Outcomes of Corneal Transplantation for Herpetic Keratitis: A Narrative Review.

Herpes simplex virus (HSV) is one of the most common etiologic agents of corneal disease and a significant cause of corneal blindness worldwide. Although most cases can be successfully managed with medical therapy, HSV keratitis associated with visually significant stromal scarring often requires corneal transplantation for visual rehabilitation. While penetrating keratoplasty (PK) represented the traditional keratoplasty technique, the past few decades have seen a shift towards lamellar keratoplasty procedures, including deep anterior lamellar keratoplasty and mushroom keratoplasty. This paper describes the current surgical techniques and perioperative antiviral prophylaxis regimen for herpetic keratitis and reviews their postoperative clinical outcomes.

Toward the Eradication of Herpes Simplex Virus: Vaccination and Beyond.

Herpes simplex virus (HSV) has coevolved with Homo sapiens for over 100,000 years, maintaining a tenacious presence by establishing lifelong, incurable infections in over half the human population. As of 2024, an effective prophylactic or therapeutic vaccine for HSV remains elusive. In this review, we independently screened PubMed, EMBASE, Medline, and Google Scholar for clinically relevant articles on HSV vaccines. We identified 12 vaccines from our literature review and found promising candidates across various classes, including subunit vaccines, live vaccines, DNA vaccines, and mRNA vaccines. Notably, several vaccines-SL-V20, HF10, VC2, and mRNA-1608-have shown promising preclinical results, suggesting that an effective HSV vaccine may be within reach. Additionally, several other vaccines such as GEN-003 (a subunit vaccine from Genocea), HerpV (a subunit vaccine from Agenus), 0ΔNLS/RVx201 (a live-attenuated replication-competent vaccine from Rational Vaccines), HSV 529 (a replication-defective vaccine from Sanofi Pasteur), and COR-1 (a DNA-based vaccine from Anteris Technologies) have demonstrated potential in clinical trials. However, GEN-003 and HerpV have not advanced further despite promising results. Continued progress with these candidates brings us closer to a significant breakthrough in preventing and treating HSV infections.

Role of Neurotropic Viruses in Brain Metastasis of Breast Cancer: Mechanisms and Therapeutic Implications.

Neurotropic viruses have been implicated in altering the central nervous system microenvironment and promoting brain metastasis of breast cancer through complex interactions involving viral entry mechanisms, modulation of the blood-brain barrier, immune evasion, and alteration of the tumour microenvironment. This narrative review explores the molecular mechanisms by which neurotropic viruses such as Herpes Simplex Virus, Human Immunodeficiency Virus, Japanese Encephalitis Virus, and Rabies Virus facilitate brain metastasis, focusing on their ability to disrupt blood-brain barrier integrity, modulate immune responses, and create a permissive environment for metastatic cell survival and growth within the central nervous system. Current therapeutic implications and challenges in targeting neurotropic viruses to prevent or treat brain metastasis are discussed, highlighting the need for innovative strategies and multidisciplinary approaches in virology, oncology, and immunology.

Helicase-primase inhibitors for the treatment of herpes simplex virus infections - patent evaluation of WO2023/225162 from Gilead Sciences Inc.

Helicase-primase is an interesting target for small-molecule therapy of herpes simplex virus (HSV) infections. With amenamevir already approved for varicella-zoster virus and herpes simplex in Japan and with pritelivir's granted breakthrough therapy designation for the treatment of acyclovir-resistant HSV infections in immunocompromised patients, the target has sparked interest in helicase-primase inhibitors (HPIs). Here, we analyze the first patent application from Gilead in this field, which pursued a me-too approach combining elements from an old Bayer together with a recent Medshine HPI application (which covers the Phaeno Therapeutics drug candidate HN0037). The asset was contributed to Assembly Biosciences, where it is under development as ABI-1179 at the investigational new drug (IND) enabling stage for high-recurrence genital herpes. A structure proposal for indolinoyl derivative ABI-1179 is presented, showing its potential opportunities and limitations compared to other HPIs.

Oncolytic virotherapy augments self-maintaining natural killer cell line cytotoxicity against neuroblastoma.

BACKGROUND: Neuroblastoma is the most common extracranial solid tumor in children and accounts for 15% of pediatric cancer related deaths. Targeting neuroblastoma with immunotherapies has proven challenging due to a paucity of immune cells in the tumor microenvironment and the release of immunosuppressive cytokines by neuroblastoma tumor cells. We hypothesized that combining an oncolytic Herpes Simplex Virus (oHSV) with natural killer (NK) cells might overcome these barriers and incite tumor cell death. METHODS: We utilized MYCN amplified and non-amplified neuroblastoma cell lines, the IL-12 expressing oHSV, M002, and the human NK cell line, NK-92 MI. We assessed the cytotoxicity of NK cells against neuroblastoma with and without M002 infection, the effects of M002 on NK cell priming, and the impact of M002 and priming on the migratory capacity and CD107a expression of NK cells. To test clinical applicability, we then investigated the effects of M002 and NK cells on neuroblastoma in vivo. RESULTS: NK cells were more attracted to neuroblastoma cells that were infected with M002. There was an increase in neuroblastoma cell death with the combination treatment of M002 and NK cells both in vitro and in vivo. Priming the NK cells enhanced their cytotoxicity, migratory capacity and CD107a expression. CONCLUSIONS: To the best of our knowledge, these investigations are the first to demonstrate the effects of an oncolytic virus combined with self-maintaining NK cells in neuroblastoma and the priming effect of neuroblastoma on NK cells. The current studies provide a deeper understanding of the relation between NK cells and neuroblastoma and these data suggest that oHSV increases NK cell cytotoxicity towards neuroblastoma.

Herpes simplex encephalomyeloradiculitis initially presents with urinary retention.

Herpes simplex virus (HSV) infections necessitate careful management of urinary dysfunction and retention, which are underestimated conditions. Here, we present a rare case of HSV encephalomyeloradiculitis in a 76-year-old man, whose initial symptoms included urinary dysfunction and retention that alone lasted for approximately 1 week. Unlike in meningoencephalitis, high fever and headache were absent; however, the patient subsequently developed cauda equina syndrome and consciousness disturbance. Gadolinium-enhanced spinal MRI suggested enhanced cauda equina at the L2/3 level. Upon admission, he was treated for meningoencephalitis with acyclovir and steroid pulse therapy. Subsequent cerebrospinal fluid analysis result was positive for HSV DNA. A |brain MRI conducted 1 week after admission displayed high-intensity lesions in the white matter of the right temporal lobe, confirming HSV encephalomyeloradiculitis. These treatments were highly effective and gradually improved the patient's condition. He was discharged 1 month after hospitalization, and the urinary catheter was removed 2 weeks later. HSV infections can cause life-threatening encephalomyeloradiculitis. Therefore, both neurologists and urologists must pay attention to their occurrence and characteristics in clinical settings.

Acute generalised exanthematous pustulosis and herpes simplex virus: a case of possible overlap.

Acute generalised exanthematous pustulosis (AGEP) is a rare cutaneous disorder that presents with numerous non-follicular, pinpoint sterile pustules on a background of oedematous erythema that can coalesce, leading to desquamation. 90% of cases are triggered by medications, most often with antibiotics as the culprit. However, other triggers including viral infection have also been reported. Herpes simplex virus (HSV) as a viral trigger has not been previously explored. Here, we present a case of AGEP caused by bupropion, followed by a second presentation of assumed acute limited exanthematous pustulosis in the setting of disseminated HSV. This case may represent the first report of AGEP and HSV overlap. It also presents the interesting dilemma of differentiating AGEP and disseminated HSV (which can present similarly) as well as determining appropriate treatment and the utility versus risk of systemic steroid administration.

A review of HSV pathogenesis, vaccine development, and advanced applications.

Herpes simplex virus (HSV), an epidemic human pathogen threatening global public health, gains notoriety for its complex pathogenesis that encompasses lytic infection of mucosal cells, latent infection within neurons, and periodic reactivation. This intricate interplay, coupled with HSV's sophisticated immune evasion strategies, gives rise to various diseases, including genital lesions, neonatal encephalitis, and cancer. Despite more than 70 years of relentless research, an effective preventive or therapeutic vaccine against HSV has yet to emerge, primarily due to the limited understanding of virus-host interactions, which in turn impedes the identification of effective vaccine targets. However, HSV's unique pathological features, including its substantial genetic load capacity, high replicability, transmissibility, and neurotropism, render it a promising candidate for various applications, spanning oncolytic virotherapy, gene and immune therapies, and even as an imaging tracer in neuroscience. In this review, we comprehensively update recent breakthroughs in HSV pathogenesis and immune evasion, critically summarize the progress made in vaccine candidate development, and discuss the multifaceted applications of HSV as a biological tool. Importantly, we highlight both success and challenges, emphasizing the critical need for intensified research into HSV, with the aim of providing deeper insights that can not only advance HSV treatment strategies but also broaden its application horizons.

CFTR Inhibitors Display Antiviral Activity against Herpes Simplex Virus.

The cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-dependent Cl- channel, is closely associated with multiple pathogen infections, such as SARS-CoV-2. However, whether the function of the CFTR is involved in herpes simplex virus (HSV) infection has not been reported. To evaluate the association of CFTR activity with HSV infection, the antiviral effect of CFTR inhibitors in epithelial cells and HSV-infected mice was tested in this study. The data showed that treatment with CFTR inhibitors in different concentrations, Glyh-101 (5-20 µM), CFTRi-172 (5-20 µM) and IOWH-032 (5-20 µM), or the gene silence of the CFTR could suppress herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2) replication in human HaCaT keratinocytes cells, and that a CFTR inhibitor, Glyh-101 (10-20 µM), protected mice from HSV-1 and HSV-2 infection. Intracellular Cl- concentration ([Cl-]i) was decreased after HSV infection via the activation of adenylyl cyclase (AC)-cAMP signaling pathways. CFTR inhibitors (20 µM) increased the reduced [Cl-]i caused by HSV infection in host epithelial cells. Additionally, CFTR inhibitors reduced the activity and phosphorylation of SGK1 in infected cells and tissues (from the eye and vagina). Our study found that CFTR inhibitors can effectively suppress HSV-1 and HSV-2 infection, revealing a previously unknown role of CFTR inhibitors in HSV infection and suggesting new perspectives on the mechanisms governing HSV infection in host epithelial cells, as well as leading to potential novel treatments.

Herpes simplex virus in infancy: Evaluation of national surveillance case capture.

AIM: As herpes simplex virus (HSV) in infancy is not a mandatory notifiable condition in Australia, completeness of ascertainment by the Australian Paediatric Surveillance Unit (APSU) has been difficult to evaluate to date. We evaluated case capture in Queensland (QLD) and Western Australia (WA) using statewide laboratory and clinical data and complementary surveillance data collected via the APSU. METHODS: HSV polymerase chain reaction positive results in infants (0-3 months) from 2007 to 2017 were obtained from statewide public pathology providers in QLD and WA. Clinical data were extracted from patient records and compared to APSU reported cases. RESULTS: A total of 94 cases of HSV disease in infancy (70 QLD; 24 WA) were identified from laboratory data sets, compared to 36 cases (26 QLD; 10 WA) reported to the APSU. In total there was 102 unique cases identified; 28 cases were common to both data sets (seven skin eye mouth (SEM) disease, 13 central nervous system (CNS) disease and eight disseminated disease). Active surveillance captured 35% (36/102) of cases overall including 74% (14/19) of CNS, 71% (10/14) of disseminated and 17% (12/69) of SEM disease cases, respectively. Surveillance reported cases had a higher case-fatality rate compared to those not reported (14% vs. 3%, P = 0.038). Neurological sequelae at discharge were comparable between the groups. CONCLUSION: Active surveillance captures one third of hospitalised HSV cases in QLD and WA, including the majority with severe disease. However, morbidity and mortality remain high. Future studies on HSV will rely on observational studies. Enhanced case ascertainment through combined laboratory and surveillance data is essential for better understanding and improving outcomes.

Management of Refractory/Resistant Herpes Simplex Virus Infections in Haematopoietic Stem Cell Transplantation Recipients: A Literature Review.

Herpes simplex virus (HSV) infections in allogeneic haematopoietic stem cell transplantation (HSCT) recipients pose significant challenges, with higher incidence, severity, and risk of emergence of resistance to antivirals due to impaired T-cell mediated immunity. This literature review focuses on acyclovir-refractory/resistant HSV infections in HSCT recipients. The review addresses the efficacy of antiviral prophylaxis, the incidence of acyclovir-refractory/resistant HSV infections, and the identification of risk factors and potential prognostic impact associated with those infections. Additionally, alternative therapeutic options are discussed. While acyclovir prophylaxis demonstrates a significant benefit in reducing HSV infections in HSCT recipients and, in some cases, overall mortality, concerns arise about the emergence of drug-resistant HSV strains. Our systematic review reports a median incidence of acyclovir-resistant HSV infections of 16.1%, with an increasing trend in recent years. Despite limitations in available studies, potential risk factors of emergence of HSV resistance to acyclovir include human leucocyte antigen (HLA) mismatches, myeloid neoplasms and acute leukaemias, and graft-versus-host disease (GVHD). Limited evidences suggest a potentially poorer prognosis for allogeneic HSCT recipients with acyclovir-refractory/resistant HSV infection. Alternative therapeutic approaches, such as foscarnet, cidofovir, topical cidofovir, optimised acyclovir dosing, and helicase-primase inhibitors offer promising options but require further investigations. Overall, larger studies are needed to refine preventive and therapeutic strategies for acyclovir-refractory/resistant HSV infections in allogeneic HSCT recipients and to identify those at higher risk.

Latent toxoplasmosis, Cytomegalovirus, and Herpes Simplex Virus infections and risk of motorcycle accidents: A case-control study in a county with a high rate of motorcycle injuries in Iran.

BACKGROUND: Road traffic injuries (RTIs) are among the most important issues worldwide. Several studies reported that infection with the neurotropic parasite Toxoplasma gondii (T. gondii) increased the risk of car accidents. In this study, our objective was to investigate the possible associations among latent T. gondii, Cytomegalovirus (CMV), and Herpes Simplex Virus (HSV) infections with the risk of motorcycle accidents in Jahrom (Fars Province), which is a county with a high rate of motorcycle accidents in Iran. METHODS: In the setting of a case-control study; 176 motorcyclist men, including 88 survivors of motorcycle accidents and 88 motorcyclist without accidents, were considered as case and control groups, respectively. Rates of latent infections with T. gondii, CMV, and HSV were assessed by an enzyme-linked immunosorbent assay (ELISA). RESULTS: Eleven of 88 (12.5%) in the case group and 22 of 88 (25.0%) in controls were positive for anti-T. gondii IgG antibodies, this difference was statistically significant (OR = 0.42; CI: 0.19-0.95, p = 0.03). The general seroprevalence of CMV (94.3% in the case group vs. 87.5% in the control group, OR = 2.37; CI: 0.78-7.13, p = 0.12) and HSV (63.6% in the case group vs. 62.5% in the control group, OR = 1.05; CI: 0.57-1.94, p = 0.87) were not significantly different between the case and control groups. CONCLUSIONS: Although latent toxoplasmosis has been associated with traffic accidents in recent reports, we found a negative association between latent toxoplasmosis and motorcycle accidents among survivors of these accidents. As such, latent CMV and HSV infections did not differ significantly between the cases compared to the control groups.

Universal versus targeted treatment of neonatal herpes simplex virus among neonates presenting for sepsis evaluations.

PURPOSE OF REVIEW: The American Academy of Pediatrics recently published guidance for the evaluation and management of febrile infants. However, guidance on testing and empiric treatment for neonatal herpes simplex virus (HSV) remains less standardized and subject to clinical practice variation. RECENT FINDINGS: Recent reports reveal that high numbers of infants presenting for sepsis evaluations need to be treated empirically with acyclovir to capture one case of neonatal HSV. Clinical and laboratory risk factors for neonatal HSV identified in the literature can be used for a targeted approach to testing and treating infants for HSV to optimize resource utilization. SUMMARY: The literature supports a targeted approach to evaluation and empiric acyclovir treatment for neonatal HSV, but additional studies are needed to validate this approach given the rarity of disease.

Pulmonary herpes simplex virus and cytomegalovirus in patients with acute respiratory distress syndrome related to COVID-19.

PURPOSE: Human herpesviruses, particularly cytomegalovirus (CMV) and herpes simplex virus (HSV), frequently reactivate in critically ill patients, including those with acute respiratory distress syndrome (ARDS) related to coronavirus disease 2019 (COVID-19). The clinical interpretation of pulmonary herpesvirus reactivation is challenging and there is ongoing debate about its association with mortality and benefit of antiviral medication. We aimed to quantify the incidence and pathogenicity of pulmonary CMV and HSV reactivations in critically ill COVID-19 patients. METHODS: Mechanically ventilated COVID-19 patients seropositive for CMV or HSV were included in this observational cohort study. Diagnostic bronchoscopy with bronchoalveolar lavage was performed routinely and analyzed for alveolar viral loads and inflammatory biomarkers. Utilizing joint modeling, we explored the dynamic association between viral load trajectories over time and mortality. We explored alveolar inflammatory biomarker dynamics between reactivated and non-reactivated patients. RESULTS: Pulmonary reactivation (> 104 copies/ml) of CMV occurred in 6% of CMV-seropositive patients (9/156), and pulmonary reactivation of HSV in 37% of HSV-seropositive patients (63/172). HSV viral load dynamics prior to or without antiviral treatment were associated with increased 90-day mortality (hazard ratio [HR] 1.24, 95% confidence interval [CI] 1.04-1.47). The alveolar concentration of several inflammatory biomarkers increased with HSV reactivation, including interleukin (IL)-6, IL-1ß, granulocyte colony stimulating factor (G-CSF), and tumor necrosis factor (TNF). CONCLUSION: In mechanically ventilated COVID-19 patients, HSV reactivations are common, while CMV reactivations were rare. HSV viral load dynamics prior to or without antiviral treatment are associated with mortality. Alveolar inflammation is elevated after HSV reactivation.

Herpes simplex virus reactivation after nonablative fractional laser to treat facial photoaging.

Contemporary approaches for facial rejuvenation encompass the utilization of both ablative and nonablative laser techniques. Extensive research has elucidated the adverse consequences associated with ablative laser treatment, such as the emergence of infectious, follicular, scarring, and pigmentary alterations. Nonablative fractional lasers exhibit commendable cosmetic outcomes, characterized by a diminished incidence of complications owing to their photomechanical mechanisms, in contrast to ablative laser modalities. Nonetheless, it is imperative to acknowledge that untoward effects may still manifest. In this report, we present two cases of herpes simplex virus (HSV) reactivation subsequent to nonablative fractional resurfacing. Timely identification and the appropriate administration of antiviral agents are important, which serve as imperative measures to mitigate the long-term consequences that may arise in the event of complications.

Enhanced IL-12 transgene expression improves oncolytic viroimmunotherapy.

Introduction: Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas with unacceptably low cure rates occurring often in patients with neurofibromatosis 1 defects. To investigate oncolytic Herpes Simplex Virus (oHSV) as an immunotherapeutic approach, we compared viral replication, functional activity, and immune response between unarmed and interleukin 12 (IL-12)-armed oncolytic viruses in virus-permissive (B109) and -resistant (67C-4) murine MPNSTs. Methods: This study compared two attenuated IL-12-oHSVs with γ134.5 gene deletions (Δγ134.5) and the same transgene expression cassette. The primary difference in the IL-12-oHSVs was in their ability to counter the translational arrest response in infected cells. Unlike M002 (Δγ134.5, mIL-12), C002 (Δγ134.5, mIL-12, IRS1) expresses an HCMV IRS1 gene and evades dsRNA activated translational arrest in infected cells. Results and discussion: Our results show that oHSV replication and gene expression results in vitro were not predictive of oHSV direct oncolytic activity in vivo. Tumors that supported viral replication in cell culture studies resisted viral replication by both oHSVs and restricted M002 transgene expression in vivo. Furthermore, two IL-12-oHSVs with equivalent transcriptional activity differed in IL-12 protein production in vivo, and the differences in IL-12 protein levels were reflected in immune infiltrate activity changes as well as tumor growth suppression differences between the IL-12-oHSVs. C002-treated tumors exhibited sustained IL-12 production with improved dendritic cells, monocyte-macrophage activity (MHCII, CD80/CD86 upregulation) and a polyfunctional Th1-cell response in the tumor infiltrates. Conclusion: These results suggest that transgene protein production differences between oHSVs in vivo, in addition to replication differences, can impact OV-therapeutic activity.

Clinical characteristics and outcomes of patients with Herpes Simplex Encephalitis in Vietnam: a retrospective study.

BACKGROUND: Herpes simplex encephalitis (HSE) is an important central nervous infection with severe neurological sequelae. The aim of this study was to describe clinical characteristic and outcomes of patients with HSE in Vietnam. METHODS: This was a retrospective study of 66 patients with herpes simplex encephalitis who admitted to the National Hospital for Tropical Diseases, Hanoi, Vietnam from 2018 to 2021. The detection of herpes simplex virus (HSV) in cerebrospinal fluid was made by the real-time PCR assay. We reported the clinical manifestation on admission and evaluated clinical outcomes at the hospital discharge by modified Rankin Scale (mRS). Multivariate logistic regression analysis was used to analyze the independent risk factors of severe outcomes. RESULTS: Of the 66 patients with laboratory confirmed HSE, the median age was 53 years (IQR 38-60) and 44 patients (69.7%) were male. The most common manifestations included fever (100%), followed by the consciousness disorder (95.5%). Other neurological manifestation were seizures (36.4%), memory disorders (31.8%), language disorders (19.7%) and behavioral disorders (13.6%). Conventional magnetic resonance imaging (MRI) showed 93.8% patients with temporal lobe lesions, followed by abnormalities in insula (50%), frontal lobe (34.4%) and 48.4% of patients had bilateral lesions. At discharge, 19 patients (28.8%) completely recovered, 15 patients (22.7%) had mild sequelae, 28 patients (42.4%) had moderate to severe sequelae. Severe neurological sequelae were memory disorders (55.8%), movement disorders (53.5%), language disorders (30.2%). Multivariate logistic regression analysis showed that Glasgow score decrement at admission, seizures, and time duration from onset of symptoms to the start of Acyclovir treatment > 4 days were independent factors associated with severe outcomes in HSE patients. CONCLUSION: Glasgow score decrement, seizures and delay treatment with Acyclovir were associated with the poor outcome of patients with HSE.

m1A inhibition fuels oncolytic virus-elicited antitumor immunity via downregulating MYC/PD-L1 signaling.

N1-methyladenosine (m1A) RNA methylation is critical for regulating mRNA translation; however, its role in the development, progression, and immunotherapy response of head and neck squamous cell carcinoma (HNSCC) remains largely unknown. Using Tgfbr1 and Pten conditional knockout (2cKO) mice, we found the neoplastic transformation of oral mucosa was accompanied by increased m1A modification levels. Analysis of m1A-associated genes identified TRMT61A as a key m1A writer linked to cancer progression and poor prognosis. Mechanistically, TRMT61A-mediated tRNA-m1A modification promotes MYC protein synthesis, upregulating programmed death-ligand 1 (PD-L1) expression. Moreover, m1A modification levels were also elevated in tumors treated with oncolytic herpes simplex virus (oHSV), contributing to reactive PD-L1 upregulation. Therapeutic m1A inhibition sustained oHSV-induced antitumor immunity and reduced tumor growth, representing a promising strategy to alleviate resistance. These findings indicate that m1A inhibition can prevent immune escape after oHSV therapy by reducing PD-L1 expression, providing a mutually reinforcing combination immunotherapy approach.