Abstract
OBJECTIVE: Type I interferons (IFN) have important roles in many immune-mediated inflammatory diseases (IMIDs) and are a relatively new therapeutic target. Direct detection of type I IFNs has proved challenging, thus their presence is often inferred from the expression of interferon-stimulated genes (ISGs) and calculation of an interferon score (IS). The objective of this research was to determine if the expression of six common ISGs and subsequent IS were comparable when RNA was derived from the Tempus and PAXgene whole blood RNA collection systems. RESULTS: Whole blood was obtained from ten healthy adults, incubated ex vivo in the absence and presence of recombinant human IFNα then divided into PAXgene and Tempus tubes. Despite reports of tube-specific patterns of gene expression, quantitative PCR (qPCR) analysis revealed no significant differences between PAXgene and Tempus tubes in either the homeostatic or IFNα-induced expression of six ISGs (IFI27, IFI44L, IFIT1, ISG15, RSAD2, SIGLEC1). Overall there was a strong correlation in the IS between unstimulated (r = 0.92, p = 0.0005) and IFNα-stimulated (r = 0.71, p = 0.0268) samples derived from the PAXgene and Tempus tubes.