Search Results (139)

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disorder characterized by the destruction of insulin-producing pancreatic beta cells, resulting in lifelong insulin dependence. While genetic susceptibility—particularly human leukocyte antigen (HLA) class II alleles—is a major risk factor, accumulating evidence implicates viral infections as potential environmental triggers in disease onset and progression. This narrative review synthesizes current findings on the role of viral pathogens in T1DM pathogenesis. Enteroviruses, especially Coxsackie B strains, are the most extensively studied and show strong epidemiological and mechanistic associations with beta-cell autoimmunity. Large prospective studies—including Diabetes Virus Detection (DiViD), The environmental determinans of diabetes in the young (TEDDY), Miljøfaktorer i utvikling av type 1 diabetes (MIDIA), and Diabetes Autoimmunity Study in the Young (DAISY)—consistently demonstrate correlations between enteroviral presence and the initiation or acceleration of islet autoimmunity. Other viruses—such as mumps, rubella, rotavirus, influenza A (H1N1), and SARS-CoV-2—have been investigated for their potential involvement through direct cytotoxic effects, immune activation, or molecular mimicry. Interestingly, certain viruses like varicella-zoster virus (VZV) and cytomegalovirus (CMV) may exert modulatory or even protective influences on disease progression. Proposed mechanisms include direct beta-cell infection, molecular mimicry, bystander immune activation, and dysregulation of innate and adaptive immunity. Although definitive causality remains unconfirmed, the complex interplay between genetic predisposition, immune responses, and viral exposure underscores the need for further mechanistic research. Elucidating these pathways may inform future strategies for targeted prevention, early detection, and vaccine or antiviral development in at-risk populations. Full article

Human cytomegalovirus (HCMV) establishes lifelong latency in the host, with the bone marrow (BM) CD34+ cells serving as a key reservoir. To investigate tissue-specific immune responses to CMV, we analysed paired peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMNCs) from HCMV-seropositive donors using multiparametric flow cytometry and cytokine FluroSpot assays. We assessed immune cell composition, memory T cell subsets, cytokine production, cytotoxic potential, activation marker expression, and checkpoint inhibitory receptor (CIR) profiles, both ex vivo and following stimulation with lytic and latent HCMV antigens. BMMNCs were enriched in CD34+ progenitor cells and exhibited distinct T cell memory subset distributions. HCMV-specific responses were compartmentalised: IFN-γ responses predominated in PBMCs following lytic antigen stimulation, while IL-10 and TNF-α responses were more prominent in BMMNCs, particularly in response to latent antigens. US28-specific T cells in the BM showed elevated expression of CD39, PD-1, BTLA, CTLA-4, ICOS, and LAG-3 on CD4+ T cells and increased expression of PD-1, CD39, BTLA, TIGIT, LAG-3, and ICOS on CD8+ T cell populations, suggesting a more immunoregulatory phenotype. These findings highlight functional and phenotypic differences in HCMV-specific T cell responses between blood and bone marrow, underscoring the role of the BM niche in shaping antiviral immunity and maintaining viral latency. Full article

Background: Cytomegalovirus (CMV) colitis is commonly seen in patients who are immunodeficient or have inflammatory bowel disease. Among the gastrointestinal sites affected by CMV, the colon is the most frequently affected, though rectal involvement is relatively rare. Reactivated CMV proctitis primarily occurs in elderly patients with comorbidities and is quite uncommon in immunocompetent individuals. Patients with reactivated CMV typically present with symptoms such as diarrhea, hematochezia, or tenesmus. Case presentation: We report a case of a female patient with uncontrolled diabetes who presented to the clinic complaining of perianal pain. She had no history of diarrhea or rectal bleeding. Lower GI endoscopy reported a small, localized, approximately 0.5 cm swelling in the proximal anal canal in addition to sigmoid diverticulosis. The biopsy revealed a small ulcer at the anorectal junction caused by CMV and confirmed by immunohistochemistry. Unfortunately, the patient was lost to follow-up before antiviral therapy could be initiated. Conclusions: This case highlights an uncommon presentation of reactivated CMV proctitis in an older diabetic patient presenting solely with perianal pain. Clinicians should maintain a high index of suspicion for CMV infection in elderly patients with comorbidities, even when classical colitis symptoms are absent, to avoid delayed diagnosis and management. Full article

Background/Objectives: The physiological activation of cytotoxic CD8^pos T cells (CTLs) relies on the engagement of the TCR/CD3 complex with cognate peptide-HLA class I (pHLA-I) on target cells, triggering cell lysis with appropriate cytokine release and minimized off-target toxicity. In contrast, current immunotherapies for CD19-expressing hematological malignancies, such as chimeric antigen receptor (CAR) T cells and bispecific T cell engagers (BiTEs), bypass TCR/pHLA interactions, resulting in CTL hyperactivation and excessive cytokine release, which frequently cause severe immune-related adverse events (irAEs). Thus, there is a pressing need for T cell-based therapies that preserve physiological activation while maintaining antitumor efficacy. Methods: To address this, we developed CD19-ReTARG^TPR, a novel fusion protein consisting of the immunodominant cytomegalovirus (CMV) pp65-derived peptide TPRVTGGAM (TPR) covalently presented by a soluble HLA-B*07:02/β2-microglobulin complex fused to a high-affinity CD19-targeting Fab antibody fragment. The treatment of CD19-expressing cancer cells with CD19-ReTARG^TPR makes them recognizable for pre-existing anti-CMV_pp65 CTLs via physiological TCR-pHLA engagement. Results: Our preclinical data demonstrate that CD19-ReTARG^TPR efficiently redirects anti-CMV CTLs to eliminate CD19-expressing cancer cells, including both established cell lines and primary chronic lymphocytic leukemia (CLL) cells. Unlike CD19-directed CAR T cells or the CD19/CD3 BiTE blinatumomab, CD19-ReTARG^TPR mediated robust cytotoxic activity without triggering supraphysiological cytokine release. Importantly, this approach retained efficacy even against cancer cells with low CD19 expression. Conclusions: In summary, we provide a robust proof-of-concept study and show that CD19-ReTARG^TPR offers a promising alternative strategy for T cell redirection, enabling the selective and effective killing of CD19-expressing malignancies while minimizing cytokine-driven toxicities through physiological CTL activation pathways. Full article

Background: Human cytomegalovirus (HCMV) is the leading cause of congenital and acquired viral infections in newborns. While acquired infections are often asymptomatic, premature infants—especially those born before 30 weeks of gestation or with a very low birth weight (<1500 g)—are at an increased risk for severe infections. These can manifest as thrombocytopenia, liver failure, sepsis-like symptoms, and, in rare cases, death. HCMV is transmitted through various human secretions, including breast milk, which is the optimal feeding method for premature infants. Methods: We present five premature neonates, born between 23 and 26 weeks of gestation, each with a distinct clinical presentation of acquired HCMV infection. Results: All infants tested negative for congenital CMV infection via molecular urine testing within the first three weeks of life. Acquired infection was diagnosed between the second and third month of life, with symptoms such as septic shock, persistent thrombocytopenia, and signs of liver failure. Each infant received antiviral treatment along with regular viral load monitoring. Unfortunately, one patient died due to complications of prematurity. The remaining infants were discharged and continue to receive follow-up care in an outpatient clinic. Conclusions: These cases of postnatally acquired CMV infection aim to increase awareness of its highly heterogeneous and nonspecific clinical presentation, which may result in an incorrect, delayed, or concealed diagnosis. Currently, there are no clear guidelines on how to manage the presence of the virus in maternal breast milk, particularly for premature infants. It should be recommended to perform a molecular CMV test in all breast-fed preterm infants who present with sepsis-like symptoms, thrombocytopenia, liver failure, or other organ involvement. In case of a confirmed aCMV diagnosis, appropriate treatment should be introduced. Full article

Human cytomegalovirus (CMV) is the leading cause of congenital infections, often leading to mental retardation and neurological disorders. It is a major public health priority to develop a vaccine for preventing and controlling human CMV infection. In this report, we generated an oral Salmonella-based vaccine to express the M33 protein of murine cytomegalovirus (MCMV) and investigated the anti-MCMV immune responses induced in mice immunized with this vaccine. Compared to those administered with phosphate-buffered saline (PBS) or a control vaccine without M33 expression, mice immunized with the vaccine expressing the M33 protein exhibited a remarkable induction of antiviral serum IgG and mucosal IgA humoral responses and a significant elicitation of antiviral T cell responses. Successful inhibition of viral growth in lungs, spleens, livers, and salivary glands was also found in the vaccinated animals compared to the PBS-treated animals or those immunized with the control vaccine without M33 expression. Furthermore, substantial protection against MCMV challenge was observed in mice immunized with the vaccine. Thus, Salmonella-based vaccine expressing MCMV M33 can induce anti-MCMV effective immune responses and protection. Our study implies that attenuated Salmonella expressing human CMV antigens, including its homologue to M33, may represent promising oral anti-CMV vaccine candidates. Full article

Cytomegalovirus (CMV) colitis, a complication in patients with inflammatory bowel disease (IBD), particularly ulcerative colitis (UC), is a significant diagnostic and therapeutic challenge due to its overlap with IBD flares. CMV reactivation in IBD is driven by chronic inflammation, compromised immune function, and use of immunosuppressive agents like corticosteroids. Risk factors include older age, pancolitis, and severe disease. Diagnosis hinges on endoscopy and histology, with tissue biopsy and immunohistochemistry as the gold standard. Quantitative tissue PCR may aid in differentiating latent from active infection. CMV colitis exacerbates IBD symptoms, prolongs hospitalization, and increases colectomy rates. Antiviral therapy, primarily ganciclovir, improves outcomes in patients with corticosteroid-refractory UC. Treatment focuses on tapering corticosteroids, optimizing biologic therapies such as infliximab, and a careful application of antivirals tailored to disease severity and viral load. Further research is needed to refine diagnostic thresholds and treatment strategies to mitigate CMV’s impact on IBD prognosis. Early identification and individualized management are critical to improving clinical outcomes and reducing morbidity. Full article

Belatacept is a recombinant fusion protein used in renal transplant recipients, particularly when side effects from standard immunosuppressants occur. It offers a superior renal safety profile and is associated with better long-term renal graft outcomes. However, belatacept has been linked to atypical presentations of cytomegalovirus (CMV) infections, characterized by a prolonged and unpredictable course of viremia. We report a case involving a middle-aged African American female who developed acute kidney injury while on tacrolimus and was subsequently switched to belatacept. During treatment with belatacept, she experienced persistent and erratic CMV viremia lasting 58 weeks. The viremia showed an incomplete response to first-line antiviral therapy with valganciclovir, and the use of the novel antiviral agent maribavir also failed to achieve long-lasting viremic clearance. The resolution of the viremia was ultimately achieved only after discontinuing belatacept while continuing maribavir therapy. This case and literature review underscores the need for clinicians to remain vigilant for atypical CMV infections in renal transplant recipients treated with belatacept. If the complete clearance of viremia cannot be achieved despite the use of different antiviral agents, consideration should be given to modifying immunosuppressive therapy. Full article

Herpesviruses are prevalent pathogens affecting lactating women, yet the safety and efficacy of antiviral therapies in this population remain underexplored. This systematic review evaluates the safety and efficacy of antiviral therapies for Herpesviridae infections, including CMV, VZV, EBV, and HSV, in lactating mothers. A comprehensive literature search was conducted using PubMed, Cochrane Library, and Scopus, alongside specialized databases like LactMed. Twelve studies were included, comprising three randomized control trials, five observational studies, and four case reports. Quality assessment using Joanna Briggs Institute tools indicated moderate-to-high methodological quality for the trials and consistent strengths in case reports, though some limitations were noted. Results suggest that antiviral agents, particularly acyclovir and valacyclovir, are generally safe for breastfeeding mothers, with minimal infant exposure and low risk of adverse effects. However, the virologic benefits appear modest, and most studies focused on HIV co-infected populations, limiting generalizability to lactating women without HIV. In conclusion, while current evidence supports the use of specific antivirals during lactation, there is a critical need for further research to address existing knowledge gaps and optimize treatment strategies for both mothers and infants. Full article

Human cytomegalovirus (HCMV) is a high-risk pathogen in immunocompromised individuals, especially in transplant recipients. HCMV viremia must be monitored, and frequently, patients are treated with antiviral agents. HCMV has a variety of strategies to modulate host antiviral responses, and one important player is a viral homolog of the cellular interleukin-10 (cIL-10). The viral UL111A gene produces several HCMV IL-10 transcripts and protein isoforms through alternative splicing. The cmvIL-10 (isoform A) has similar properties to cIL-10, while LAcmvIL-10 (isoform B) has more restricted biological properties. Other isoforms are produced (C to H) but have unknown functions. Here, we investigated the expression of the most abundant transcripts, cmvIL-10 and LAcmvIL-10, in productively and latently infected cells and in peripheral blood mononuclear cells from renal transplant recipients up to 60 days post-transplantation. This study investigated HCMV cmvIL-10 and LAcmvIL-10 transcription profiles in vitro, in productive and latent infection, and in vivo, in peripheral blood mononuclear cells (PBMCs) of renal transplant patients. In vitro, both cmvIL-10 and LAcmvIL-10 transcripts were detected in both types at high levels and low levels in MRC-5 and latent infected (CD14+). When PBMCs from transplant patients were analyzed, LAcmvIL-10 was detected mostly sporadically and in only a few patients, while cmvIL-10 was found in all patients at all time points. Furthermore, it was observed in PBMCs that expression of cmvIL-10 was positively associated with an increase in viral DNA detection in the subsequently collected sample, indicating that expression of cmvIL-10 might precede viral DNA replication. These results contribute to the understanding of HCMV biology in different phases of infection. In addition, our initial analysis suggests that monitoring cmvIL-10, along with viral DNA, could improve early detection of HCMV reactivation in transplant recipients. Full article

Cytomegalovirus (CMV), the largest of the herpes viruses, is a widespread virus that commonly infects people of all ages. CMV can cause a spectrum of clinical manifestations, ranging from asymptomatic infection to severe disease, particularly in immunocompromised hosts. However, postnatal and acquired CMV infections in immunocompetent children remain under-documented in the literature. In this review, we examine studies published over the past decade to explore the clinical manifestations of CMV infections in the pediatric population, focusing on the variety of symptoms and the severity with which the infection can present. Papers published between 1 January 2014 and 2 December 2024 were selected from PubMed/MEDLINE, Embase, Scopus, and Web of Science. The search was conducted using the following keywords: “cytomegalovirus”, “child”, and “immunocompetent”. The target population ranged from 0 to 17 years of age, with congenital and perinatal infections excluded. Despite the clinical significance of CMV in immunocompetent infants and children, there is a lack of consensus on the use and duration of antiviral therapy. This article aims to enhance clinicians’ understanding of the various presentations of CMV infection in immunocompetent children, with the goal of facilitating earlier diagnosis and appropriate management. The reviewed papers indicated that postnatal CMV results in liver symptoms in 67% of cases, followed by hematological disorders and gastrointestinal pathology. In older children, primary infection leads to liver disease in 51% of cases, with greater neurological and pulmonary involvement compared to that in infants. By highlighting the wide-ranging clinical effects of CMV, we hope to improve physicians’ ability to recognize and subsequently treat this often overlooked condition in pediatric patients. Full article

Background: Human cytomegalovirus (CMV) remains an important pathogen, especially for immunocompromised patients such as solid organ and hematopoietic stem cell recipients. Viral genomic mutations conferring drug resistance are an important impediment to effective CMV management and frequently lead to use of alternative antiviral drugs to treat CMV disease. Methods: Results from 1459 de-identified patient samples with both UL54 and UL97 sequencing results were analyzed for ganciclovir (GCV) and maribavir (MBV) resistance mutations. Genomic sequencing was performed by the Sanger method and resistance mutations were identified by comparison to CMV reference strain AD169. Results: Ganciclovir resistance was identified in 379 of 1459 (25.98%) of the samples tested, with most resistance-conferring mutations present in viral gene UL97. A total of 121 of 1459 (8.29%) samples had MBV resistance mutations, and 84 (69.42%) of the 121 samples with MBV resistance also had GCV resistance mutations. Of the 84 samples with resistance to both MBV and GCV, 35 (41.67%) had a single UL97 mutation conferring resistance to both drugs, either C480F or F342Y. The overall prevalence of C480F was increased relative to an earlier analysis of samples from this reference laboratory. Conclusions: Although a high prevalence of CMV resistance mutations was identified, this must be taken in the context of healthcare providers submitting samples from patients with suspected CMV resistance. Most MBV-resistant samples were also resistant to GCV, suggesting that use of MBV as an alternative to GCV may benefit from genotypic resistance testing to achieve the effective control of CMV disease. Full article

Cardiac glycosides (CGs), historically used to treat heart failure and arrhythmias, bind to the α subunit of the Na⁺/K⁺-ATPase pump and inhibit its activity. Their anticancer and antiviral activities are of interest. The α subunit of the Na⁺/K⁺-ATPase pump has four isoforms (α1–4), each with unique tissue distribution and expression pattern; their contributions to antiviral activities have not been studied. We previously reported that CGs inhibit human CMV (HCMV) in vitro but not mouse CMV (MCMV). In addition to the low affinity of mouse α1 for CGs, we hypothesized that other isoforms contribute to the anti-CMV activities of CGs. We show here that infection with HCMV significantly induced α3 in human foreskin fibroblasts, while MCMV did not induce mouse α3. Infection with guinea pig CMV (GPCMV) in GP fibroblasts also induced α3, and CGs inhibited GPCMV replication. HCMV inhibition with digitoxin reduced α3 expression. The concentration-dependent inhibition of HCMV with digitoxin analogs also correlated with α3 expression. Intriguingly, α3 was localized to the nucleus, and changes in its expression during infection and digitoxin treatment were mostly limited to the nucleus. At 4 h post-infection, α3 colocalized with immediate early 1 (IE1) and the promyelocytic leukemia protein (PML). An interaction of α3-PML-IE1 at 24 h post-infection was disrupted by digitoxin. The mRNA levels of IE1, major immediate early promoter (MIEP)-derived IE, and antiviral cytokines were reduced in infected digitoxin-treated cells. Summarized, these findings suggest a new role for α3 in the anti-HCMV activities of CGs via nuclear antiviral signaling pathways. Full article

Cytomegaloviruses (CMVs) encode viral G-protein-coupled receptors (vGPCRs) that have diverged from their cellular homologues to perform new functions. Human cytomegalovirus (HCMV) encodes four vGPCRs: UL33, UL78, US27, and US28, which contribute to viral pathogenesis, cellular signalling, and latency. While the role of US28 in chemokine signalling and viral latency is well characterised, the functions of other vGPCRs remain incompletely understood. Rodent cytomegaloviruses only have homologues to UL33 and UL78, while primates have two to five additional GPCRs which are homologues of US27 and US28. Different CMVs appear to have evolved vGPCRs with functions specific to infection of their respective host. As non-human CMVs are used as model organisms to understand clinical cytomegalovirus disease and develop vaccines and antivirals, understanding the differences between these vGPCRs helps researchers understand critical differences between their models. This review aims to address the differences between CMV vGPCRs, and how these differences may affect models of CMV disease to facilitate future research. Full article

Cytomegalovirus (CMV) infection during pregnancy is the leading cause of congenital infection subsequent to viral transplacental transmission. CMV placental infection can contribute to the development of adverse outcomes likely through placental dysfunction. This case report shows the potential utility of angiogenic markers, such as placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1), in assessing CMV-related placental involvement and monitoring the effect of antiviral therapy on placental function, and highlights the possibility of integrating these markers into the clinical management of CMV infection. Full article