In cystic fibrosis (CF), Pseudomonas aeruginosa (Pa) colonizes the lungs, leading to chronic inflammation of the bronchial epithelium. ChaC glutathione specific γ glutamylcyclotransferase 1 (CHAC1) mRNA is differentially expressed in primary human airway epithelial cells from bronchi (hAECBs) from patients with CF and healthy patients at baseline and upon infection with Pa. CHAC1 degrades glutathione and is associated with ER stress and apoptosis pathways. In this study, we examined the roles of CHAC1 in the inflammatory response and apoptosis in lung epithelial cells. First, we confirmed by reverse transcription quantitative polymerase chain reaction that CHAC1 mRNA was overexpressed in hAECBs from patients without CF compared with the expression in hAECBs from patients with CF upon Pa (PAK strain) infection. Moreover, the Pa virulence factors LPS and flagellin (F) were shown to induce CHAC1 expression in cells from patients without CF. Using NCI H292 lung epithelial cells, we found that LPS induced CHAC1 mRNA expression was PERK independent and involved ATF4. Additionally, using CHAC1 small interfering RNA, we showed that reduced CHAC1 expression in the context of LPS and F stimulation was associated with modulation of inflammatory markers and alteration of NF-κB signaling. Finally, we showed that Pa was not able to induce apoptosis in NCI H292 cells. Our results suggest that CHAC1 is involved in the regulation of inflammation in bronchial cells during Pa infection and may explain the excessive inflammation present in the respiratory tracts of patients with CF.

Over two years (2012–2014), 719 nasopharyngeal samples were collected from 6-week- to 12-month-old infants presenting at the emergency department with moderate to severe acute bronchiolitis. Viral testing was performed, and we found that 98% of samples were positive, including 90% for respiratory syncytial virus, 34% for human rhino virus, and 55% for viral co-detections, with a predominance of RSV/HRV co-infections (30%). Interestingly, we found that the risk of being infected by HRV is higher in the absence of RSV, suggesting interferences or exclusion mechanisms between these two viruses. Conversely, coronavirus infection had no impact on the likelihood of co-infection involving HRV and RSV. Bronchiolitis is the leading cause of hospitalizations in infants before 12 months of age, and many questions about its role in later chronic respiratory diseases (asthma and chronic obstructive pulmonary disease) exist. The role of virus detection and the burden of viral codetections need to be further explored, in order to understand the physiopathology of chronic respiratory diseases, a major public health issue.

Introduction: Acute respiratory infections (ARI) are the most common infections in the general population and are mainly caused by respiratory viruses. Detecting several viruses in a respiratory sample is common. To better understand these viral codetections and potential interferences, we tested for the presence of viruses and developed quantitative PCR (Polymerase Chain Reaction) for the viruses most prevalent in coinfections: human rhinovirus (HRV) and respiratory syncytial virus (RSV), and quantified their viral loads according to coinfections and health status, age, cellular abundance and other variables.Materials and methods: Samples from two different cohorts were analyzed: one included hospitalized infants under 12 months of age with acute bronchiolitis (n=719) and the other primary care patients of all ages with symptoms of ARI (n=685). We performed Multiplex PCR on nasopharyngeal swabs, and quantitative PCR on samples positive for HRV or/and RSV to determine viral loads (VL). Cellular abundance (CA) was also estimated by qPCR targeting the GAPDH gene. Genotyping was performed either directly from first-line molecular panel or by PCR and sequencing for HRV.Results: The risks of viral codetection were 4.1 (IC₉₅[1.8; 10.0]) and 93.9 1 (IC₉₅[48.7; 190.7]) higher in infants hospitalized for bronchiolitis than in infants in primary care for RSV and HRV respectively (p<0.001). CA was higher in samples positive for multiple viruses than in mono-infected or negative samples (p<0.001), and higher in samples positive for RSV (p<0.001) and HRV (p<0.001) than in negative samples. We found a positive correlation between CA and VL for both RSV and HRV. HRV VL was higher in children than in the elderly (p<0.05), but not RSV VL. HRV VL was higher when detected alone than in samples coinfected with RSV-A and with RSV-B. There was a significant increase of RSV-A VL when codetecting with HRV (p=0.001) and when co-detecting with RSV-B+HRV versus RSV-A+ RSV-B (p=0.02).Conclusions: Many parameters influence the natural history of respiratory viral infections, and quantifying respiratory viral loads can help disentangle their contributions to viral outcome.

Introduction: Acute respiratory infections (ARIs) are the most common viral infections encountered in primary care settings. The identification of causal viruses is still not available in routine practice. Although new strategies of prevention are being identified, knowledge of the relationships between respiratory viruses remains limited.Materials and methods: ECOVIR was a multicentric prospective study in primary care, which took place during two pre-pandemic seasons (2018–2019 and 2019–2020). Patients presenting to their General practitioner (GP) with ARIs were included, without selecting for age or clinical conditions. Viruses were detected on nasal swab samples using a multiplex Polymerase Chain Reaction test focused on 17 viruses [Respiratory Syncytial Virus-A (RSV-A), RSV-B, Rhinovirus/Enterovirus (HRV), human Metapneumovirus (hMPV), Adenovirus (ADV), Coronaviruses (CoV) HKU1, NL63, 229E, OC43, Influenza virus (H1 and H3 subtypes), Influenza virus B, Para-Influenza viruses (PIVs) 1–4, and Bocavirus (BoV)].Results: Among the 668 analyzed samples, 66% were positive for at least one virus, of which 7.9% were viral codetections. The viral detection was negatively associated with the age of patients. BoV, ADV, and HRV occurred more significantly in younger patients than the other viruses (p < 0.05). Codetections were significantly associated with RSV, HRV, BoV, hMPV, and ADV and not associated with influenza viruses, CoV, and PIVs. HRV and influenza viruses were negatively associated with all the viruses. Conversely, a positive association was found between ADV and BoV and between PIVs and BoV.Conclusion: Our study provides additional information on the relationships between respiratory viruses, which remains limited in primary care.

Acute respiratory infections (ARI) are the most common infections in the general population and represent an important socio-economic burden. Characterizing ARIs in primary care in patients of all ages in terms of clinical presentation, and virological results. We conducted a prospective multicenter study in primary care: 36 French general practitioners (GPs) included patients from all ages presenting with symptoms of ARI, and performed a nasopharyngeal swab, which was analyzed by Multiplex RT-PCR. 685 patients of all ages were included in the cohort. We found associations between clinical diagnosis and respiratory viruses: influenza was associated with the diagnosis of flu-like syndrome (p < 0.001), HRV with rhinitis (p < 0.05), and RSV with bronchiolitis (p < 0.001) and bronchitis (p < 0.05). Respiratory distress was associated with RSV (p = 0.002), and a cough at the inclusion was significantly not associated with the influenza virus (p = 0.009). Antibiotic prescriptions were not associated with any specific virus. By day 7, persistent cough was significantly associated with active and passive smoking (respectively p = 0.01 and p < 0.001), influenza and RSV-positive samples (p < 0.05) and an age of less than 2 years (p < 0.01). With this prospective cohort performed in primary care including patients of all ages, we characterized viral respiratory infections, to better understand correlations between clinical data and virological results.