Type 1 interferons (IFN1) are both key molecules of antiviral defense and potent inflammatory mediators. In 2003, increased expression of a variety of interferon 1-regulated genes was observed in a blood cells of patients with systemic lupus erythematosus (SLE). This phenomenon was called the type 1 interferon signature (IFN1-signature). Since then, expression patterns indicating the presence of an IFN1-signature were consistently detected in a range of monogenic and complex autoimmune and autoinflammatory conditions. A quantitative indicator reflecting the degree of hyperactivation of the IFN1 pathway is known as interferon score. This review discusses the possible causes of upregulated expression of interferon 1-induced genes, the laboratory approaches to the interferon score analysis, as well as the practical use of this indicator for the diagnosis of various conditions.

BACKGROUND: There is no vaccine or specific antiviral treatment for HCoVs infection. The use of type I interferons for coronavirus is still under great debate in clinical practice.
METHODS: A literature search of all relevant studies published on PubMed, Cochrane library, Web of Science database, Science Direct, Wanfang Data, and China National Knowledge Infrastructure (CNKI) until February 2020 was performed.
RESULTS: Of the 1081 identified articles, only 15 studies were included in the final analysis. Comorbidities and delay in diagnosis were significantly associated with case mortality. Type I interferons seem to improve respiratory distress, relieve lung abnormalities, present better saturation, reduce needs for supplemental oxygen support. Type I interferons seem to be well tolerated, and don\'t increase life threating adverse effects. Data on IFNs in HCoVs are limited, heterogenous and mainly observational.
CONCLUSIONS: Current data do not allow making regarding robust commendations for the use of IFNs in HCoVs in general or in specific subtype. But we still recommend type I interferons serving as first-line antivirals in HCoVs infections within local protocols, and interferons may be adopted to the treatments of the SARS-CoV-2 as well. Well-designed large-scale prospective randomized control trials are greatly needed to provide more robust evidence on this topic.