The levels of IFN-α produced by SLE peripheral blood mononuclear cells (PBMCs) induced by SLE serum that contained an endogenous IFN-α-inducing factor, herpes simplex virus type 1, or the D type of CpG motif were lower than those produced by healthy control PBMCs, and the IFN-α producing capability of circulating pDCs in SLE patients may be impaired [16-18]. This evidence concerns the gene IFNA1 and systemic lupus erythematosus.