Figure 1. Mechanisms of action of type 1 interferon-linked monoclonal antibodies. The type 1 interferon (IFN-I) receptor (IFNAR) comprises the 2 subunits IFNAR1 and IFNAR2. Upon activation, intracellular receptor-linked kinases initiate phosphorylation and coupling of specific proteins, subsequently translocating to the nucleus. Here, they activate the expression of INF-stimulated genes, which mediate the antiviral effector functions of IFN-I. Anifrolumab (underlined red) targets IFNAR1, thereby preventing IFN-I (here illustrated with IFN-α and IFN-β) from activating IFNAR. Sifalimumab and rontalizumab selectively bind to IFN-α, allowing the other cytokine members of the IFN-I family (such as IFN-β) to still activate IFNAR.Created with BioRender.com.