Table 5.

Interferon response to SARS-CoV-2 infection

Author	Study type	Patients N	Control N	Populations	Cells	RoB
Hadjadj et al48	CyTOF Simoa immunoassay RT-qPCR PBMCs	50 (15 mild to moderate, 17 severe and 18 critical patients	HD 18	COVID-19 (mild, moderate and/or severe) vs HD	↓↓↓ IFN-β mRNA and protein	Low
				Severe COVID-19 vs HD	↑genes involved in type I IFN signalling (such as IFNAR1, JAK1 and TYK2) ↓ IFN-stimulated genes (such as MX1, IFITM1 and IFIT2)
				Severe COVID-19 vs mild/moderate	↓↓ plasma levels of IFN-α2 protein and IFN activity significantly Lower type I IFN response in severe vs critical patients
Zhu et al46	Multiparametric flow cytometry Patients’ DC cultures	Acute COVID-19 (6 severe and 11 mild) Convalescent COVID-19 (2 severe and 22 mild)	HD	COVID-19 (mild, moderate and/or severe) vs HD,	After stimulation: IFN-α was not induced in 3/3 active patients and 3/4 convalescent patients IFN-β was not increased in 3/3 active patients, rather only slightly elevated in 3/4 convalescent patients indicating a reduced capacity of making antiviral interferon	High

HD, healthy donor; IFN, interferon; JAK, Janus kinase; MCP, monocyte chemoattractant protein; TYK, tyrosine kinase.