Search

Background: Although coronavirus disease 2019 (COVID‐19) is primarily a respiratory infection, mounting evidence suggests that the gastrointestinal tract is involved in the disease, with gut barrier dysfunction and gut microbiota alterations being related to disease severity. Whether these alterations persist and are related to long‐term respiratory dysfunction remains unknown. Methods: Plasma was collected during hospital admission and after 3 months from the NOR‐Solidarity trial (n = 181) and analyzed for markers of gut barrier dysfunction and inflammation. At the 3‐month follow‐up, pulmonary function was assessed by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO). Rectal swabs for gut microbiota analyses were collected (n = 97) and analyzed by sequencing the 16S rRNA gene. Results: Gut microbiota diversity was reduced in COVID‐19 patients with respiratory dysfunction, defined as DLCO below the lower limit of normal 3 months after hospitalization. These patients also had an altered global gut microbiota composition, with reduced relative abundance of 20 bacterial taxa and increased abundance of five taxa, including Veillonella, potentially linked to fibrosis. During hospitalization, increased plasma levels of lipopolysaccharide‐binding protein (LBP) were strongly associated with respiratory failure, defined as pO2/fiO2 (P/F ratio) <26.6 kPa. LBP levels remained elevated during and after hospitalization and were associated with low‐grade inflammation and respiratory dysfunction after 3 months. Conclusion: Respiratory dysfunction after COVID‐19 is associated with altered gut microbiota and persistently elevated LBP levels. Our results should be regarded as hypothesis generating, pointing to a potential gut–lung axis that should be further investigated in relation to long‐term pulmonary dysfunction and long COVID. [ABSTRACT FROM AUTHOR]

Background: Immune dysregulation is a major factor in the development of severe coronavirus disease 2019 (COVID-19). The homeostatic chemokines CCL19 and CCL21 have been implicated as mediators of tissue inflammation, but data on their regulation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is limited. We thus investigated the levels of these chemokines in COVID-19 patients., Methods: Serial blood samples were obtained from patients hospitalized with COVID-19 (n = 414). Circulating CCL19 and CCL21 levels during hospitalization and 3-month follow-up were analyzed. In vitro assays and analysis of RNAseq data from public repositories were performed to further explore possible regulatory mechanisms., Results: A consistent increase in circulating levels of CCL19 and CCL21 was observed, with high levels correlating with disease severity measures, including respiratory failure, need for intensive care, and 60-day all-cause mortality. High levels of CCL21 at admission were associated with persisting impairment of pulmonary function at the 3-month follow-up., Conclusions: Our findings highlight CCL19 and CCL21 as markers of immune dysregulation in COVID-19. This may reflect aberrant regulation triggered by tissue inflammation, as observed in other chronic inflammatory and autoimmune conditions. Determination of the source and regulation of these chemokines and their effects on lung tissue is warranted to further clarify their role in COVID-19., Clinical Trials Registration: NCT04321616 and NCT04381819., Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)