PRJNA707223: Peripheral blood gene expression according to IFIH1 rs1990760 variants in critically-ill COVID-19 patients

Summary: Peripheral blood gene expression according to IFIH1 rs1990760 variants in critically-ill COVID-19 patients

Overall Design: Background: Outcomes in patients with severe SARS-CoV-2 infection (COVID-19) are conditioned by viral control and regulation of inflammation. Variants in IFIH1, a gene coding the cytoplasmatic RNA sensor MDA5, regulate the response to viral infections. Methods: Patients admitted to an intensive care unit (ICU) with documented COVID-19 were prospectively included and IFIH1 rs1990760 genotypes determined. Peripheral blood gene expression, cell populations and immune mediators were measured during the first day after ICU admission before steroid therapy. Peripheral blood mononuclear cells from healthy volunteers were exposed ex-vivo to an MDA5 agonist and dexamethasone, and changes in gene expression assessed. ICU discharge and hospital death were modelled using rs1990760 variants and dexamethasone therapy as factors. Findings: 237 patients were studied. Patients with the IFIH1 rs1990760 TT variant showed a decrease in expression of inflammation-related pathways, an anti-inflammatory cell profile and a decrease in pro-inflammatory mediators. Cells with TT variant exposed to an MDA5 agonist ex-vivo showed an increase in FOXO3 and IL6 when dexamethasone was added. All patients with the TT variant not treated with steroids (n=14) survived their ICU stay (HR 2.49 95% confidence interval 1.29 – 4.79). Dexamethasone therapy in this subgroup (N=50) delayed ICU discharge and increased hospital mortality (HR 2.19, 95% confidence interval 1.01 – 4.87) and serum IL-6 concentrations. Interpretation: COVID-19 ICU patients with the IFIH1 rs1990760 TT variant show an ameliorated inflammatory response that results in better outcomes than CC/CT variants. Dexamethasone can reverse this anti-inflammatory phenotype, worsening the outcome. Funding: Instituto de Salud Carlos III.