The roles played by hsa-miR-223-5p and mutations in the S gene of SARS-CoV-2 in COVID-19.

Background: Increased proinflammatory molecules are a main reason for severe symptoms in patients infected with SARS-CoV-2. This study evaluated mutations in the S gene of SARS-CoV-2 and the expression of hsa-miR-223-5p, interleukin 2 receptor α (IL-2Rα), and CCL16 chemokine in hospitalized SARS-CoV-2 infected patients.

Design: This is a cross-sectional study.

Methods: This study included 75 SARS-CoV-2-infected patients with severe symptoms and 75 age-sex-matched healthy controls. Real-time polymerase chain reaction techniques were used to evaluate the expression levels of hsa-miR-223-5p, IL-2Rα, and CCL16 chemokine. The Sanger technique was used to sequence the S gene of SARS-CoV-2 from positions 23,274 to 23,641.

Results: The relative expression of hsa-miR-223-5p was significantly increased whereas that of IL-2Rα was significantly decreased in the SARS-CoV-2 infected patients. Two mutations were found in the S gene of SARS-CoV-2 at positions 23,403 (p.Asp23403Gly) and 23,525 (p.His23525Tyr) of the S gene of SARS-CoV-2.

Conclusion: Increased hsa-miR-223-5p may be a main cause for the downregulation of IL-2Rα, which is a main developer of T-regulatory lymphocytes. The mutations in the S gene of SARS-CoV-2-infected patients may affect immune responses to the molecule and alter the avidity of virus-human cell interactions.