Human Rhinovirus Infection in Children with Cystic Fibrosis

Impact of viral respiratory infections on pulmonary exacerbations in children with cystic fibrosis

BACKGROUND

Viral respiratory infections trigger pulmonary exacerbations (PEs) in children with cystic fibrosis (CF), but their clinical impact is not well understood.

METHODS

A retrospective review of pediatric patients with CF who underwent nasopharyngeal respiratory viral panel testing during hospitalization for a PE between 2011 and 2018 was conducted. Patients were dichotomized into viral-positive and viral-negative groups. The results of spirometry, respiratory cultures, duration of hospitalization, and risk for subsequent PEs were analyzed.

RESULTS

Ninety-five patients had 210 hospitalizations for PE (viral-positive = 71/210, 34%) during the study period. Rhinovirus/enterovirus was the most common virus (52/71, 73%) identified. Viral-positive patients were younger (p < 0.001), had higher baseline forced expiratory volume in 1 s (FEV1) (p = 0.037), continued to maintain higher FEV1 at 3 and 6 months following PE (p = 0.003 and 0.002, respectively), and had a shorter duration of hospitalization (p = 0.006) compared to the viral-negative group. There was no difference between the two groups in the rate of recovery of FEV1 at 3 and 6 months following PE (p = 0.71 and 0.405, respectively), time to the next PE (hazard ratio = 1.34, p = 0.157), number of subsequent PEs in 6 months (p = 0.99), or Pseudomonas aeruginosa (PA) acquisition (p = 0.707).

CONCLUSIONS

In this single pediatric CF center cohort, one-third of PEs requiring hospitalization were associated with a viral infection, with rhinovirus/enterovirus being the most common. Viral-positive PEs were not associated with a greater decline or delayed recovery of lung function, increased risk for PA acquisition, shortened duration to next PE, longer hospital stay, or an increase in the frequency of subsequent PEs in 6 months compared to viral-negative PEs.

Divergent dynamics of inflammatory mediators and multiplex PCRs during airway infection in cystic fibrosis patients and healthy controls: Serial upper airway sampling by nasal lavage

BACKGROUND

In cystic fibrosis (CF), acute respiratory exacerbations critically enhance pulmonary destruction. Since these mainly occur outside regular appointments, they remain unexplored. We previously elaborated a protocol for home-based upper airway (UAW) sampling obtaining nasal-lavage fluid (NLF), which, in contrast to sputum, does not require immediate processing. The aim of this study was to compare UAW inflammation and pathogen colonization during stable phases and exacerbations in CF patients and healthy controls.

METHODS

Initially, we obtained NLF by rinsing 10 ml of isotonic saline/nostril during stable phases. During exacerbations, subjects regularly collected NLF at home. CF patients directly submitted one aliquot for microbiological cultures. The remaining samples were immediately frozen until transfer on ice to our clinic, where PCR analyses were performed and interleukin (IL)-1β/IL-6/IL-8, neutrophil elastase (NE), matrix metalloproteinase (MMP)-9, and tissue inhibitor of metalloproteinase (TIMP)-1 were assessed.

RESULTS

Altogether, 49 CF patients and 38 healthy controls (HCs) completed the study, and 214 NLF samples were analyzed. Of the 49 CF patients, 20 were at least intermittently colonized with P. aeruginosa and received azithromycin and/or inhaled antibiotics as standard therapy. At baseline, IL-6 and IL-8 tended to be elevated in CF compared to controls. During infection, inflammatory mediators increased in both cohorts, reaching significance only for IL-6 in controls (p=0.047). Inflammatory responses tended to be higher in controls [1.6-fold (NE) to 4.4-fold (MMP-9)], while in CF, mediators increased only moderately [1.2-1.5-fold (IL-6/IL-8/NE/TIMP-1/MMP-9)]. Patients receiving inhalative antibiotics or azithromycin (n=20 and n=15, respectively) revealed lower levels of IL-1β/IL-6/IL-8 and NE during exacerbation compared to CF patients not receiving those antibiotics. In addition, CF patients receiving azithromycin showed MMP-9 levels significantly lower than CF patients not receiving azithromycin at stable phase and exacerbation. Altogether, rhinoviruses were the most frequently detected virus, detected at least once in n=24 (49.0%) of the 49 included pwCF and in n=26 (68.4%) of the 38 healthy controls over the 13-month duration of the study. Remarkably, during exacerbation, rhinovirus detection rates were significantly higher in the HC group compared to those in CF patients (65.8% vs. 22.4%; p<0.0001).

CONCLUSION

Non-invasive and partially home-based UAW sampling opens new windows for the assessment of inflammation and pathogen colonization in the unified airway system.

TLR2-mediated innate immune priming boosts lung anti-viral immunity

BACKGROUND

We assessed whether Toll-like receptor (TLR)2 activation boosts the innate immune response to rhinovirus infection, as a treatment strategy for virus-induced respiratory diseases.

METHODS

We employed treatment with a novel TLR2 agonist (INNA-X) prior to rhinovirus infection in mice, and INNA-X treatment in differentiated human bronchial epithelial cells derived from asthmatic-donors. We assessed viral load, immune cell recruitment, cytokines, type I and III interferon (IFN) production, as well as the lung tissue and epithelial cell immune transcriptome.

RESULTS

We show, in vivo, that a single INNA-X treatment induced innate immune priming characterised by low-level IFN-λ, Fas ligand, chemokine expression and airway lymphocyte recruitment. Treatment 7 days before infection significantly reduced lung viral load, increased IFN-β/λ expression and inhibited neutrophilic inflammation. Corticosteroid treatment enhanced the anti-inflammatory effects of INNA-X. Treatment 1 day before infection increased expression of 190 lung tissue immune genes. This tissue gene expression signature was absent with INNA-X treatment 7 days before infection, suggesting an alternate mechanism, potentially via establishment of immune cell-mediated mucosal innate immunity. In vitro, INNA-X treatment induced a priming response defined by upregulated IFN-λ, chemokine and anti-microbial gene expression that preceded an accelerated response to infection enriched for nuclear factor (NF)-κB-regulated genes and reduced viral loads, even in epithelial cells derived from asthmatic donors with intrinsic delayed anti-viral immune response.

CONCLUSION

Airway epithelial cell TLR2 activation induces prolonged innate immune priming, defined by early NF-κB activation, IFN-λ expression and lymphocyte recruitment. This response enhanced anti-viral innate immunity and reduced virus-induced airway inflammation.

A bird eye view on cystic fibrosis: An underestimated multifaceted chronic disorder

Cystic fibrosis (CF) is an autosomal recessive disease which involves the mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF involves in the inflammatory processes and is considered as a multisystem disorder that is not confined to lungs, but it also affects other vital organs that leads to numerous co-morbidities. The respiratory disorder in the CF results in mortality and morbidity which is characterized by series of serious events involving mucus hypersecretion, microbial infections, airways obstruction, inflammation, destruction of epithelium, tissue remodeling and terminal lung diseases. Mucins are the high molecular weight glycoproteins important for the viscoelastic properties of the mucus, play a significant role in the disease mechanisms. Determining the functional association between the CFTR and mucins might help to identify the putative target for specific therapeutic approach. In fact, furin enzyme which helps in the entry of novel COVID-19 virus into the cell, is upregulated in CF and this can also serve as a potential target for CF treatment. Moreover, the use of nano-formulations for CF treatment is an area of research being widely studied as they have also demonstrated promising outcomes. The in-depth knowledge of non-coding RNAs like miRNAs and lncRNAs and their functional association with CFTR gene expression and mutation can provide a different range of opportunity to identify the promising therapeutic approaches for CF.

The role of rhinovirus infections in young children with cystic fibrosis

Rhinovirus (RV) is an important virus in children with chronic respiratory conditions such as asthma; however, little is known about its role in CF. Our aim was to examine the prevalence and clinical impact of different RV species in young children with CF. We collected clinical data and nasal swabs on patients at home and in the hospital setting. Parents filled out symptom diaries and collected nasal swabs when their children were symptomatic and asymptomatic. A novel RV typing PCR assay was used to determine the RV species present. We collected 55 nasal swab samples from ten preschool CF patients over a six month period. The quality of parent collected samples at home was sufficient for PCR analysis. RV was the most common virus detected in young children with CF. There was no difference in the frequency of RV species between symptomatic and asymptomatic subjects. However, parental home-sampling is an acceptable and feasible approach to monitoring young children with CF.

The prevalence of viral infections in children with cystic fibrosis in a tertiary care center in Saudi Arabia

Introduction

Studies have shown that pulmonary exacerbations in cystic fibrosis (CF) patients are associated with respiratory viruses. The most common agent causing viral infections in patients with CF before the age of 3 years is respiratory syncytial virus.

Objectives

To obtain the prevalence of the different types of viral infection in CF patients and to identify its relation with the type of bacterial infection, (CFTR) mutations and pulmonary function test (PFT).

Methodology

A retrospective charts review of 387 patients with CF of all age groups who were screened for the detection of viruses during respiratory exacerbation from the period of January 1, 1984 to June 1, 2016.

Results

A total of 159 CF patients had pulmonary exacerbation and had viral PCR obtained. Fifty-eight patients (36%) had positive viral PCR. Males were more commonly infected in 30/58 patients (52%) compared to females in 28 patients (48%). Forty-five of 58 patients (78%) were alive and 13 patients (22%) died. Rhinovirus was the most frequently reported viral PCR in 33/74 sample (45%). Out of 74 viral PCR, 41 (55.4%) were during the colder seasons (October–February) and 33 (44.5%) during the warmer seasons (March–September). During viral infection and viral recurrence, there was an increase in bacterial colonization specifically of H. influenza and staphylococcus aureus. The most common CFTR mutation for the CF viral infection is: 3120+1G>A in Intron 16 in 11/57 patients (19%). The Eastern Province had the highest viral infection of 24 out of 57 patients (42%). Follow-up PFT post viral infection showed no significant difference in the type and the severity of PFT compared to the initial PFT during the viral illness.

Conclusion

Viral infections contributed to the increase in morbidity and mortality of CF patients in our population, and rhinovirus was the most common causative agent. Viral infections and viral recurrence increased the prevalence of bacterial infection of specific pathogens such as H. influenza and S. aureus. Physicians should be aware to prevent progressive lung damage in CF patients by treating the concomitant viral and bacterial infections. Viral infection may be associated with some common CFTR mutations.

Viruses in cystic fibrosis patients' airways

Although bacteria have historically been considered to play a major role in cystic fibrosis (CF) airway damage, a strong impact of respiratory viral infections (RVI) is also now recognized. Emerging evidence confirms that respiratory viruses are associated with deterioration of pulmonary function and exacerbation and facilitation of bacterial colonization in CF patients. The aim of this review is to provide an overview of the current knowledge on respiratory viruses in CF airways, to discuss the resulting inflammation and RVI response, to determine how to detect the viruses, and to assess their clinical consequences, prevalence, and interactions with bacteria. The most predominant are Rhinoviruses (RVs), significantly associated with CF exacerbation. Molecular techniques, and especially multiplex PCR, help to diagnose viral infections, and the coming rise of metagenomics will extend knowledge of viral populations in the complex ecosystem of CF airways. Prophylaxis and vaccination are currently available only for Respiratory syncytial and Influenza virus (IV), but antiviral molecules are being tested to improve CF patients' care. All the points raised in this review highlight the importance of taking account of RVIs and their potential impact on the CF airway ecosystem.

Association of rhinovirus with exacerbations in young children affected by cystic fibrosis: Preliminary data

Rhinovirus (RV) is a common respiratory viral infection linked to worsening of chronic respiratory diseases including cystic fibrosis (CF) and asthma. RV was tested by RT-PCR in samples (n = 465) collected from the upper (nasal swab, oropharyngeal suction, and sputum) and lower (bronchoalveolar washings) respiratory tract of 110 children with CF. Air samples (n = 52) collected from the operating theatres and outpatient clinics were tested for RV. RV was found in 43% of children <5 years suffering an exacerbation, and 12% of older children (5-17 years). RV particles were detected in the air of clinic rooms. Detection of RV is important in better understanding viral infections in patients with CF.

Frequency and Duration of Rhinovirus Infections in Children With Cystic Fibrosis and Healthy Controls: A Longitudinal Cohort Study

BACKGROUND

Respiratory viral infections are an important cause of morbidity in patients with chronic respiratory diseases, such as cystic fibrosis (CF). We hypothesized that patients with CF are more susceptible to human rhinovirus (HRV) infections than healthy controls.

METHODS

In a 6-month winter period, 20 young children with CF (0-7 years) and 18 age-matched healthy controls were sampled biweekly for HRV-polymerase chain reaction using nasopharyngeal swabs, irrespective of respiratory symptoms. Respiratory symptoms were scored twice a week. If any symptom was present, an additional sample was obtained. All HRV-positive samples were genotyped to distinguish HRV subtypes.

RESULTS

We analyzed 645 samples, with comparable total numbers of samples in both groups. HRV was detected in 40.8% of all analyzed samples. Children with CF had significantly more HRV-positive samples compared with healthy controls, with a mean number (± standard deviation) of 8.1 ± 2.3 versus 5.7 ± 2.9 positive samples per individual (P < 0.01). Prolonged detection (>2 weeks) with the same HRV subtype occurred more frequently in the CF patients (P < 0.01). The genetic distribution and pattern of phylogenetic diversity of the different HRV subtypes were similar in both groups.

CONCLUSIONS

This is the first in vivo longitudinal study showing that HRV is detected more frequently and persists for longer periods in CF patients compared with healthy controls. This might indicate increased viral replication and/or decreased antiviral defense in patients with CF.

Rhinovirus-associated pulmonary exacerbations show a lack of FEV1 improvement in children with cystic fibrosis

BACKGROUND

Respiratory viral infections lead to bronchial inflammation in patients with cystic fibrosis, especially during pulmonary exacerbations. The aim of this study was to determine the impact of viral-associated pulmonary exacerbations in children with cystic fibrosis and failure to improve forced expiratory volume in 1 s (FEV1 ) after an appropriate treatment.

METHODS

We lead a pilot study from January 2009 until March 2013. Children with a diagnosis of cystic fibrosis were longitudinally evaluated three times: at baseline (Visit 1), at the diagnosis of pulmonary exacerbation (Visit 2), and after exacerbation treatment (Visit 3). Nasal and bronchial samples were analyzed at each visit with multiplex viral respiratory PCR panel (qualitative detection of 16 viruses). Pulmonary function tests were recorded at each visit, in order to highlight a possible failure to improve them after treatment. Lack of improvement was defined by an increase in FEV1 less than 5% between Visit 2 and Visit 3.

RESULTS

Eighteen children were analyzed in the study. 10 patients failed to improve by more than 5% their FEV1 between Visit 2 and Visit 3. Rhinovirus infection at Visit 2 or Visit 3 was the only risk factor significantly associated with such a failure (OR, 12; 95% CI, 1·3-111·3), P = 0·03.

CONCLUSIONS

Rhinovirus infection seems to play a role in the FEV1 recovery after pulmonary exacerbation treatment in children with cystic fibrosis. Such an association needs to be confirmed by a large-scale study because this finding may have important implications for pulmonary exacerbation management.

Rhinovirus Load Is High despite Preserved Interferon-β Response in Cystic Fibrosis Bronchial Epithelial Cells

Lung disease in cystic fibrosis (CF) is often exacerbated following acute upper respiratory tract infections caused by the human rhinovirus (HRV). Pathophysiology of these exacerbations is presently unclear and may involve deficient innate antiviral or exaggerated inflammatory responses in CF airway epithelial cells. Furthermore, responses of CF cells to HRV may be adversely affected by pre-exposure to virulence factors of Pseudomonas (P.) aeruginosa, the microorganism that frequently colonizes CF airways. Here we examined production of antiviral cytokine interferon-β and inflammatory chemokine interleukin-8, expression of the interferon-responsive antiviral gene 2'-5'-oligoadenylate synthetase 1 (OAS1), and intracellular virus RNA load in primary CF (delF508 CFTR) and healthy airway epithelial cells following inoculation with HRV16. Parallel cells were exposed to virulence factors of P. aeruginosa prior to and during HRV16 inoculation. CF cells exhibited production of interferon-β and interleukin-8, and expression of OAS1 at levels comparable to those in healthy cells, yet significantly higher HRV16 RNA load during early hours post-inoculation with HRV16. In line with this, HRV16 RNA load was higher in the CFBE41o- dF cell line overexpessing delF508 CFTR, compared with the isogenic control CFBE41o- WT (wild-type CFTR). Pre-exposure to virulence factors of P. aeruginosa did not affect OAS1 expression or HRV16 RNA load, but potentiated interleukin-8 production. In conclusion, CF cells demonstrate elevated HRV RNA load despite preserved interferon-β and OAS1 responses. High HRV load in CF airway epithelial cells appears to be due to deficiencies manifesting early during HRV infection, and may not be related to interferon-β.