Systemic Multi-Omics Analysis Reveals Interferon Response Heterogeneity and Links Lipid Metabolism to Immune Alterations in Severe COVID-19
The immune response to SARS-CoV-2 infection is highly heterogeneous, and interferon (IFN)-stimulated genes (ISGs) play a central but context-dependent role in antiviral defense and immune dysregulation. To investigate how ISG heterogeneity relates to immune and metabolic states, we performed an integrated analysis of whole-blood transcriptomics, plasma proteomics, metabolomics, and immune activation markers in hospitalized COVID-19 patients and COVID-negative healthy controls and covalescent individuals. Patients segregated into low (LIS), moderate (MIS), and high (HIS) ISG expression endotypes, largely independent of clinical severity. While high ISG expression was associated with systemic inflammation and innate immune activation, severe disease within the HIS endotype was characterized by marked metabolic perturbations, including depletion of tricarboxylic acid cycle intermediates and multiple lipid classes involved in membrane integrity and immunometabolic signaling. Plasma-transfer assays demonstrated that plasma from severe HIS patients impaired neutrophil and monocyte activation ex vivo, indicating functional attenuation of innate immune responses despite elevated ISG expression. These metabolic alterations correlated with reduced immune activation, supporting the existence of an interferon-associated immune-metabolic axis that constrains immune functionality in severe disease. Although type I IFN neutralization was detected in a subset of patients with IFN antigen reactivity, these samples did not account for ISG heterogeneity or disease severity. Together, these findings show that high ISG expression defines a transcriptional endotype permissive for inflammation but insufficient for effective immune function, highlighting the importance of immune-metabolic context in shaping COVID-19 disease outcomes.