Respiratory Syncytial Virus and Metapneumovirus Infection Have Different Clinical Presentation in Children

Respiratory syncytial virus (RSV) and Human metapneumovirus (hMPV), members of Pneumoviridae family are common causes of acute respiratory tract infections (ARTI) among children. Study material includes routine nasopharyngeal samples obtained during 8-year period for hMPV and one single season for RSV in children aged 0 to 15 years at the Centre Hospitalier Universitaire (CHU) Saint Pierre in Brussels. Positive samples for RSV or hMPV identified by viral culture, lateral flow chromatography test for RSV or direct fluorescent assay for hMPV were selected retrospectively. The medical charts of these patients were reviewed. Hospitalization rate was 37% (219/591) and 39% (187/476) for hMPV and RSV respectively. Children hospitalized for RSV infection were significantly younger and more dyspneic, requiring more respiratory support, longer hospital stay and transfers in Pediatric intensive Care Units (PICU) than those hospitalized for hMPV infection. Pneumonia diagnostic and antibiotics therapies were more significantly associated with hMPV infections.In conclusion, despite their genetic similarities, RSV and hMPV present epidemiological and clinical differences in pediatric infections.

Molecular typing and epidemiologic profiles of human metapneumovirus infection among children with severe acute respiratory infection in Huzhou, China

Background Human metapneumovirus (hMPV) is one of the important pathogens in infant respiratory tract infection. However, the molecular epidemiology of hMPV among children < 14 years of age hospitalized with severe acute respiratory infection (SARI) is unclear. We investigated the hMPV infection status and genotypes of children hospitalized with SARI from January 2016 to December 2020 in Huzhou, China. Methods A nasopharyngeal flocked swab, nasal wash, or nasopharyngeal swab/or opharyngeal swab combination sample was collected from children with SARI in Huzhou from January 2016 to December 2020. Quantitative reverse transcription-polymerase chain reaction was performed to detect hMPV RNA. The hMPV F gene was amplified and sequenced, followed by analysis using MEGA software (ver. 7.0). Epidemiological data were analyzed using Microsoft Excel 2010 and SPSS (ver. 22.0) software. Results A total of 1133 children with SARI were recruited from 2016 to 2020. Among them, 56 (4.94%) were positive for hMPV-RNA. Children < 5 years of age accounted for 85.71% of the positive cases. The hMPV incidence was high in spring and winter, especially in December and January to March. Phylogenetic analysis of the F-gene sequences of 28 hMPV strains showed that the A1, B1, and B2 genotypes were prevalent in Huzhou, and the dominant hMPV genotype varied according to surveillance year. Conclusions HMPV is an important respiratory pathogen in children in Huzhou, with a high incidence in winter and spring in children < 5 years of age. In this study, genotypes A1, B1, and B2 were the most prevalent.

Avian Cell Line DuckCelt®-T17 Is an Efficient Production System for Live-Attenuated Human Metapneumovirus Vaccine Candidate Metavac®

The development of a live-attenuated vaccine (LAV) for the prevention of human metapneumovirus (HMPV) infection is often hampered by the lack of highly efficient and scalable cell-based production systems that support eventual global vaccine production. Avian cell lines cultivated in suspension compete with traditional cell platforms used for viral vaccine manufacture. We investigated whether the DuckCelt®-T17 avian cell line (Vaxxel), previously described as an efficient production system for several influenza strains, could also be used to produce a new HMPV LAV candidate (Metavac®, SH gene-deleted A1/C-85473 HMPV). To that end, we characterized the operational parameters of MOI, cell density, and trypsin addition to achieve the optimal production of Metavac®, and demonstrated that the DuckCelt®-T17 cell line is permissive and well-adapted to the production of the wild-type A1/C-85473 HMPV and the Metavac® vaccine candidate. Moreover, our results confirmed that the LAV candidate produced in DuckCelt®-T17 cells conserves its advantageous replication properties in LLC-MK2 and 3D-reconstituted human airway epithelium models, and its capacity to induce efficient neutralizing antibodies in a BALB/c mouse model. Our results suggest that the DuckCelt®-T17 avian cell line is a very promising platform for the scalable in-suspension serum-free production of the HMPV-based LAV candidate Metavac®.

The Prevalence and Genetic Characterization of Human Metapneumovirus in Bulgaria, 2016–2019

<b><i>Introduction:</i></b> We investigated the prevalence of human metapneumovirus (hMPV) among patients with acute respiratory infections in Bulgaria, and performed genetic characterization of the F gene of these strains. <b><i>Methods:</i></b> Nasopharyngeal swabs collected from patients of a range of ages were tested by using real-time PCR for 12 respiratory viruses. The F gene was sequenced, and phylogenetic and amino acid analyses of the F gene/protein were performed. <b><i>Results:</i></b> A total of 1,842 patients were examined during a 3-year period; 1,229 patients (66.7%) were positive for at least one respiratory virus. hMPV was identified in 83 (4.5%) patient samples. Eleven (13%) of hMPV-positive patients were coinfected with another respiratory virus. The hMPV incidence rate in the 2016/2017, 2017/2018, and 2018/2019 winter seasons was 5.4, 5.4, and 3.1%, respectively. hMPV was mainly detected in specimens collected between January and May (89.2% of cases). The incidence of hMPV infection was highest (5.1%) among the youngest age-group (0–4 years), where hMPV was a causative agent in 8.1 and 4.8% of bronchiolitis and pneumonia cases, respectively. Among the patients aged ≥5 years, hMPV was detected in 2.2 and 3.2% of cases of pneumonia and central nervous system infections, respectively. Phylogenetic analysis of the F gene showed that the sequenced hMPV strains belonged to the A2b, B1, and B2 genotypes. Numerous amino acid substitutions were identified compared with the NL00/1 prototype strain. <b><i>Conclusion:</i></b> This study revealed the significant role of hMPV as a causative agent of serious respiratory illnesses in early childhood, and also demonstrated year-to-year changes in hMPV prevalence and genetic diversity in circulating strains.

Molecular Typing and Epidemiology Profiles of Human Metapneumovirus Infection Among Children With Severe Acute Respiratory Infection in Huzhou, China

Background: Human metapneumovirus (hMPV) is one of the important pathogens of infant respiratory tract infection. However, the molecular epidemiological information relating to hMPV among children hospitalized patients with severe acute respiratory infection (SARI) have not been thoroughly studied as yet. To investigate the infection status and genotypes of hMPV among children hospitalized patients with SARI from January 2016 to December 2020 in Huzhou, China. Methods: A nasopharyngeal flocked swab, nasal wash or combination of nasopharyngeal swab and oropharyngeal swab samples were collected from children with SARI in Huzhou from January 2016 to December 2020. RT-PCR was used to detect the nucleic acid of hMPV. F gene was amplified and sequenced for the positive nucleic acid samples of hMPV. The obtained gene sequences were analyzed by MEGA software (version 7.0). Epidemiological data were analyzed using Microsoft Excel 2010 and service solutions (SPSS) 21.0 software.Results: A total of 1133 children with SARI were collected from 2016 to 2020. Among them, 56 cases were positive for hMPV nucleic acid, with a positive rate of 4.94%. Children under 5 years old accounted for 85.71% of the total positive cases. Higher activity of hMPV infection could be seen in the period in Spring and Winter. and the main epidemic months were December and January-March. The F gene sequences of 28 strains of hMPV were obtained by co-sequencing. Phylogenetic analysis showed that there were A1, B1 and B2 genotypes of hMPV prevalent in Huzhou, and the dominant genotype of hMPV during our study period varied according to surveillance year.Conclusions: HMPV is one of the important pathogens causing acute respiratory virus infection in children in Huzhou, with high incidence in winter and spring seasons and children under the age of 5，A1, B1 and B2 are three prevalent genotypes.

Induction of Protective Immunity by a Single Low Dose of a Master Cell Bank cGMP-rBCG-P Vaccine Against the Human Metapneumovirus in Mice

Human metapneumovirus (hMPV) is an emergent virus, which mainly infects the upper and lower respiratory tract epithelium. This pathogen is responsible for a significant portion of hospitalizations due to bronchitis and pneumonia in infants and the elderly worldwide. hMPV infection induces a pro-inflammatory immune response upon infection of the host, which is not adequate for the clearance of this pathogen. The lack of knowledge regarding the different molecular mechanisms of infection of this virus has delayed the licensing of effective treatments or vaccines. As part of this work, we evaluated whether a single and low dose of a recombinant Mycobacterium bovis Bacillus Calmette-Guérin (BCG) expressing the phosphoprotein of hMPV (rBCG-P) can induce a protective immune response in mice. Immunization with the rBCG-P significantly decreased neutrophil counts and viral loads in the lungs of infected mice at different time points. This immune response was also associated with a modulated infiltration of innate cells into the lungs, such as interstitial macrophages (IM) and alveolar macrophages (AM), activated CD4+ and CD8+ T cells, and changes in the population of differentiated subsets of B cells, such as marginal zone B cells and plasma cells. The humoral immune response induced by the rBCG-P led to an early and robust IgA response and a late and constant IgG response. Finally, we determined that the transfer of cells or sera from immunized and infected mice to naïve mice promoted an efficient viral clearance. Therefore, a single and low dose of rBCG-P can protect mice from the disease caused by hMPV, and this vaccine could be a promising candidate for future clinical trials.

Molecular Epidemiology of Human Metapneumovirus Infection among Children with Severe Acute Respiratory Infection in Huzhou from 2016 to 2020

Background: Human metapneumovirus (hMPV) is one of the important pathogens of infant respiratory tract infection. However, the molecular epidemiological information relating to hMPV among children hospitalized patients with severe acute respiratory infection (SARI) have not been thoroughly studied as yet. To investigate the infection status and genotypes of hMPV among children hospitalized patients with SARI from January 2016 to December 2020 in Huzhou, China. Methods: A nasopharyngeal flocked swab, nasal wash or combination of nasopharyngeal swab and oropharyngeal swab samples were collected from children with SARI in Huzhou from January 2016 to December 2020. RT-PCR was used to detect the nucleic acid of hMPV. F gene was amplified and sequenced for the positive nucleic acid samples of hMPV. The obtained gene sequences were analyzed by MEGA software (version 7.0). Epidemiological data were analyzed using Microsoft Excel 2010 and service solutions (SPSS) 21.0 software.Results: A total of 1133 children with SARI were collected from 2016 to 2020. Among them, 56 cases were positive for hMPV nucleic acid, with a positive rate of 4.94%. Children under 5 years old accounted for 85.71% of the total positive cases. Higher activity of hMPV infection could be seen in the period in Spring and Winter. and the main epidemic months were December and January-March. The F gene sequences of 28 strains of hMPV were obtained by co-sequencing. Phylogenetic analysis showed that there were A1, B1 and B2 genotypes of hMPV prevalent in Huzhou, and the dominant genotype of hMPV during our study period varied according to surveillance year.Conclusions: HMPV is one of the important pathogens causing acute respiratory virus infection in children in Huzhou, with high incidence in winter and spring seasons and children under the age of 5，A1, B1 and B2 are three prevalent genotypes.

Molecular Typing and Epidemiology Profiles of Human Metapneumovirus Infection Among Children With Severe Acute Respiratory Infection in Huzhou, China

Background: Severe acute respiratory infections (SARI) threaten human health and cause a large number of hospitalized patients every year. However, as one of the most common pathogen that cause acute respiratory tract infection, the molecular epidemiological information relating to hMPV among patients with SARI is limited. Here, we evaluate the epidemiological and molecular characteristics of hMPV infections among children hospitalized patients with SARI from January 2016 to December 2020 in Huzhou, China.Methods: From January 2016 to December 2020, a total of 1133 nasopharyngeal swabs collected from children inpatients with SARI were screened for hMPV by real-time PCR. All samples that tested positive for hMPV were further typed by sequencing partial sequences of hexon gene. Genotypes of hMPV were confirmed by phylogenetic analysis. Epidemiological data were analyzed using Microsoft Excel 2010 and service solutions (SPSS) 21.0 software.Results: 56 (4.94%) samples were positive for hMPV, children under 5 years old accounted for 85.71% (48/56) of the infections. Higher activity of hMPV infection could be seen in the period in Spring and Winter. 3 different types of hMPV were identified in hospitalized SARI cases, with hMPV-B1 (42.86 %) was the most prevalent types, followed by HAdV-B2 (35.71 %) and hMPV-A1(21.42 %). The predominant genotypes of hMPV during our study period varied according to surveillance year. Overall, 1 type (hMPV-B1) were detected in 2016, 2 different types(hMPV-B1 and HAdV-A1) were detected in 2017, 3 different types(hMPV-B1, hMPV-B2 and hMPV-A1) were detected in 2018, 2 different types(hMPV-B1 and hMPV-B2) were detected in 2019, 1 type (hMPV-B2) were detected in 2020.Conclusions: This study revealed the prevalence and the molecular epidemiological characteristics of hMPV infections among children hospitalized patients with SARI in Huzhou from January 2016 to December 2020. The hMPV prevalence is related to age and season. As the most prevalent hMPV types, hMPV-B1 was co-circulating with other types and presented an alternate prevalence pattern.

Epidemiology and genotypic diversity of human metapneumovirus in paediatric patients with acute respiratory infection in Beijing, China

Background Acute respiratory tract infections (ARTIs) causes high amounts of morbidity and mortality worldwide every year. Human metapneumovirus (HMPV) is a major pathogen of ARTIs in children. In this study, we aimed to investigate the epidemiology and genotypic diversity of HMPV in children hospitalized with ARTIs in Beijing, China. Methods Hospitalized children aged < 14 years with ARTIs were enrolled from April 2017 to March 2018; nasopharyngeal aspirates were collected and subjected to real-time polymerase chain reaction tests for HMPV. HMPV-positive samples were genotyped based on a partial N gene. Whole genome sequences were determined for samples with high viral loads. Results 4.08% (52/1276) enrolled paediatric patients were identified as having HMPV infection. The epidemic season is winter and early spring, children aged ≤ 4 years were more susceptible to HMPV infection (47/52, 90.38%). The co-infection rate were 36.54% (19/52), the most common co-infected virus were influenza and respiratory syncytial virus. The main diagnoses of HMPV infection were pneumonia (29/52, 55.77%) and bronchitis (23/52, 44.23%), while the main clinical manifestations were cough, fever, rhinorrhoea, and sneeze. Among 48 HMPV-positive specimens, A2b (19/48, 39.58%) and B1 (26/48, 54.17%) were the main epidemic subtypes. Patients with HMPV genotype A infection had a higher viral load compared to genotype B patients (6.07 vs. 5.37 log10 RNA copies/ml). Five complete sequences of HMPV were obtained. This is the first report of a whole genome sequence of HMPV-B1 isolated in China. Conclusions HMPV is an important respiratory pathogen in paediatric patients. Cases of HMPV infection could burden hospitals in the epidemic season. HMPV viral loads and genotypes have no correlation with co-infection or clinical characteristics.

The Pivotal Role of Viruses in the Pathogeny of Chronic Lymphocytic Leukemia: Monoclonal (Type 1) IgG K Cryoglobulinemia and Chronic Lymphocytic Leukemia Diagnosis in the Course of a Human Metapneumovirus Infection

Background: Type-1 cryoglobulinemia (CG) is a rare disease associated with B-cell lymphoproliferative disorder. Some viral infections, such as Epstein–Barr Virus infections, are known to cause malignant lymphoproliferation, like certain B-cell lymphomas. However, their role in the pathogenesis of chronic lymphocytic leukemia (CLL) is still debatable. Here, we report a unique case of Type-1 CG associated to a CLL transformation diagnosed in the course of a human metapneumovirus (hMPV) infection. Case presentation: A 91-year-old man was initially hospitalized for delirium. In a context of febrile rhinorrhea, the diagnosis of hMPV infection was made by molecular assay (RT-PCR) on nasopharyngeal swab. Owing to hyperlymphocytosis that developed during the course of the infection and unexplained peripheral neuropathy, a type-1 IgG Kappa CG secondary to a CLL was diagnosed. The patient was not treated for the CLL because of Binet A stage classification and his poor physical condition. Conclusions: We report the unique observation in the literature of CLL transformation and hMPV infection. We provide a mini review on the pivotal role of viruses in CLL pathophysiology.