TLR9 and systemic lupus erythematosus: In particular, immune complexes containing the lupus autoantigen U1snRNP or nucleosomes activate DCs and autoreactive B-cells via TLR7 and TLR9, respectively, contributing in this way to pathogenesis of systemic lupus erythematosus (Leadbetter et al., 2002; Marshak-Rothstein and Rifkin, 2007).