Antiviral Research Articles

CNS Viral Infections-What to Consider for Improving Drug Treatment: A Plea for Using Mathematical Modeling Approaches.

Neurotropic viruses may cause meningitis, myelitis, encephalitis, or meningoencephalitis. These inflammatory conditions of the central nervous system (CNS) may have serious and devastating consequences if not treated adequately. In this review, we first summarize how neurotropic viruses can enter the CNS by (1) crossing the blood-brain barrier or blood-cerebrospinal fluid barrier; (2) invading the nose via the olfactory route; or (3) invading the peripheral nervous system. Neurotropic viruses may then enter the intracellular space of brain cells via endocytosis and/or membrane fusion. Antiviral drugs are currently used for different viral CNS infections, even though their use and dosing regimens within the CNS, with the exception of acyclovir, are minimally supported by clinical evidence. We therefore provide considerations to optimize drug treatment(s) for these neurotropic viruses. Antiviral drugs should cross the blood-brain barrier/blood cerebrospinal fluid barrier and pass the brain cellular membrane to inhibit these viruses inside the brain cells. Some antiviral drugs may also require intracellular conversion into their active metabolite(s). This illustrates the need to better understand these mechanisms because these processes dictate drug exposure within the CNS that ultimately determine the success of antiviral drugs for CNS infections. Finally, we discuss mathematical model-based approaches for optimizing antiviral treatments. Thereby emphasizing the potential of CNS physiologically based pharmacokinetic models because direct measurement of brain intracellular exposure in living humans faces ethical restrictions. Existing physiologically based pharmacokinetic models combined with in vitro pharmacokinetic/pharmacodynamic information can be used to predict drug exposure and evaluate efficacy of antiviral drugs within the CNS, to ultimately optimize the treatments of CNS viral infections.

Effect of Melatonin on Herpesvirus Type 1 Replication.

Acute HSV-1 infection is associated with mild symptoms, such as fever and lesions of the mouth, face and skin. This phase is followed by a latency period before reactivation, which is associated with symptoms ranging from ulcers to encephalitis. Despite available anti-HSV-1 drugs, the development of new antiviral agents is sought due to the presence of resistant viruses. Melatonin, a molecule secreted by the pineal gland, has been shown to be an antioxidant, inducer of antioxidant enzymes, and regulator of various biological processes. Clinical trials have explored its therapeutic utility in conditions including infections. This study focuses on melatonin's role in HSV-1 replication and the underlying mechanisms. Melatonin was found to decrease the synthesis of HSV-1 proteins in infected Vero cells measured by immunofluorescence, indicating an inhibition of HSV-1 replication. Additionally, it regulates the activities of antioxidant enzymes and affects proteasome activity. Melatonin activates the unfolded protein response (UPR) and autophagy and suppresses apoptosis in HSV-1-infected cells. In summary, melatonin demonstrates an inhibitory role in HSV-1 replication by modulating various cellular responses, suggesting its potential utility in the treatment of viral infections.

SARS-CoV-2 Mpro oligomerization as a potential target for therapy

The main protease (Mpro) of SARS-CoV-2 is critical in the virus's replication cycle, facilitating the maturation of polyproteins into functional units. Due to its conservation across taxa, Mpro is a promising target for broad-spectrum antiviral drugs. Targeting Mpro with small molecule inhibitors, such as nirmatrelvir combined with ritonavir (Paxlovid™), which the FDA has approved for post-exposure treatment and prophylaxis, can effectively interrupt the replication process of the virus. A key aspect of Mpro's function is its ability to form a functional dimer. However, the mechanics of dimerization and its influence on proteolytic activity remain less understood. In this study, we utilized biochemical, structural, and molecular modelling approaches to explore Mpro dimerization. We evaluated critical residues, specifically Arg4 and Arg298, that are essential for dimerization. Our results show that changes in the oligomerization state of Mpro directly affect its enzymatic activity and dimerization propensity. We discovered a synergistic relationship influencing dimer formation, involving both intra- and intermolecular interactions. These findings highlight the potential for developing allosteric inhibitors targeting Mpro, offering promising new directions for therapeutic strategies.

Chronic Hepatitis B in Women of Childbearing Age and Pregnant Women in China: A Cross-Sectional Study.

Pregnant women and women of childbearing age were enrolled in our study and their knowledge about the Hepatitis B virus (HBV) and chronic hepatitis B (CHB) was evaluated. A questionnaire was distributed to every woman in the cross-sectional study. The questionnaire was answered by all participants before they received health education and advice about HBV and CHB from the doctors visited. Data collected from all answers were analyzed using the χ2 test and logistic regression models. A total of 206 pregnant women and women of childbearing age with CHB infection were enrolled in the study during their first visit to the Infectious Diseases Clinic of the Third Affiliated Hospital of Guangzhou Medical University. Some women of childbearing age (40.8%) and pregnant women with CHB infection (30.6%) still believed HBV could be transmitted through diet and/or mosquito bites. Some women of childbearing age and pregnant women with CHB infection had limited knowledge of the prevention of HBV transmission (111 of 206, 53.9%). Women with higher levels of education had more knowledge about HBV (senior middle school, P = 0.02; university, P <0.01). The majority of participants were willing to take antiviral medicine to decrease the mother-to-child transmission (MTCT) rate of HBV. Some women of childbearing age and/or pregnant women with CHB infection have relatively limited knowledge about HBV or CHB. This situation contributes to the timeliness, or lack thereof, of these women with CHB to see a doctor and receive antiviral therapy. As a result, the morbidity and mortality of HBV-related complications could increase along with the rate of MTCT of HBV.

Biophysics-Guided Lead Discovery of HBV Capsid Assembly Modifiers.

Hepatitis B virus (HBV) is the leading cause of chronic liver pathologies worldwide. HBV nucleocapsid, a key structural component, is formed through the self-assembly of the capsid protein units. Therefore, interfering with the self-assembly process is a promising approach for the development of novel antiviral agents. Applied to HBV, this approach has led to several classes of capsid assembly modulators (CAMs). Here, we report structurally novel CAMs with moderate activity and low toxicity, discovered through a biophysics-guided approach combining docking, molecular dynamics simulations, and a series of assays with a particular emphasis on biophysical experiments. Several of the identified compounds induce the formation of aberrant capsids and inhibit HBV DNA replication in vitro, suggesting that they possess modest capsid assembly modulation effects. The synergistic computational and experimental approaches provided key insights that facilitated the identification of compounds with promising activities. The discovery of preclinical CAMs presents opportunities for subsequent optimization efforts, thereby opening new avenues for HBV inhibition.

Promising Potential of Curcumin and Related Compounds for Antiviral Drug Discovery.

Viruses are acellular, microscopic, and mobile particles containing genetic particles, either DNA/RNA strands as nucleoproteins, responsible for 69,53,743 deaths till the year 2023. Curcumin and related compounds are among the areas of pivotal interest for researchers because of their versatile pharmacological profile. Chemically known as diferuloylmethane, which is a main constituent of turmeric along with demethoxycurcumin and bisdemethoxycurcumin, they have a broad spectrum of antiviral activity against viruses such as human immunodeficiency virus, herpes simplex virus, influenza virus (Avian influenza) and Hepatitis C virus HIV. The possible role of curcumin as an antiviral agent may be attributed to the activation of the 20S proteasome, a cellular machinery responsible for degrading unfolded or misfolded proteins in a ubiquitin-independent manner. It shows suppression of HBV entry at various infection stages by inhibiting cccDNA replication by inhibiting the Wnt/β-catenin signaling pathway to attenuate IAV-induced myocarditis.

Integration of metalloproteome and immunoproteome reveals a tight link of iron-related proteins with COVID-19 pathogenesis and immunity

Increasing clinical data show that the imbalance of host metallome is closely associated with different kinds of disease, however, the intrinsic mechanisms of action of metals in immunity and pathogenesis of disease remain largely undefined. There is lack of multiplexed profiling system to integrate the metalloproteome-immunoproteome information at systemic level for exploring the roles of metals in immunity and disease pathogenesis. In this study, we build up a metal-coding assisted multiplexed proteome assay platform for serum metalloproteomic and immunoproteomic profiling. By taking COVID-19 as a showcase, we unbiasedly uncovered the most evident modulation of iron-related proteins, i.e., Ft and Tf, in serum of severe COVID-19 patients, and the value of Ft/Tf could work as a robust biomarker for COVID-19 severity stratification, which overtakes the well-established clinical risk factors (cytokines). We further uncovered a tight association of transferrin with inflammation mediator IL-10 in COVID-19 patients, which was proved to be mainly governed by the monocyte/macrophage of liver, shedding light on new pathophysiological and immune regulatory mechanisms of COVID-19 disease. We finally validated the beneficial effects of iron chelators as anti-viral agents in SARS-CoV-2-infected K18-hACE2 mice through modulation of iron dyshomeostasis and alleviating inflammation response. Our findings highlight the critical role of liver-mediated iron dysregulation in COVID-19 disease severity, providing solid evidence on the involvement of iron-related proteins in COVID-19 pathophysiology and immunity.

Using a Drug Repurposing Strategy to Virtually Screen Potential HIV-1 Entry Inhibitors That Block the NHR Domain of the Viral Envelope Protein gp41

Using a drug repurposing strategy, virtual screening of potential inhibitors of the NHR domain of the HIV-1 gp41 protein, a conserved region critical for the virus-cell membrane fusion and viral infectivity, was carried out. The used computational approach included: (1) molecular docking of this functionally significant region of the HIV-1 envelope with compounds from a library of bioactive molecules containing clinically approved drugs, experimental drugs, and investigational drug candidates; (2) assessing the binding affinity of these compounds to the therapeutic target; (3) molecular dynamics simulations of ligand/NHR-gp41 complexes; (4) calculations of the binding free energy followed by the analysis of molecular dynamics trajectories and selection of compounds promising to test for anti-HIV-1 activity. As a result, six compounds that exhibited the high binding affinity to the NHR domain of the HIV-1 gp41 protein and showed acceptable pharmacological properties were identified. The predicted compounds are assumed to form a promising basis for the development of new, effective and safe broad-spectrum antiviral agents able to inhibit the HIV-1 entry into the host cell.

Nanoformulation of the Broad-Spectrum Hydrophobic Antiviral Vacuolar ATPase Inhibitor Diphyllin in Human Recombinant H-ferritin.

As highlighted by recent pandemic outbreaks, antiviral drugs are crucial resources in the global battle against viral diseases. Unfortunately, most antiviral drugs are characterized by a plethora of side effects and low efficiency/poor bioavailability owing to their insolubility. This also applies to the arylnaphthalide lignin family member, diphyllin (Diph). Diph acts as a vacuolar ATPase inhibitor and has been previously identified as a promising candidate with broad-spectrum antiviral activity. However, its physicochemical properties preclude its efficient administration in vivo, complicating preclinical testing. We produced human recombinant H- ferritin (HsaFtH) and used it as a delivery vehicle for Diph encapsulation through pH-mediated reversible reassembly of HsaFtH. Diph nanoformulation was subsequently thoroughly characterized and tested for its non-target cytotoxicity and antiviral efficiency using a panel of pathogenic viral strain. We revealed that loading into HsaFtH decreased the undesired cytotoxicity of Diph in mammalian host cells. We also confirmed that encapsulated Diph exhibited slightly lower antiviral activity than free Diph, which may be due to the differential uptake mechanism and kinetics of free Diph and Diph@HsaFtH. Furthermore, we confirmed that the antiviral effect was mediated solely by Diph with no contribution from HsaFtH. It was confirmed that HsaFtH is a suitable vehicle that allows easy loading of Diph and production of highly homogeneous nanoparticles dispersion with promising broad-spectrum antiviral activity.

Monitoring the sensitivity of influenza viruses to oseltamivir, in Romania, from 2016 to 2023

Abstract Introduction: influenza is an acute viral disease caused by infection of the upper respiratory tract - difficult to control, which affects a large part of the population. Neuraminidase inhibitors (NAIs), such as oseltamivir and zanamivir, are the antiviral drugs utilized in Romania for the treatment of respiratory infections caused by the influenza viruses. The objective of the study is to monitor and analyze influenza viruses circulating in Romania, in terms of their susceptibility to oseltamivir, with the aim of signalling the emergence of viral strains resistant to antivirals. Methods: The phenotypic method was performed to evaluate the inhibitory effect of oseltamivir on the neuraminidase enzyme activity of influenza viruses. Genotypic methods (SNP-based assays or sequencing of neuraminidase/whole genome) were used for detecting amino acid substitutions associated with influenza antiviral resistance. The study period is from 2016 to 2023. Results: from the total number of influenza viruses isolated during the period (833 isolated), 670 strains were characterized antigenically and genetically, and the phenotypic susceptibility to antivirals was performed for 245 isolated viral strains. According to WHO criteria categories antiviral susceptibility based on IC50 data, none of the test results indicated reduced or highly reduced inhibition by oseltamivir. Conclusion: This monitoring, carried out in the National Influenza Center Romania - Cantacuzino NMMIRD, is extremely important to maintain effective flu control and further development of other antiviral agents.

Temporal changes in SARS-CoV-2 clearance kinetics and the optimal design of antiviral pharmacodynamic studies: an individual patient data meta-analysis of a randomised, controlled, adaptive platform study (PLATCOV)

Effective antiviral drugs prevent hospitalisation and death from COVID-19. Antiviral efficacy can be efficiently assessed in vivo by measuring rates of SARS-CoV-2 clearance estimated from serial viral genome densities quantitated in nasopharyngeal or oropharyngeal swab eluates. We conducted an individual patient data meta-analysis of unblinded arms in the PLATCOV platform trial to characterise changes in viral clearance kinetics and infer optimal design and interpretation of antiviral pharmacometric evaluations. Serial viral density data were analysed from symptomatic, previously healthy, adult patients (within 4 days of symptom onset) enrolled in a large multicentre, randomised, adaptive, pharmacodynamic, platform trial (PLATCOV) comparing antiviral interventions for SARS-CoV-2. Viral clearance rates over 1 week were estimated under a hierarchical Bayesian linear model with B-splines used to characterise temporal changes in enrolment viral densities and clearance rates. Bootstrap re-sampling was used to assess the optimal duration of follow-up for pharmacometric assessment, where optimal was defined as maximising the expected Z score when comparing effective antivirals with no treatment. PLATCOV is registered at ClinicalTrials.gov, NCT05041907. Between Sept 29, 2021, and Oct 20, 2023, 1262 patients were randomly assigned in the PLATCOV trial. Unblinded data were available from 800 patients (who provided 16 818 oropharyngeal viral quantitative PCR [qPCR] measurements), of whom 504 (63%) were female. 783 (98%) patients had received at least one vaccine dose and 703 (88%) were fully vaccinated. SARS-CoV-2 viral clearance was biphasic (bi-exponential). The first phase (α) was accelerated by effective interventions. For all the effective interventions studied, maximum discriminative power (maximum expected Z score) was obtained when evaluating serial data from the first 5 days after enrolment. Over the 2-year period studied, median viral clearance half-lives estimated over 7 days shortened from 16·6 h (IQR 15·3 to 18·2) in September, 2021, to 9·2 h (8·0 to 10·6) in October, 2023, in patients receiving no antiviral drugs, equivalent to a relative reduction of 44% (95% credible interval [CrI] 19 to 64). A parallel reduction in viral clearance half-lives over time was observed in patients receiving antiviral drugs. For example, in the 158 patients assigned to ritonavir-boosted nirmatrelvir (3380 qPCR measurements), the median viral clearance half-life reduced from 6·4 h (IQR 5·7 to 7·3) in June, 2022, to 4·8 h (4·2 to 5·5) in October, 2023, a relative reduction of 26% (95% CrI -4 to 42). SARS-CoV-2 viral clearance kinetics in symptomatic, vaccinated individuals accelerated substantially over 2 years of the pandemic, necessitating a change to how new SARS-CoV-2 antivirals are compared (ie, shortening the period of pharmacodynamic assessment). As of writing (October, 2023), antiviral efficacy in COVID-19 can be efficiently assessed in vivo using serial qPCRs from duplicate oropharyngeal swab eluates taken daily for 5 days after drug administration. Wellcome Trust.

Current Status of Potential Antiviral Drugs Derived from Plant, Marine, and Microbial Sources

Abstract: Natural substances have been the principal source of medications since antiquity. Natural goods are gaining popularity as a source of novel medications. This article investigates a variety of variables like plant, marine, and microbial sources that contribute to the growing interest in natural goods as a source of novel medications. Viruses have remained resistant to treatment and prevention for a longer period than other forms of life. Viral diseases can currently only be treated with a limited number of drugs. Significant research initiatives have been committed to identifying novel antiviral natural compounds to fight viruses that harm people, plants, insects, animals, fungi, and microbes. A recent study of the prevalence and sources of antiviral medications licensed by the Food and Drug Administration (FDA) has focused on natural products. Out of the estimated 250,000 higher plant species, only 5 to 15 percent have been thoroughly evaluated for the existence of bioactive substances in them, and the ability of the other species has hardly been investigated. This review aims to offer an overview of the crucial role played by natural products in the discovery and development of novel antiviral drugs with potent antiviral activity, including phytochemicals such as carbohydrates, coumarins, flavonoids, chromones, alkaloids, lignans, phenols, tannins, proteins, peptides, antiviral plant extracts, other marine, and microbial sources.

Fabrication and evaluation of ribavirin-loaded electrospun nanofibers as an antimicrobial wound dressing

BackgroundSkin is regarded as an essential first line of defense against harmful pathogens and it hosts an ecosystem of microorganisms that create a widely diverse skin microbiome. In chronic wounds, alterations in the host-microbe interactions occur forming polymicrobial biofilms that hinder the process of wound healing. Ribavirin, an antiviral drug, possesses antimicrobial activity, especially against Pseudomonas aeruginosa and Candida albicans, which are known as the main opportunistic pathogens in chronic wounds. RationaleIn this study, electrospun nanofiber systems loaded with ribavirin were developed as a potential wound dressing for topical application in chronic wounds. Ribavirin was chosen in this study owing to the emerging cases of antimicrobial (antibiotics and antifungal) resistance and the low attempts to discover new antimicrobial agents, which encouraged the repurposing use of current medication as an alternative solution in case of resistance to the available agents. Additionally, the unique mechanism of action of ribavirin, i.e., perturbing the bacterial virulence system without killing or stopping their growth and rendering the pathogens disarmed, might be a promising choice to prevent drug resistance. Cyclodextrin (CD) was utilized to formulate ribavirin as an electrospun nanofibers delivery system to enhance the absorption and accelerate the release of ribavirin for topical use. ResultsThe results demonstrated a successful ribavirin nanofibers fabrication that lacked beads and pores on the nanofibrous surfaces. Ribavirin underwent a physical transformation from crystalline to amorphous form, as confirmed by X-ray diffraction analysis. This change occurred due to the molecular dispersion after the electrospinning process. Additionally, the CD enhanced the encapsulation efficiency of ribavirin in the nanofibers as observed from the drug-loading results. Polyvinylpyrrolidone (PVP) and CD increased ribavirin released into the solution and the disintegration of fibrous mats which shrank and eventually dissolved into a gel-like substance as the ribavirin-loaded fibers began to break down from their border toward the midpoint. Cytotoxicity of ribavirin and CD was evaluated against human dermal fibroblasts (HFF-1) and the results showed a relatively safe profile of ribavirin upon 24-hour cell exposure, while CD was safe within 24- and 48-hour. ConclusionThis study provides valuable insights into the potential application of our nanofibrous system for treating chronic wounds; however, further antimicrobial and in-vivo studies are required to confirm its safety and effectiveness.

A Review of Pharmacotherapeutic Potentials of Black seeds (Nigella sativa) in the Management of Monkeypox Infection

Abstract: Around 3500 laboratory-confirmed cases of monkeypox infection, from 42 non-endemic countries have been reported to World Health Organization (WHO), during the current multicountry monkeypox outbreak. As of now, patients with monkeypox infection are managed symptomatically with supportive care. Hence, our current review focuses on the analysis of the pharmacotherapeutic potentials of black seeds (N. sativa). The literature was searched in web-based databases including web of science, Medline/PMC/PubMed, Embase, EBSCO, Google Scholar, Science Direct, and reference lists to identify relevant publications. Several clinical, animal, in-vivo, in-vitro, and in-silico studies have confirmed the antiviral efficacy of N. sativa against various viruses. In addition, previous research have demonstrated the analgesic, anti-inflammatory, antibacterial, antioxidant, and immunomodulatory effects of Black seeds (N. sativa), which would help to alleviate the signs, symptoms, and complications associated with monkeypox infection. In consequence, black seeds (N. sativa) could be added as an adjuvant therapy along with repurposed/ investigational antiviral drugs and supportive care in the management of patients with monkeypox infection in early stages to prevent inflammatory conditions and secondary bacterial infections. The safety and efficacy of Black seeds (N. sativa) in the management of monkeypox infection would further be established by future randomized controlled clinical trials.

Click chemistry can access unnatural N-acetylneuraminic acid–anchored β-cyclodextrin conjugates as potential anti-SARS-CoV-2 entry inhibitors

Multivalent N-acetylneuraminic acid (Neu5Ac) derivatives can be used to block virus entry into host cells by mimicking the natural receptors of the virus. However, the antiviral properties of unnatural Neu5Ac derivatives have not been extensively studied. Our study presents a facile and robust strategy for anchoring multiple unnatural Neu5Ac at the primary face of the β-cyclodextrin (β-CD) core using click chemistry. Further, we evaluated the antiviral activity of these conjugates and found that the monovalent and heptavalent unnatural Neu5Ac conjugates exhibited different antiviral activity against SARS-CoV-2 spike pseudovirus in hACE2-overexpressing BHK-21 cells without significant cytotoxicity (CC50 > 100 µM). The most potent inhibition was observed for conjugate 9c, with the half-maximal inhibitory concentration of 24.78 µM. The surface plasmon resonance study was also performed directly to elucidate the binding affinity of conjugate 9c to three CoVs spike proteins. The overall results suggest that the coupling of multiple unnatural Neu5Ac to the C6 carbons of β-CD with suitable linkage can bind the spike protein, thus blocking the entry of CoVs into host cells, implying that multivalent unnatural Neu5Ac derivatives are promising antiviral entry agents.

Arohynapene A Produced by &lt;i&gt;Penicillium steckii&lt;/i&gt; JB-NW-2-1 Isolated from &lt;i&gt;Avicennia marina&lt;/i&gt; (Forssk.) Vierh and Its Cytotoxic Activities

Mangrove-associated endophytic fungi are producers of secondary metabolites in unique and diverse structures with interesting biological activities such as antiviral, antifungal, antibacterial, anti-inflammatory, and cytotoxic agents. Endophytes play an important role in the physiological activities of the host plants, influencing the improvement of resistance to stress, insects, nematodes, and diseases. In this study, arohynapene A, a polyketide compound, was successfully isolated from the mangrove-derived fungus Penicillium steckii JB-NW-2-1 obtained from mangrove plant Avicennia marina (Forssk) Vierh. The structure was determined by a spectroscopic method including IR, MS, 1D-, and 2D-NMR techniques. This compound was evaluated for cytotoxic activities using resazurin assay against four cancer cells, HeLa cervical, MCF-7 breast cancer, B16-F10 melanoma, and A549 lung adenocarcinoma. The results showed no significant activities against all cancer cells tested (IC50 &gt; 500 µM).

Recent Trends on Synthesis of Benzimidazoles

Abstract: Preparation of benzimidazole derivatives have become the interest of many chemists because of the versatile therapeutic activity of benzimidazoles as antiulcer, antimicrobial, anti-viral, anticancer, anti-inflammatory, analgesic and anthelmintic drugs. This review will de-scribe the most recent research on benzimidazole synthesis.

Proofreading exonuclease activity of replicative polymerase epsilon promotes cellular tolerance to arabinosides in CTF18-dependent and -independent manner

Ara-A, Ara-C, Ara-G, and Ara-T are arabinose sugars combined with adenine, cytosine, guanine, and thymine bases, respectively. These drugs are clinically important as these drugs are commonly used as anti-viral and anti-cancer drugs. Ara-C, an arabinoside, serves as a chain terminator of deoxyribonucleic acid (DNA) replication by interfering with replication after it is incorporated at the 3′ end of nascent DNA, thereby restricting the proliferation of viruses and cancer cells. The incorporated Ara-CMP is efficiently removed by the proofreading exonuclease activity of polymerase epsilon (Polε), in which the alternative clamp loader CTF18 plays a pivotal role. However, the requirement of CTF18 for the removal of the other arabinosides from the 3′ end of nascent DNA remains unclear. Here, we explored DNA repair pathways responsible for the cellular tolerance to Ara-A and found that cells deficient in the proofreading exonuclease activity of Polε (POLE1exo−/−) showed the highest sensitivity to Ara-A. This activity was also required for cellular tolerance to Ara-G and Ara-T. CTF18−/− cells showed higher Ara-A sensitivity than wild-type cells, though it was critically lower than that of POLE1exo−/− cells. Similar trends were observed for the sensitivity to Ara-G and Ara-T. These results indicate that these arabinosides are removed by Polε proofreading exonuclease activity, and CTF18 is pivotal for Polε-mediated Ara-C removal but does not play critical roles for Polε-mediated removal of Ara-A, Ara-G, and Ara-T. In this study, we unveiled a difference between Ara-C and the other arabinosides (Ara-A, Ara-G, and Ara-T) in the removal from the 3′ end of nascent DNA.

Hepatitis C virus-related autoimmunity before and after viral clearance: a single center, prospective, observational study.

Hepatitis C virus (HCV) chronic infection is frequently associated to autoimmune manifestations. The aim of this study was to prospectively evaluate the occurrence of clinical and/or laboratory features of autoimmunity in a cohort of 140 consecutive HCV chronically infected patients treated with direct-acting antiviral agents (DAAs) and followed-up for 96 weeks. All patients were screened for cryoglobulins, rheumatoid factor (RF), C3, C4, antinuclear antibody (ANA), anti-smooth muscle (ASMA), anti-liver kidney microsome type 1 (anti-LKM1), anti-mitochondrial antibodies (AMA), anti-neutrophil cytoplasmic antibodies (ANCA), and anti-liver cytosol type 1/soluble liver antigen (anti-LC1/SLA) autoantibodies before therapy and 12, 48 and 96 weeks after treatment. They were then grouped according to the expression of laboratory findings and related autoimmune diseases. At baseline, autoimmune manifestations were found in 70 patients: 83% of them were cryoglobulinemic, whereas ANA, AMA, perinuclear ANCA (pANCA) and LKM/LC1 autoantibodies were found in the remaining 17%. An autoimmune disease was diagnosed in 9 cases, two of them featuring an autoimmune liver disease (AILD). At the end of follow-up, despite viral clearance and regression of vasculitis, cryoglobulins persisted in 12 patients (21%), and autoantibodies disappeared or decreased in most of cases but, with the exception of the 2 patients diagnosed as AILD, associated autoimmune diseases remained stable. In one patient with relapsing cryoglobulinemia and ANA positivity, type-1 autoimmune hepatitis was defined. Conversely, autoantibodies first appeared after viral clearance in 5 patients, of whom one was diagnosed with type-1 autoimmune hepatitis and one with pANCA+ primary sclerosing cholangitis. Following DAA-induced viral clearance, cryoglobulins may persist or reappear. Autoantibodies changed dynamically in step with the disappearance of a previously diagnosed or the occurrence of a new AILD. A longer follow-up will be necessary to establish the possible diagnosis of a newly onset AILD, the reactivation of cryoglobulinemic vasculitis and even its progression to non-Hodgkin lymphoma.

Bell's palsy in a seven-month-old twin infant: a case report

Idiopathic peripheral facial paralysis is a rare condition in the pediatric population under one year of age, characterized by paralysis of the structures innervated by the facial nerve. This report describes the first infant in Brazil to be diagnosed with this clinical condition. A 7-months-old twin infant presented with altered left oromotor control and a discrete incomplete closure of the left eyelid when blinking, although with normal tear production. Her primitive reflexes were present and the spontaneous movements of the four limbs were normal. An investigation for infectious etiology and a magnetic resonance imaging of the brain were performed and did not show any alterations. Thus, the diagnosis of Bell's palsy was assumed, and oral prednisone was prescribed for five days. The patient evolved with total resolution of the facial paralysis during the first two weeks after discharge. Most cases of peripheral facial paralysis in children are idiopathic, while the others are associated with infectious and/or traumatic etiologies. There are still no consistent data proving the benefit of the use of corticoid alone or in combination with antiviral drugs for the treatment of children under one year of age.