Potential Implications of a Type 1 Interferon Gene Signature on COVID-19 Severity and Chronic Inflammation in Sickle Cell Disease

Abstract

Graphical AbstractHypothesis: Baseline type I interferon activity may contribute to variable COVID-19 progression in SCD. (Top) At early stages of SARS-CoV-2 infection, high baseline IFNα/β activity may contribute to the anti-viral response in patients with SCD. Recognition of damage-associated molecular patterns by pattern recognition receptors (PRRs) induces IFNα/β production. Heme released from hemolyzed sickle cells binds Toll-like receptor 4 (TLR4), which may induce IFNα/β in vascular endothelial cells. IFNα/β bind to the IFNα/β receptor (IFNAR) in neutrophils and other cells types, leading to production of MxA and other interferon-stimulated genes (ISGs). ISGs can directly inhibit viral replication and promote B cell production of neutralizing antibodies. The IFNα/β response is one of multiple responses, including production of IL-6, TNFα, and IL-1b, by innate and adaptive immune cells that have the potential to limit COVID-19 progression. (Bottom) In contrast, reduced or absent IFNα/β activity may increase susceptibility to viral infection, leading to airway epithelial cell death and COVID-19. Dashed lines indicate potentially connected pathways, while solid lines are supported by prior studies.