Adeno-associated virus 2 infection in children with non-A-E hepatitis.

An outbreak of acute hepatitis of unknown aetiology in children was reported in Scotland1 in April 2022 and has now been identified in 35 countries2. Several recent studies have suggested an association with human adenovirus with this outbreak, a virus not commonly associated with hepatitis. Here we report a detailed case-control investigation and find an association between adeno-associated virus 2 (AAV2) infection and host genetics in disease susceptibility. Using next-generation sequencing, PCR with reverse transcription, serology and in situ hybridization, we detected recent infection with AAV2 in plasma and liver samples in 26 out of 32 (81%) cases of hepatitis compared with 5 out of 74 (7%) of samples from unaffected individuals. Furthermore, AAV2 was detected within ballooned hepatocytes alongside a prominent T cell infiltrate in liver biopsy samples. In keeping with a CD4+ T-cell-mediated immune pathology, the human leukocyte antigen (HLA) class II HLA-DRB1*04:01 allele was identified in 25 out of 27 cases (93%) compared with a background frequency of 10 out of 64 (16%; P = 5.49 × 10-12). In summary, we report an outbreak of acute paediatric hepatitis associated with AAV2 infection (most likely acquired as a co-infection with human adenovirus that is usually required as a 'helper virus' to support AAV2 replication) and disease susceptibility related to HLA class II status.

Adeno-associated virus type 2 in US children with acute severe hepatitis.

As of August 2022, clusters of acute severe hepatitis of unknown aetiology in children have been reported from 35 countries, including the USA1,2. Previous studies have found human adenoviruses (HAdVs) in the blood from patients in Europe and the USA3-7, although it is unclear whether this virus is causative. Here we used PCR testing, viral enrichment-based sequencing and agnostic metagenomic sequencing to analyse samples from 16 HAdV-positive cases from 1 October 2021 to 22 May 2022, in parallel with 113 controls. In blood from 14 cases, adeno-associated virus type 2 (AAV2) sequences were detected in 93% (13 of 14), compared to 4 (3.5%) of 113 controls (P < 0.001) and to 0 of 30 patients with hepatitis of defined aetiology (P < 0.001). In controls, HAdV type 41 was detected in blood from 9 (39.1%) of the 23 patients with acute gastroenteritis (without hepatitis), including 8 of 9 patients with positive stool HAdV testing, but co-infection with AAV2 was observed in only 3 (13.0%) of these 23 patients versus 93% of cases (P < 0.001). Co-infections by Epstein-Barr virus, human herpesvirus 6 and/or enterovirus A71 were also detected in 12 (85.7%) of 14 cases, with higher herpesvirus detection in cases versus controls (P < 0.001). Our findings suggest that the severity of the disease is related to co-infections involving AAV2 and one or more helper viruses.

A Case Series of Children with Acute Hepatitis and Human Adenovirus Infection.

BACKGROUND: Human adenoviruses typically cause self-limited respiratory, gastrointestinal, and conjunctival infections in healthy children. In late 2021 and early 2022, several previously healthy children were identified with acute hepatitis and human adenovirus viremia. METHODS: We used International Classification of Diseases, 10th Revision, codes to identify all children (<18 years of age) with hepatitis who were admitted to Children's of Alabama hospital between October 1, 2021, and February 28, 2022; those with acute hepatitis who also tested positive for human adenovirus by whole-blood quantitative polymerase chain reaction (PCR) were included in our case series. Demographic, clinical, laboratory, and treatment data were obtained from medical records. Residual blood specimens were sent for diagnostic confirmation and human adenovirus typing. RESULTS: A total of 15 children were identified with acute hepatitis - 6 (40%) who had hepatitis with an identified cause and 9 (60%) who had hepatitis without a known cause. Eight (89%) of the patients with hepatitis of unknown cause tested positive for human adenovirus. These 8 patients plus 1 additional patient referred to this facility for follow-up were included in this case series (median age, 2 years 11 months; age range, 1 year 1 month to 6 years 5 months). Liver biopsies indicated mild-to-moderate active hepatitis in 6 children, some with and some without cholestasis, but did not show evidence of human adenovirus on immunohistochemical examination or electron microscopy. PCR testing of liver tissue for human adenovirus was positive in 3 children (50%). Sequencing of specimens from 5 children showed three distinct human adenovirus type 41 hexon variants. Two children underwent liver transplantation; all the others recovered with supportive care. CONCLUSIONS: Human adenovirus viremia was present in the majority of children with acute hepatitis of unknown cause admitted to Children's of Alabama from October 1, 2021, to February 28, 2022, but whether human adenovirus was causative remains unclear. Sequencing results suggest that if human adenovirus was causative, this was not an outbreak driven by a single strain. (Funded in part by the Centers for Disease Control and Prevention.).

Ex Vivo and In Vivo CD46 Receptor Utilization by Species D Human Adenovirus Serotype 26 (HAdV26).

Human adenovirus serotype 26 (Ad26) is used as a gene-based vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HIV-1. However, its primary receptor portfolio remains controversial, potentially including sialic acid, coxsackie and adenovirus receptor (CAR), integrins, and CD46. We and others have shown that Ad26 can use CD46, but these observations were questioned on the basis of the inability to cocrystallize Ad26 fiber with CD46. Recent work demonstrated that Ad26 binds CD46 with its hexon protein rather than its fiber. We examined the functional consequences of Ad26 for infection in vitro and in vivo. Ectopic expression of human CD46 on Chinese hamster ovary cells increased Ad26 infection significantly. Deletion of the complement control protein domain CCP1 or CCP2 or the serine-threonine-proline (STP) region of CD46 reduced infection. Comparing wild-type and sialic acid-deficient CHO cells, we show that the usage of CD46 is independent of its sialylation status. Ad26 transduction was increased in CD46 transgenic mice after intramuscular (i.m.) injection but not after intranasal (i.n.) administration. Ad26 transduction was 10-fold lower than Ad5 transduction after intratumoral (i.t.) injection of CD46-expressing tumors. Ad26 transduction of liver was 1,000-fold lower than that ofAd5 after intravenous (i.v.) injection. These data demonstrate the use of CD46 by Ad26 in certain situations but also show that the receptor has little consequence by other routes of administration. Finally, i.v. injection of high doses of Ad26 into CD46 mice induced release of liver enzymes into the bloodstream and reduced white blood cell counts but did not induce thrombocytopenia. This suggests that Ad26 virions do not induce direct clotting side effects seen during coronavirus disease 2019 (COVID-19) vaccination with this serotype of adenovirus. IMPORTANCE The human species D Ad26 is being investigated as a low-seroprevalence vector for oncolytic virotherapy and gene-based vaccination against HIV-1 and SARS-CoV-2. However, there is debate in the literature about its tropism and receptor utilization, which directly influence its efficiency for certain applications. This work was aimed at determining which receptor(s) this virus uses for infection and its role in virus biology, vaccine efficacy, and, importantly, vaccine safety.

Respiratory viruses and febrile response in children with febrile seizures: A cohort study and embedded case-control study.

OBJECTIVE: There are limited data on the pathogen-related and host-related factors in the pathogenesis of febrile seizures (FS). We designed a controlled study to compare the role of different respiratory viruses and febrile response in FS. METHODS: In a prospective cohort study of 1899 pediatric emergency room patients aged 6 months-6 years with a positive respiratory virus multiplex PCR, we identified 225 patients with FSs. We first compared the distribution of respiratory viruses in age-stratified patients with FSs with that in other patients. In an embedded case-control study, we compared the febrile response in patients with FSs with that in the controls matched for age, season and the same respiratory virus. RESULTS: The relative risk for FS was the highest for coronavirus OC43, 229E, and NL63 infections [RR: 3.2, 95 % confidence interval (CI): 1.4-7.2) and influenza A and B [RR: 2.5, 95 % CI: 1.4-4.7] as compared to those with other respiratory viral infections. The patients with FSs had a stronger febrile response of 39.2 °C (difference: 0.8 °C, 95 % CI: 0.5-1.2) later during hospitalization after acute care than the controls matched for the same respiratory virus. CONCLUSIONS: Influenza and coronaviruses caused relatively more FS-related emergency room visits than other respiratory viruses. Furthermore, the febrile response was stronger in the patients with FSs than in the controls matched for the same respiratory virus. The results suggest that the pathomechanism of FSs includes modifiable pathogen-related and host-related factors with possible potential in the prevention of FSs.

Adenovirus-Extracellular Protein Interactions and Their Impact on Innate Immune Responses by Human Mononuclear Phagocytes.

The aim of this review is to highlight how, in a syngeneic system, human mononuclear phagocytes respond to environments containing human adenovirus (HAdV) and soluble extracellular proteins that influence their innate immune response. Soluble extracellular proteins, including immunoglobulins, blood clotting factors, proteins of the complement system, and/or antimicrobial peptides (AMPs) can exert direct effects by binding to a virus capsid that modifies interactions with pattern recognition receptors and downstream signaling. In addition, the presence, generation, or secretion of extracellular proteins can indirectly influence the response to HAdVs via the activation and recruitment of cells at the site of infection.

The clinical impact of PCR-based point-of-care diagnostic in respiratory tract infections in children.

BACKGROUND: Children are commonly affected by respiratory tract infections. Based on clinical symptoms, laboratory evaluation, and imaging, the causative pathogen often cannot be delineated. Point-of-care-testing systems that provide an opportunity for fast detection of common viruses and some bacteria can therefore influence treatment's options. We aimed to examine whether the Biofire® FilmArray® has an effect on antibiotic treatment, duration of antibiotic therapy, and length of hospital stay within a pediatric cohort. METHODS: We included children who were admitted to inpatient treatment with an acute respiratory tract infection from 02/2017 to 04/2018 using the FA respiratory panel for pathogen detection. The study group data were compared to the retrospective data of children admitted from 02/2016 to 02/2017, using a proprietary multiplex RT-PCR. RESULTS: A total of 322 children of the study group and 464 children of the control group were analyzed for clinical symptoms, laboratory findings, antibiotic treatment, and length of hospital stay. There was no significant reduction (P < .05) of antibiotic treatment and length of hospital stay. CRP, prehospital antibiotic treatment, antibiotic treatment, past medical history, age, and further pathogen detection showed a significant impact on antibiotic therapy, duration of antibiotic treatment, and length of hospital stay. CONCLUSION: The use of the FA did not result in a significant reduction of antibiotic treatment or in length of hospital stay. Other parameters had a more significant impact. Therefore, we suggest that standard operation procedures with therapy guidelines are necessary to provide an effective application of POCT systems.

Detection and clinical characteristics analysis of respiratory viruses in hospitalized children with acute respiratory tract infections by a GeXP-based multiplex-PCR assay.

BACKGROUND: The information regarding viral epidemiology and clinical characteristics in hospitalized children with acute respiratory tract infection (ARTI) in central Fujian is limited. In this study, we aimed at analyzing the viral epidemiology and clinical characteristics of ARTI in hospitalized children admitted to The First Affiliated Hospital of Fujian Medical University. METHODS: Cohort of 386 hospitalized children (31 days to 15 years) diagnosed with ARTI admitted to the Department of Pediatrics from January 1, 2018, to December 31, 2018, was enrolled in this study. Nasopharyngeal swab or sputum samples on the day of hospitalization were tested for 11 viruses via a GeXP-based multiplex-PCR assay. The viral profiles and clinical characteristics were analyzed. RESULTS: The overall positive rate of the samples was 43.26% (167/386). Among the 167 positive samples, 134 (80.24%, 134/167) had a single virus and 33 (19.76%, 33/167) had multiple viruses. There was a significant difference in the frequency of single vs mixed infections among positive samples (80.24% vs 19.76%; χ2  = 122.168, P = .000) as well as among the total examined samples (34.72% vs 8.55%; χ2  = 77.945, P = .000). Human rhinovirus was the most prevalent virus (17.36%, 67/386), followed by influenza A (5.96%, 23/386) and human adenovirus (5.70%, 22/386). There was no significant difference in the etiological distribution of viral pathogens between males and females (χ2  = 0.480, P = .489). Viral infections were more likely to occur in the winter-spring months than in the summer-autumn months (52.51% vs 33.53%, χ2  = 13.830, P = .000). CONCLUSIONS: The GeXP-based multiplex PCR is an accurate and high-throughput assay allows us to quickly detect multiple respiratory viruses simultaneously in pediatric patients. Our study provides information on the viral profiles and clinical characteristics in hospitalized children with ARTI, which would help better effective prevention strategies.

Comparison of four commercial SARS-CoV-2 IgG immuno-assays in RT-PCR negative patients with suspect CT findings.

A subset of patients with Covid-19 presents with negative RT-PCR screening but suspect CT findings. Using four commercially available anti-SARS-CoV-2 IgG immuno-assays, we found this subset constituted 9.2% of all consecutively admitted outpatients with Covid-19 in our hospital. Clinical specificity for Covid-19 of some N protein-based immuno-assays was suboptimal, as positive results were observed in control patients with recent common human coronavirus, influenza B and adenovirus infections.