Viral respiratory tract infections in young children with cystic fibrosis: a prospective full-year seasonal study

Respiratory Viruses and Cystic Fibrosis

The threat of respiratory virus infection to human health and well-being has been clearly highlighted by the coronavirus disease 2019 (COVID-19) pandemic. For people with cystic fibrosis (CF), the clinical significance of viral infections long predated the emergence of severe acute respiratory syndrome coronavirus 2. This article reviews the epidemiology, diagnosis, and treatment of respiratory virus infection in the context of CF as well as the current understanding of interactions between viruses and other microorganisms in the CF lung. The incidence of respiratory virus infection in CF varies by age with young children typically experiencing more frequent episodes than adolescents and adults. At all ages, respiratory viruses are very common in CF and are associated with pulmonary exacerbations. Respiratory viruses are identified at up to 69% of exacerbations, while viruses are also frequently detected during clinical stability. The full impact of COVID-19 in CF is yet to be established. Early studies found that rates of COVID-19 were lower in CF cohorts than in the general population. The reasons for this are unclear but may be related to the effects of shielding, infection control practices, maintenance CF therapies, or the inflammatory milieu in the CF lung. Observational studies have consistently identified that prior solid organ transplantation is a key risk factor for poor outcomes from COVID-19 in CF. Several key priorities for future research are highlighted. First, the impact of highly effective CFTR modulator therapy on the epidemiology and pathophysiology of viral infections in CF requires investigation. Second, the impact of respiratory viruses on the development and dynamics of the CF lung microbiota is poorly understood and viral infection may have important interactions with bacteria and fungi in the airway. Finally, bacteriophages represent a key focus of future investigation both for their role in transmission of antimicrobial resistance and as a promising treatment modality for multiresistant pathogens.

Incidence, prevalence, clinical features, and outcomes of COVID-19 in persons with cystic fibrosis: a systematic review protocol

OBJECTIVE

The objective of this review is to determine the incidence and prevalence, clinical features, and outcomes of COVID-19 in persons with cystic fibrosis.

INTRODUCTION

Cystic fibrosis, predominantly a chronic respiratory illness, has long been known to be fatal with concomitant bacterial or viral infections. Consequently, the effects of COVID-19 on this protracted disease need to be understood, especially since the major manifestations affect the respiratory system. Hence, this review aims to examine the burden, clinical features, and outcomes of COVID-19 on individuals with cystic fibrosis.

INCLUSION CRITERIA

This review will consider studies of persons in all age groups with preexisting cystic fibrosis who are diagnosed with COVID-19 using either a polymerase chain reaction, serology, or point-of-care test for SARS-CoV-2. Eligible studies will report the incidence, prevalence, clinical features, or outcomes of COVID-19 in individuals with cystic fibrosis. Studies in community or health care settings from any geographic location will be considered.

METHODS

The JBI methodology for systematic reviews of prevalence and incidence will be used for this review. A methodical search for eligible studies in English (as well as available translations) in MEDLINE, Embase, Scopus, and CINAHL, and unpublished literature in Google Scholar, Dissertation Abstracts International, ProQuest Dissertations and Theses, and MedNar will be conducted from the year 2020 onwards. Studies meeting the inclusion criteria will be selected for appraisal and their methodological quality will be assessed by two independent reviewers based on study titles and abstracts, followed by full-text review focusing on sampling and statistical analysis. Data extraction will be accomplished using a standardized tool. If adequate synthesized data are obtained, a meta-analysis will be conducted; otherwise, the findings will be presented in narrative format, including tables and figures to aid in data presentation.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42021237792.

Coxsackievirus B infections are common in Cystic Fibrosis and experimental evidence supports protection by vaccination

Viral respiratory tract infections exacerbate airway disease and facilitate life-threatening bacterial colonization in cystic fibrosis (CF). Annual influenza vaccination is recommended and vaccines against other common respiratory viruses may further reduce pulmonary morbidity risk. Enteroviruses have been found in nasopharyngeal samples from CF patients experiencing pulmonary exacerbations. Using serology tests, we found that infections by a group of enteroviruses, Coxsackievirus Bs (CVBs), are prevalent in CF. We next showed that a CVB vaccine, currently undergoing clinical development, prevents infection and CVB-instigated lung damage in a murine model of CF. Finally, we demonstrate that individuals with CF have normal vaccine responses to a similar, commonly used enterovirus vaccine (inactivated poliovirus vaccine). Our study demonstrates that CVB infections are common in CF and provides experimental evidence indicating that CVB vaccines could be efficacious in the CF population. The role of CVB infections in contributing to pulmonary exacerbations in CF should be further studied.

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CVB infections are common in CF

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A CVB vaccine prevents infection and tissue damage in a model of CF

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Most people with CF have robust antibody responses to a similar enterovirus vaccine

High prevalence of Merkel cell polyomavirus is associated with dysregulation in transcript levels of TLR9 and type I IFNs in a large cohort of CF patients from the Italian (Lazio) reference center for cystic fibrosis

Merkel cell polyomavirus (MCPyV) has been detected in respiratory specimens including those from Cystic Fibrosis (CF) patients, raising questions about its immunological and clinical relevance in the respiratory tract. MCPyV might promote an inappropriate antiviral response contributing to a chronic inflammatory response and resulting in detrimental effects in CF. Respiratory samples (n = 1138) were randomly collected from respiratory tract of CF patients (n = 539) during July 2018-October 2019. MCPyV-DNA detection was performed by Real Time-PCR and positive samples were characterized by sequencing of the NCCR genomic region. The transcript levels of Toll-like receptor 9 (TLR9) and type I interferon (IFN-I) genes (IFNα, IFNβ and IFNε) were examined by RT/Real Time-PCR assays. MCPyV-DNA was detected in 268 out of 1138 respiratory specimens (23.5%) without any difference in the prevalence of MCPyV-DNA according to age, gender or bacteriological status of CF individuals. Thirteen out of 137 CF patients remained positive for MCPyV-DNA over the time (a median follow-up period of 8.8 months). Detection of MCPyV-DNA in respiratory specimens was not associated with the occurrence of exacerbation events. Both MCPyV positive adolescents (11-24 years) and adults (>25 years) had lower mRNA levels of TLR9, IFNβ, IFNε and IFNα than the negative patients of the same age group, while MCPyV positive children produced increased levels of TLR9 and IFN-I genes (p < 0.05 for TLR9, IFNβ, IFNε) with respect to the negative ones. There were significant differences in TLR9 levels (p < 0.01), but not in those of IFNs, between MCPyV-DNA positive and negative patients with S. aureus, P. aeruginosa or both. Overall, these results indicate that MCPyV-DNA is frequently detected in the respiratory samples of CF patients and might influence the expression levels of IFN-related genes in an age dependent manner. The concomitant detection of MCPyV together with S. aureus and/or P. aeruginosa correlated with alterations in TLR9 levels suggesting that virus-bacteria coinfections might contribute to affect antiviral immunity in CF patients.

Research advances in molecular mechanisms underlying the pathogenesis of cystic fibrosis: From technical improvement to clinical applications (Review)

Cystic fibrosis (CF) is a chronic disease causing severe impairment to the respiratory system and digestive tracts. Currently, CF is incurable. As an autosomal recessive disorder, the morbidity of CF is significantly higher among Caucasians of European descent, whereas it is less pervasive among African and Asian populations. The disease is caused by identical mutations (homozygosity) or different mutations (heterozygosity) of an autosomal recessive mutation at position 7q31.2-q31.1 of chromosome 7. Diagnostic criteria and guidelines work concurrently with laboratory detection to facilitate precise CF detection. With technological advances, the understanding of CF pathogenesis has reached an unprecedented level, allowing for increasingly precise carrier screening, more effective early stage CF intervention and improved prognostic outcomes. These advances significantly increase the life quality and expectancy of patients with CF. Given the numerous improvements in the field of CF, the current review summarized the technical advances in the study of the molecular mechanisms underlying CF, as well as how these improvements facilitate the clinical outcomes of CF. Furthermore, challenges and obstacles to overcome are discussed.

COVID-19 and Cystic Fibrosis: Diagnostic Difficulties or Incorrect Methods?

Cystic fibrosis (CF) is a chronic lung disease with wide distribution worldwide. With the appearance of the Coronavirus Disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), difficulties arise when evaluating, diagnosing, and treating patients with other conditions, including CF. We present the case of a patient with CF who had a definite serological diagnosis, a CT scan suggestive of SARS-CoV-2 infection/COVID-19, and a negative molecular test (RT-PCR), with rapid resolution of symptoms and early discharge. CF/SARS-CoV-2 comorbidity needs to be adequately studied and assessed in the context of the COVID-19 pandemic.