Adenovirus infection and disease in recipients of hematopoietic cell transplantation

Translational selenium nanoparticles boost GPx1 activation to reverse HAdV-14 virus-induced oxidative damage

Human adenovirus (HAdV) can cause severe respiratory infections in immunocompromised patients, but its clinical treatment is seriously limited by side effects of drugs such as poor efficacy, low bioavailability and severe nephrotoxicity. Trace element selenium (Se) has been found will affect the disease progression of pneumonia, but its antivirus efficacy could be improved by speciation optimization. Therefore, herein we performed anti-HAdV effects of different Se speciation and found that lentinan (LNT)-decorated selenium nanoparticles (SeNPs) exhibited low cytotoxicity and excellent anti-HAdV antiviral activity. Furthermore, SeNPs@LNT reduced the HAdV infection-induced mitochondrial damage and excessive production of reactive oxygen species (ROS). It was also involved in the repair of host cell DNA damage and inhibition of viral DNA replication. SeNPs@LNT inhibited HAdV-induced apoptosis mainly by modulating the p53/Bcl-2 apoptosis signaling pathway. In vivo, SeNPs@LNT replenished Se by targeting the infected site through the circulatory system and was involved in the synthesis of Glutathione peroxidase 1 (GPx1). More importantly, GPx1 played an antioxidant and immunomodulatory role in alleviating HAdV-induced inflammatory cytokine storm and alleviating adenovirus pneumonia in Se-deficient mice. Collectively, this study provides a Se speciation of SeNPs@LNT with anti-HAdV activity, and demonstrate that SeNPs@LNT is a promising pharmaceutical candidate for the treatment of HAdV.

Adenovirus infection in allogeneic hematopoietic cell transplantation

Adenovirus (AdV) infection occurs in 0-20% of patients in the first 3-4 months after allogeneic hematopoietic cell transplantation (HCT), being higher in pediatric than in adult patients. About 50% of AdV infections involve the blood, which in turn, correlates with an increased risk developing AdV diseases, end-organ damage, and 6-month overall mortality. The main risk factors for AdV infection are T-cell depletion of the graft by ex vivo selection procedures or in vivo use of alemtuzumab or antithymocyte serum, development of graft versus host disease (GVHD) grade III-IV, donor type (haploidentical or human leucocyte antigen mismatched related donor > cord blood> unrelated matched donor) and severe lymphopenia (<0.2 × 109 /L). The prevention of AdV disease relies on early diagnosis of increasing viral replication in blood or stool and the pre-emptive start of cidofovir as viral load exceeds the threshold of ≥102-3 copies/mL in blood and/or 106 copies/g stool in the stool. Cidofovir (CDV), a cytosine monophosphate nucleotide analog, is currently the only antiviral recommended for AdV infection despite limited efficacy and moderate risk of nephrotoxicity. Brincidofovir, a lipid derivative of CDV with more favorable pharmacokinetics properties and superior efficacy, is not available and currently is being investigated for other viral infections. The enhancement of virus-specific T-cell immunity in the first few months post-HCT by the administration of donor-derived or third-party-donor-derived virus-specific T-cells represents an innovative and promising modality of intervention and data of efficacy and safety of the ongoing prospective randomized studies are eagerly awaited.

Pediatric adenovirus pneumonia: clinical practice and current treatment

Adenovirus pneumonia is common in pediatric upper respiratory tract infection, which is comparatively easy to develop into severe cases and has a high mortality rate with many influential sequelae. As for pathogenesis, adenoviruses can directly damage target cells and activate the immune response to varying degrees. Early clinical recognition depends on patients' symptoms and laboratory tests, including those under 2 years old, dyspnea with systemic toxic symptoms, atelectasis or emphysema in CT image, decreased leukocytes, and significantly increased C-reaction protein (CRP) and procalcitonin (PCT), indicating the possibility of severe cases. Until now, there is no specific drug for adenovirus pneumonia, so in clinical practice, current treatment comprises antiviral drugs, respiratory support and bronchoscopy, immunomodulatory therapy, and blood purification. Additionally, post-infectious bronchiolitis obliterans (PIBO), hemophagocytic syndrome, and death should be carefully noted. Independent risk factors associated with the development of PIBO are invasive mechanical ventilation, intravenous steroid use, duration of fever, and male gender. Meanwhile, hypoxemia, hypercapnia, invasive mechanical ventilation, and low serum albumin levels are related to death. Among these, viral load and serological identification are not only "gold standard" for adenovirus pneumonia, but are also related to the severity and prognosis. Here, we discuss the progress of pathogenesis, early recognition, therapy, and risk factors for poor outcomes regarding severe pediatric adenovirus pneumonia.

Inhibition of HAdV-14 induced apoptosis by selenocystine through ROS-mediated PARP and p53 signaling pathways

BACKGROUND

Human Adenovirus (HAdV) can cause severe respiratory symptoms in people with low immunity and there is no targeted treatment for adenovirus infection. Anti-adenoviral drugs have high clinical significance for inhibiting adenovirus infection. Selenium (Se) plays an important role in anti-oxidation, redox signal transduction, and redox homeostasis. The excellent biological activity of Se is mainly achieved by being converted into selenocystine (SeC). Se participates in the active sites of various selenoproteins in the form of SeC. The ability of SeC to resist the virus has raised high awareness due to its unique antioxidative activity in recent years. The antiviral ability of the SeC was determined by detecting the infection rate of the virus in the cells.

METHODS

The experiment mainly investigated the antiviral mechanism of SeC by locating the virus in the cell, detecting the generation of ROS, observing the DNA status of the cell, and monitoring the mitochondrial membrane potential.

RESULTS

In the present study, SeC was designed to resist A549 cells infections caused by HAdV-14. SeC could prevent HAdV-14 from causing cell apoptosis-related to DNA damage. SeC significantly inhibited ROS generation and protect the cells from oxidative damage induced by ROS against HAdV-14. SeC induced the increase of antiviral cytokines such as IL-6 and IL-8 by activating the Jak2 signaling pathway, and repaired DNA lesions by suppressing ATR, p53, and PARP signaling pathways.

CONCLUSION

SeC might provide an effective selenium species with antiviral properties for the therapies against HAdV-14.

Adenoviruses in medicine: innocuous pathogen, predator, or partner

The consequences of human adenovirus (HAdV) infections are generally mild. However, despite the perception that HAdVs are harmless, infections can cause severe disease in certain individuals, including newborns, the immunocompromised, and those with pre-existing conditions, including respiratory or cardiac disease. In addition, HAdV outbreaks remain relatively common events and the recent emergence of more pathogenic genomic variants of various genotypes has been well documented. Coupled with evidence of zoonotic transmission, interspecies recombination, and the lack of approved AdV antivirals or widely available vaccines, HAdVs remain a threat to public health. At the same time, the detailed understanding of AdV biology garnered over nearly 7 decades of study has made this group of viruses a molecular workhorse for vaccine and gene therapy applications.

Adenovirus Infection and Transplantation

Adenoviruses result in a wide array of clinical presentations, including primarily respiratory, gastrointestinal, genitourinary, or systemic infections. Although adenovirus causes mild disease limited to a single organ system in immunocompetent individuals, severe and life-threatening infections do rarely occur. Disseminated disease and severe localized disease resulting in significant morbidity and mortality have been well described in the immunocompromised populations. Although asymptomatic viremia, respiratory tract, and gastrointestinal infections are the most common disease in most transplant patients, renal transplant patients more commonly experience urinary tract infections, including hemorrhagic cystitis or nephritis. Diagnosis requires astute clinical awareness of the patient's clinical presentation that would be compatible with adenovirus combined with cultures, molecular testing, polymerase chain reaction, and tissue sampling. There is no Food and Drug Administration-approved treatment for adenovirus; however, several studies have evaluated therapeutic options including cidofovir, brincidofovir, and immunotherapy. This article will summarize our current understanding of adenovirus in the transplant population.

Adenoviral Respiratory Infection-Associated Mortality in Children: A Retrospective Case Series

Viral respiratory infections are a leading cause of illness and hospitalization in young children worldwide. Case fatality rates in pediatric patients with adenoviral lower respiratory tract infection requiring intensive care unit (ICU) admission have been reported between 7 and 22%. We investigated the demographics and clinical characteristics in pediatric mortalities associated with adenoviral respiratory infection at 12 academic children's hospitals in the United States. There were 107 mortality cases included in our study, 73% of which had a chronic medical condition. The most common chronic medical condition was immunocompromised state in 37 cases (35%). The incidences of pediatric acute respiratory distress syndrome (78%) and multiple organ dysfunction syndrome (94%) were profound. Immunocompetent cases were more likely to receive mechanical ventilation within the first hour of ICU admission (60 vs. 14%, p < 0.001) and extracorporeal membrane oxygenation (27 vs. 5%, p = 0.009), and less likely to receive continuous renal replacement therapy (20 vs. 49%, p = 0.002) or have renal dysfunction (54 vs. 78%, p = 0.014) as compared with immunocompromised cases. Immunocompromised cases were more likely to have bacteremia (57 vs. 16%, p < 0.001) and adenoviremia (51 vs. 17%, p < 0.001) and be treated with antiviral medications (81 vs. 26%, p < 0.001). We observed a high burden of nonrespiratory organ system dysfunction in a cohort of pediatric case fatalities with adenoviral respiratory infection. The majority of cases had a chronic medical condition associated with an increased risk of complications from viral respiratory illness, most notably immunocompromised state. Important treatment differences were noted between immunocompromised and immunocompetent cases.

Evaluation of the Anti-Adenoviral Activity of ALTANT, an Ozonated Alcohol Disinfectant

Seven human mastadenovirus (HAdV) species (A-G) are known with more than 100 reported types. HAdV is highly resistant to common hand sanitizers. Epidemic keratoconjunctivitis and pharyngoconjunctival fever are caused by HAdV, which can be explosively transmitted in a confined space, resulting in outbreaks, such as nosocomial infections. Given the absence of an antiviral agent against the HAdV infection, it is important to prevent the spread of the infection by using disinfectants. Ozone has already been well-known for its bactericidal and virucidal effects. ALTANT is an ozonated alcohol preparation developed by E-TECH Co., Ltd. (Kobe, Hyogo, Japan). In this study, we mixed ALTANT with different HAdV types at a ratio of 9:1 and determined HAdV viability after instantaneous reactions for varying periods (flash to 5 minutes) using the TCID50 assay. The assay results demonstrated that the HAdV viability decreased by 1/10 to 1/100 within 1 minute after the reaction; additionally, slight differences in the reactivity were observed among the HAdV types. HAdV viability decreased by a factor of > 4log₁₀, and the virus was eliminated within 3 minutes. This study demonstrated the potent HAdV disinfection effect of ALTANT.

Isolation of a novel intertypic recombinant human mastadenovirus B2 from two unrelated bone marrow transplant recipients

Human adenoviruses (HAdV) are well-known opportunistic pathogens of immunocompromised adult and pediatric patients but specific associations between HAdV species or individual HAdV types and disease are poorly understood.

In this study we report the isolation of a novel HAdV-B2 genotype from two unrelated immunocompromised patients, both recipients of a hematopoietic cell transplant. In both patients, the course of HAdV infection is consistent with a scenario of reactivation of a latent virus rather than a primary opportunistic infection.

Archived HAdV PCR-positive plasma, urine, and stool specimens were processed for virus isolation and detailed molecular characterization. Virus isolates were recovered from patient 1 from PCR-positive urine specimens obtained at days 103 and 116 after transplant in association with gross hematuria, and from a stool specimen obtained 138 days after transplant in association with diarrhea. An isolate was recovered from patient 2 from a PCR-positive urine specimen. Hexon and fiber gene amplification and sequencing were carried out for initial molecular typing, identifying the isolates as an intertypic recombinant with a HAdV-11-like hexon gene and a HAdV-77-like fiber gene. Comprehensive restriction fragment length polymorphism (RFLP) analysis was performed on viral DNA purified from urine and stool isolates, and next generation whole genome sequencing was carried out on purified viral genomic DNA. The genomes of the two isolated strains are 99.5% identical and represent the same RFLP genomic variant. The identified virus is a novel HAdV-B2 genotype designated HAdV-78 exhibiting a HAdV-11-like penton base, a HAdV-11-like hexon and a HAdV-77-like fiber (P11H11F77).

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A novel HAdV-B2 type was isolated from 2 unrelated stem cell transplant recipients.

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The two isolated strains are 99.5% identical and represent the same genomic variant.

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The virus is an intertypic recombinant P11H11F77 designated HAdV-78.

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Genotype HAdV-78 is closely related to HAdV-77 with a 99% sequence similarity.