Are patients with lung cystic fibrosis at increased risk of severe and fatal COVID-19? Interleukin 6 as a predictor of COVID-19 outcomes

Assessment of COVID-19 risk factors of early and long-term mortality with prediction models of clinical and laboratory variables

BACKGROUND

Coronavirus disease (COVID-19) may lead to serious complications and increased mortality. The outcomes of patients who survive the early disease period are burdened with persistent long-term symptoms and increased long-term morbidity and mortality. The aim of our study was to determine which baseline parameters may provide the best prediction of early and long-term outcomes.

METHODS

The study group comprised 141 patients hospitalized for COVID-19. Demographic data, clinical data and laboratory parameters were collected. The main study endpoints were defined as in-hospital mortality and 1-year mortality. The associations between the baseline data and the study endpoints were evaluated. Prediction models were created.

RESULTS

The in-hospital mortality rate was 20.5% (n = 29). Compared with survivors, nonsurvivors were significantly older (p = 0.001) and presented comorbidities, including diabetes (0.027) and atrial fibrillation (p = 0.006). Assessment of baseline laboratory markers and time to early death revealed negative correlations between time to early death and higher IL-6 levels (p = 0.032; Spearman rho - 0.398) and lower lymphocyte counts (p = 0.018; Pearson r -0.438). The one-year mortality rate was 35.5% (n = 50). The 1-year nonsurvivor subgroup was older (p < 0.001) and had more patients with arterial hypertension (p = 0.009), diabetes (p = 0.023), atrial fibrillation (p = 0.046) and active malignancy (p = 0.024) than did the survivor subgroup. The model composed of diabetes and atrial fibrillation and IL-6 with lymphocyte count revealed the highest value for 1-year mortality risk prediction.

CONCLUSIONS

Diabetes and atrial fibrillation, as clinical factors, and LDH, IL-6 and lymphocyte count, as laboratory determinants, are the best predictors of COVID-19 mortality risk.

Crosslink between SARS-CoV-2 replication and cystic fibrosis hallmarks

SARS-CoV-2, the etiological cause of the COVID-19 pandemic, can cause severe illness in certain at-risk populations, including people with cystic fibrosis (pwCF). Nevertheless, several studies indicated that pwCF do not have higher risks of SARS-CoV-2 infection nor do they demonstrate worse clinical outcomes than those of the general population. Recent in vitro studies indicate cellular and molecular processes to be significant drivers in pwCF lower infection rates and milder symptoms than expected in cases of SARS-CoV-2 infection. These range from cytokine releases to biochemical alterations leading to morphological rearrangements inside the cells associated with CFTR impairment. Based on available data, the reported low incidence of SARS-CoV-2 infection among pwCF is likely a result of several variables linked to CFTR dysfunction, such as thick mucus, IL-6 reduction, altered ACE2 and TMPRSS2 processing and/or functioning, defective anions exchange, and autophagosome formation. An extensive analysis of the relation between SARS-CoV-2 infection and pwCF is essential to elucidate the mechanisms involved in this lower-than-expected infection impact and to possibly suggest potential new antiviral strategies.

COVID-19 in patients with chronic lung disease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that causes an acute respiratory tract infection known as coronavirus disease 2019 (COVID-19). SARS-CoV-2 enters cells by binding the ACE2 receptor and coreceptors notably TMPRSS2 or Cathepsin L. Severe COVID-19 infection can lead to acute lung injury. Below we describe the current evidence of the impact of common chronic lung diseases (CLDs) on the development of COVID-19. The impact of treatment of CLD on COVID-19 and any risk of vaccination in patients with CLD are considered.

Chronic bacterial pulmonary infections in advanced cystic fibrosis differently affect the level of sputum neutrophil elastase, IL-8 and IL-6

Advanced cystic fibrosis (CF) lung disease is commonly characterized by a chronic Pseudomonas aeruginosa infection and destructive inflammation caused by neutrophils. However, the lack of convincing evidence from most informative biomarkers of severe lung dysfunction (SLD-CF) has hampered the formulation of a conclusive, targeted diagnosis of CF. The aim of this study was to determine whether SLD-CF is related to the high concentration of sputum inflammatory mediators and the presence of biofilm-forming bacterial strains. Forty-one patients with advanced CF lung disease were studied. The severity of pulmonary dysfunction was defined by forced expiratory volume in 1 second (FEV1) < 40%. C-reactive protein (CRP) and NLR (neutrophil-lymphocyte ratio) were examined as representative blood-based markers of inflammation. Expectorated sputum was collected and analysed for cytokines and neutrophil-derived defence proteins. Isolated sputum bacteria were identified and their biofilm-forming capacity was determined. There was no association between FEV1% and total number of sputum bacteria. However, in the high biofilm-forming group the median FEV1 was < 40%. Importantly, high density of sputum bacteria was associated with increased concentrations of neutrophil elastase and interleukin (IL)-8 and low concentrations of IL-6 and IL-10. The low concentration of sputum IL-6 is unique for CF and distinct from that observed in other chronic pulmonary inflammatory diseases. These findings strongly suggest that expectorated sputum is an informative source of pulmonary biomarkers representative for advanced CF and may replace more invasive bronchoalveolar lavage analysis to monitor the disease. We recommend to use of the following inflammatory biomarkers: blood CRP, NLR and sputum elastase, IL-6, IL-8 and IL-10.

Systematic review: cystic fibrosis in the SARS-CoV-2/COVID-19 pandemic

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the development of life-threatening COVID-19 are believed to disproportionately affect certain at-risk populations. However, it is not clear whether individuals with cystic fibrosis (CF) are at a higher risk of COVID-19 or its adverse consequences. Recurrent respiratory viral infections are often associated with perturbation and pulmonary exacerbations of CF as evidenced by the significant morbidity observed in CF individuals during the 2009 H1N1 pandemic. The primary goal of this review was to systematically survey published accounts of COVID-19 in CF and determine if individuals with CF are disproportionally affected by SARS-CoV-2 and development of COVID-19.

Methods

We conducted a systematic literature search using EMBASE and Medline between April 28 and December 10, 2020. Six evaluable studies reporting on a total of 339 individuals with CF who developed COVID-19 were included in this study.

Results

We found that although individuals with CF generally experience acute exacerbations of lung disease from infectious agents, COVID-19 incidence estimates in CF appear to be lower than in the general population. However, there are reports of subsets of CF, such as those who had organ transplants, that may experience a more severe COVID-19 course. Potential protective mechanisms in the CF population include pre-pandemic social isolation practices, infection prevention and control knowledge, altered expression of angiotensin-converting enzyme, and the use of certain medications.

Conclusions

Although individuals with CF are at risk of acute exacerbations often precipitated by respiratory tract viral infections, published evidence to date indicated that individuals with CF do not experience higher risks of contracting SARS-CoV-2 infection. However, there is evidence that some subsets within the CF population, including those post-transplantation, may experience a more severe clinical course. As SARS-CoV-2 variants are identified and the pandemic goes through additional waves of disease outbreaks, ongoing monitoring of the risk of COVID-19 in individuals with CF is required.

The dual role of the immune system in the course of COVID-19. The fatal impact of the aging immune system

COVID-19 is a highly contagious respiratory disease caused by the novel coronavirus SARS-CoV-2. Since October 2020 the second wave of the pandemic has been observed around the world, as pathogen specific herd immunity has not been built yet. Moreover, the current, more contagious pathogen carrying the D614G mutation has become the globally dominant form of SARS-CoV-2. In this article we present the current state of knowledge on the impact of ACE2 and the reninangiotensin system (RAS) and the innate immune system on different outcomes of COVID-19. Especially, we point out the dual role of the immune system and ACE2 in pathogenesis of the disease. Namely, at the initial stage of the infection anti-viral activity of innate immunity is responsible for inhibition of SARS-CoV-2 replication. On the other hand, a dysregulated immune response may cause the detrimental hyperinflammation ("cytokine storm") responsible for the severe course of the disease. Concomitantly, we analyse the roles of ACE2 in both facilitation of infection and abrogation of its effects, as the major cellular entry receptor for SARS-CoV-2 and an important enzyme responsible for tissue protection, respectively. Finally, we discuss the dominant impact of aging on the fatal outcome of COVID-19.