Type I interferon modulation of cellular responses to cytokines and infectious pathogens: potential role in SLE pathogenesis.

Type I interferons (IFNs) are pleiotropic cytokines that have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). A key aspect of type I IFN biology is that previous exposure to type I IFNs alters subsequent cellular responses to extracellular stimuli. Type I IFNs may either prime cells for stronger responses to viruses, bacterial pathogens and cytokines such as IL-6 and IFN-gamma, or may suppress cellular responses to LPS and TNFalpha. Herein, we review type I IFN signal transduction via the Jak-STAT pathway, and mechanisms by which type I IFNs prime or suppress responses to environmental factors. We develop a hypothesis that type I IFN-dependent priming/enhancement of cellular responses to pro-inflammatory cytokines such as IFNgamma and IL-6 contributes to pathogenesis of SLE. In addition, cross-regulation between type I IFNs and TNFalpha and its potential role in SLE pathogenesis is discussed.