IFNA1 and systemic lupus erythematosus: Interestingly, even though SLE keratinocytes are hyperresponsive to IFNa2 (24), the expression of TRIM21α/Ro52α and TRIM21δ/Ro52δ was not different in SLE compared with healthy control keratinocytes either at baseline or after IFN stimulation (Supplemental Figure 2).