Functional and genetic predisposition to rhinovirus lower respiratory tract infections in prematurely born infants

Epidemiological characteristics of respiratory viruses in children during the COVID-19 epidemic in Chengdu, China

IMPORTANCE

During the coronavirus disease 2019 epidemic, the Chinese government launched and used a series of nonpharmaceutical interventions (NPIs), including banning social gatherings, wearing face masks, home isolation, and maintaining hand hygiene, to control the disease spread. Whether and how NPIs influence other respiratory viruses in children remain unclear. In this article, we analyzed relative data and found that the number of samples and positive proportion of respiratory viruses decreased significantly compared with that before the epidemic. Clinicians and public health policymakers should pay attention to changes in the epidemic trends and types of respiratory viruses and maintain monitoring of respiratory-related viruses to avoid possible abnormal rebounds and epidemic outbreaks of these viruses.

Early origins of respiratory disease

Chronic respiratory morbidity is unfortunately common in childhood, particularly in those born very prematurely or with congenital anomalies affecting pulmonary development and those with sickle cell disease. Our research group, therefore, has focused on the early origins of chronic respiratory disease. This has included assessing antenatal diagnostic techniques and potentially therapeutic interventions in infants with congenital diaphragmatic hernia. Undertaking physiological studies, we have increased the understanding of the premature baby's response to resuscitation and evaluated interventions in the delivery suite. Mechanical ventilation modes have been optimised and randomised controlled trials (RCTs) with short- and long-term outcomes undertaken. Our studies highlighted respiratory syncytial virus lower respiratory tract infections (LRTIs) and other respiratory viral LRTIs had an adverse impact on respiratory outcomes of prematurely born infants, who we demonstrated have a functional and genetic predisposition to respiratory viral LRTIs. We have described the long-term respiratory outcomes for children with sickle cell disease and importantly identified influencing factors. In conclusion, it is essential to undertake long term follow up of infants at high risk of chronic respiratory morbidity if effective preventative strategies are to be developed.

Predicting the severity of viral bronchiolitis in children

Acute viral bronchiolitis is one of the common causes of hospitalization and mortality, especially among children in the first year of life who have risk factors (prematurity, congenital heart defects, bronchopulmonary dysplasia, immunosuppression). As factors associated with the severe course of bronchiolitis, along with the traditional ones, single nucleotide polymorphisms of the genes of the immune response molecules can be considered.The aim. Based on the analysis of clinical, laboratory and molecular genetic parameters, to identify prognostic criteria for the severe course of acute viral bronchiolitis in children.Materials and methods. The study included 106 children with acute viral bronchiolitis (severe course – 34, mild course – 72), the etiology of which in 67.9 % was respiratory syncytial virus. Forty-seven anamnestic, clinical, traditional laboratory and molecular genetic parameters were assessed as prognostic criteria. Determination of SNP genes of cytokines IL-4 (C-589T), IL-10 (G-1082A), IL-10 (C-592A), IL-10 (C-819T), TNF-α (G-308A), IL-17A (G197A), IL-17F (His161Arg), TLR2-753ArgGln, TLR6-Ser249Pro in venous blood was carried out by the polymerase chain reaction method.Results. An additional criterion for the risk of developing a severe course of bronchiolitis can be the mutant genotype (AA) SNP of the IL-10 gene (C-592A), which was detected exclusively in the group of patients with severe bronchiolitis, increasing the risk of developing a severe disease by 16.11 times (OR = 16.11; 95 % CI: 0.81–121.22, p = 0.02) in conjunction with already established modifying factors: the presence of congenital heart disease, bronchopulmonary dysplasia, prematurity, birth weight < 1500 g. Based on a comprehensive assessment of the established risk factors, a method has been developed that allows calculate the likelihood of developing a severe course of acute viral bronchiolitis. Conclusion. The use of the developed prediction method will not only increase the likelihood of developing severe acute viral bronchiolitis in children, but also determine the priority group among children with predictors of severe viral bronchiolitis for priority immunoprophylaxis against RS-virus infection.

Epidemiology of Respiratory Pathogens in Children with Severe Acute Respiratory Infection and Impact of the Multiplex PCR Film Array Respiratory Panel: A 2-Year Study

Sever acute respiratory infections (SARIs) are a public health issue that are common in children and are associated with an important morbidity and mortality rate worldwide. Although SARI are mainly caused by viruses, they are still a cause of antibiotic overuse. The use of molecular methods especially real-time multiplex PCR allowed to detect a wide range of respiratory viruses and their subtype as well as some atypical bacteria. The aim of this study was to investigate the epidemiology of respiratory pathogens detected in children admitted with SARI and to highlight the role of real-time multiplex PCR in the rapid diagnosis of viral and bacterial SARI. This work is a descriptive observational study from January 2018 to December 2019 including nasopharyngeal secretions collected from 534 children hospitalised in paediatric department. The detection of respiratory viruses and bacteria was performed by the FilmArray® Respiratory Panel. A total of 387 (72.5%) children were tested positive for at least one respiratory pathogen, and 23.3% of them were coinfected with more than one pathogen. Viral aetiology was found in 91.2% (n = 340). The most common viruses detected were HRV (n = 201) and RSV (n = 124), followed by PIV (n = 35) influenza A (n = 29) and human metapneumovirus (n = 27). Bacteria was found in 8.8% (n = 47), and Bordetella pertussis was the most detected. Respiratory syncytial virus and Bordetella pertussis were significantly higher in infants less than 6 months old. The detection of RSV and influenza A presented a pic in winter, and HMPV was statistically significant in spring (p < 0.01). This study described the epidemiology of respiratory pathogens involved in severe respiratory infections in children that were affected by several factors such as season and age group. It also highlighted the importance of multiplex PCR in confirming viral origin, thus avoiding irrational prescription of antibiotics in paediatric settings.

Airway Remodeling Factors During Early-Life Rhinovirus Infection and the Effect of Premature Birth

Background: Early rhinovirus (RV) infection is a strong risk factor for asthma development. Airway remodeling factors play a key role in the progression of the asthmatic condition. We hypothesized that RV infection in young children elicits the secretion of growth factors implicated in airway remodeling and asthma progression. Methods: We examined the nasal airway production of remodeling factors in children ( ≤ 2 years old) hospitalized due to PCR-confirmed RV infection. Airway remodeling proteins included: MMP-1, MMP-2, MMP-7, MMP-9, MMP-10, TIMP-1, TIMP-2, EGF, Angiopoietin-2, G-CSF, BMP-9, Endoglin, Endothelin-1, Leptin, FGF-1, Follistatin, HGF, HB-EGF, PLGF, VEGF-A, VEGF-C, VEGF-D, FGF-2, TGF-β1, TGF-β2, TGF-β3, PDGF AA, PDGF BB, SPARC, Periostin, OPN, and TGF-α. Results: A total of 43 young children comprising RV cases (n = 26) and uninfected controls (n = 17) were included. Early RV infection was linked to (1) enhanced production of several remodeling factors (e.g., HGF, TGFα), (2) lower MMP-9/TIMP-2 and MMP-2/TIMP-2 ratios, and (3) increased MMP-10/TIMP-1 ratios. We also found that relative to term infants, severely premature children had reduced MMP-9/TIMP-2 ratios at baseline. Conclusion: RV infection in young children elicits the airway secretion of growth factors implicated in angiogenesis, fibrosis, and extracellular matrix deposition. Our results highlight the potential of investigating virus-induced airway remodeling growth factors during early infancy to monitor and potentially prevent chronic progression of respiratory disorders in all ages.

Participant retention in follow-up studies of prematurely born children

Background

Follow-up studies of infants born prematurely are essential to understand the long-term consequences of preterm birth and the efficacy of interventions delivered in the neonatal period. Retention of participants for follow-up studies, however, is challenging, with attrition rates of up to 70%. Our aim was to examine retention rates in two follow-up studies of prematurely born children and identify participant or study characteristics that were associated with higher attrition, and to discuss retention strategies with regard to the literature.

Methods

Data from children recruited at birth to one of two studies of prematurely born infants were assessed. The two studies were the United Kingdom Oscillation Study (UKOS, a randomised study comparing two modes of neonatal ventilation in infants born less than 29 weeks of gestational age (GA)), and an observational study examining the impact of viral lower respiratory tract infections in infancy in those born less than 36 weeks of GA (virus study). The UKOS participants, but not those in the virus study, had regularly been contacted throughout the follow-up period. UKOS subjects were followed up at 11 to 14 years of age and subjects in the virus study at 5–7 years of age. At follow up in both studies, pulmonary function and respiratory morbidity were assessed. Retention rates to follow-up in the two studies and baseline characteristics of those who were and were not retained were assessed.

Results

Retention was significantly higher in UKOS than the virus study (61% versus 35%, p < 0.0001). Subjects lost to UKOS follow up had greater deprivation scores (p < 0.001), a greater likelihood of intrauterine tobacco exposure (p = 0.001) and were more likely to be of non-white ethnicity (p < 0.001). In the virus study, those lost to follow-up had higher birth weights (p = 0.036) and were less likely to be oxygen dependent at hospital discharge (p = 0.003) or be part of a multiple birth (p = 0.048).

Conclusions

Higher retention was demonstrated when there was regular contact in the follow-up period. Both social factors and initial illness severity affected the retention into follow-up studies of prematurely born infants, though these factors were not consistent across the two studies.

Paediatric Virology and respiratory syncytial virus: An interview with Honorary Senior Lecturer in Paediatric Infectious Diseases Dr Simon B. Drysdale (St. George's, University of London, UK)

Dr Simon B. Drysdale, Consultant and Honorary Senior Lecturer in Paediatric Infectious Diseases at St. George's University Hospitals NHS Foundation Trust and St. George's, University of London, is one of the most talented early career academic specialists in Paediatric Infectious Diseases in the United Kingdom. His main research interest is respiratory syncytial virus (RSV); he is particularly interested in understanding the host susceptibility to RSV, the management of RSV infection and associated health economics and the development of treatments and immunisations/vaccines, which are currently lacking. According to Dr Drysdale, RSV is a significant cause of morbidity and mortality among young infants and older adults, particularly those with co-morbidities. While there is ample RSV epidemiological and healthcare cost data available for young infants and children, more data is required for older children and adults. There are currently several antiviral medications for the treatment of RSV infection in development; however, none have yet progressed beyond Phase 2 clinical trials. Multiple types of novel therapeutic molecules have been developed, including fusion and non-fusion inhibitors and polymerase inhibitors aimed at various RSV targets, such as the F protein and RNA polymerase. In recent years, great strides have been made with regards to an RSV vaccine or monoclonal antibody, with >40 candidates currently in development. A maternal RSV vaccine, which just completed a Phase 3 trial, was shown to have 44% efficacy against hospitalization for RSV lower respiratory tract infection in infants. A new long-acting monoclonal antibody against RSV infection, having shown excellent promise in a Phase 2 trial in infants, is about to be investigated in a Phase 3 clinical trial commencing shortly.

Vitamin D status and vitamin D receptor gene polymorphism in Saudi children with acute lower respiratory tract infection

There is a significant association exists between vitamin D deficiencies, low respiratory tract infections, and certain types of VDR gene polymorphism. Various studies are being conducted to prove any such link between the different clinical conditions due to disturbed vitamin D regulation and VDR gene polymorphisms. The present study analyzed the presence of vitamin D receptor (VDR) gene polymorphisms (ApaI and TaqI) in Saudi pediatric patient suffering from acute lower respiratory tract infection (ALRTI) cases. Fifty children (50) with ALRTI admitted at King Saud University Medical City, Riyadh/Saudi Arabia were included in addition to seventy-three (73) apparently healthy children who were considered as the control group. Genomic DNA from whole blood was extracted and subjected to polymerase chain reaction (PCR) targeting TaqI and ApaI VDR polymorphisms. RFLP-PCR genotyping was performed to determine the allelic frequency within the VDR gene. In the whole sample, the allelic frequency of ApaI polymorphism in the VDR gene was 58.5%, 17.9%, and 23.6% for AA, Aa, and aa respectively (p = 0.11), while it was 48%, 19%, and 33% for TT, Tt, and tt respectively (p = 0.33) with regards to the frequency of TaqI polymorphism in the VDR gene. VDR ApaI Aa and aa genotypes and VDR TaqI Tt and tt genotypes were not associated with increased risk of ALRTI in children (OR 0.87, 95% CI 0.33-2.28, p = 0.77; OR 0.56, 95% CI 0.23-1.4, p = 0.21; OR 1.15, 95% CI 0.44-2.99, p = 0.77; OR 0.73, 95% CI 0.32-1.68, p = 0.46 respectively). To conclude, neither vitamin D status nor VDR gene polymorphisms such as ApaI and TaqI is associated with increased susceptibility to ALRTI. Linkage disequilibrium was not detected between ApaI and TaqI VDR gene polymorphisms as in the case of serum vitamin D status in ALRTI patients versus apparent healthy children.

Rhinovirus - From bench to bedside

Rhinovirus has been neglected in the past because it was generally perceived as a respiratory virus only capable of causing mild common cold. Contemporary epidemiological studies using molecular assays have shown that rhinovirus is frequently detected in adult and pediatric patients with upper or lower respiratory tract infections. Severe pulmonary and extrapulmonary complications are increasingly recognized. Contrary to popular belief, some rhinoviruses can actually replicate well at 37 °C and infect the lower airway in humans. The increasing availability of multiplex PCR panels allows rapid detection of rhinovirus and provides the opportunity for timely treatment and early recognition of outbreaks. Recent advances in the understanding of host factors for viral attachment and replication, and the host immunological response in both asthmatic and non-asthmatic individuals, have provided important insights into rhinovirus infection which are crucial in the development of antiviral treatment. The identification of novel drugs has been accelerated by repurposing clinically-approved drugs. As humoral antibodies induced by past exposure and vaccine antigen of a particular serotype cannot provide full coverage for all rhinovirus serotypes, novel vaccination strategies are required for inducing protective response against all rhinoviruses.

Nutritional modulation of age-related changes in the immune system and risk of infection

The immune system undergoes some adverse alterations during aging, many of which have been implicated in the increased morbidity and mortality associated with infection in the elderly. In addition to intrinsic changes to the immune system with aging, the elderly are more likely to have poor nutritional status, which further impacts the already impaired immune function. Although the elderly often have low zinc serum levels, several manifestations commonly observed during zinc deficiency are similar to the changes in immune function with aging. In the case of vitamin E, although its deficiency is rare, the intake above recommended levels is shown to enhance immune functions in the elderly and to reduce the risk of acquiring upper respiratory infections in nursing home residents. Vitamin D is a critical vitamin in bone metabolism, and its deficiency is far more common, which has been linked to increased risk of infection as demonstrated in a number of observational studies including those in the elderly. In this review, we focus on zinc, vitamin E, and vitamin D, the 3 nutrients which are relatively well documented for their roles in impacting immune function and infection in the elderly, to discuss the findings in this context reported in both the observational studies and interventional clinical trials. A perspective will be provided based on the analysis of information under review.