles in benefiting HCMV infection.

Human cytomegalovirus: a survey of end-organ diseases and diagnostic challenges in solid organ transplant recipients

PURPOSE OF REVIEW

Human cytomegalovirus (CMV) infection is one of the most important infectious complications in solid organ transplant (SOT) recipients, leading to significant morbidity and mortality. Therefore, early detection and prompt treatment are imperative to improve transplant outcomes. This article highlights the clinical characteristics of the most common CMV end-organ diseases in SOT recipients and their diagnostic modalities and challenges.

RECENT FINDINGS

CMV can cause a variety of end-organ diseases in SOT recipients. Although CMV nucleic acid amplification by polymerase chain reaction (PCR) is frequently employed to detect CMV reactivation or infection, its predictive value for various CMV end-organ diseases remains uncertain. Given the limitation of PCR or other noninvasive tests, confirmation of CMV end-organ disease may require tissue biopsy, which may not be feasible or available, or may cause untoward complications.

SUMMARY

The utility of PCR to diagnose CMV end-organ disease is limited. As CMV can infect any organ system(s), clinicians caring for SOT recipients need to maintain vigilance for any signs and symptoms of end-organ disease to allow early recognition and prompt treatment. Invasive procedures might be needed to confirm the diagnosis and minimize the empirical use of antiviral therapy that may have substantial drug toxicities.

Effect of Cytomegalovirus on the Immune System: Implications for Aging and Mental Health

Human cytomegalovirus (HCMV) is a major modulator of the immune system leading to long-term changes in T-lymphocytes, macrophages, and natural killer (NK) cells among others. Perhaps because of this immunomodulatory capacity, HCMV infection has been linked with a host of deleterious effects including accelerated immune aging (premature mortality, increased expression of immunosenescence-linked markers, telomere shortening, speeding-up of epigenetic "clocks"), decreased vaccine immunogenicity, and greater vulnerability to infectious diseases (e.g., tuberculosis) or infectious disease-associated pathology (e.g., HIV). Perhaps not surprisingly given the long co-evolution between HCMV and humans, the virus has also been associated with beneficial effects, such as increased vaccine responsiveness, heterologous protection against infections, and protection against relapse in the context of leukemia. Here, we provide an overview of this literature. Ultimately, we focus on one other deleterious effect of HCMV, namely the emerging literature suggesting that HCMV plays a pathophysiological role in psychiatric illness, particularly depression and schizophrenia. We discuss this literature through the lens of psychological stress and inflammation, two well-established risk factors for psychiatric illness that are also known to predispose to reactivation of HCMV.