In 2007, Benigni et al. described the presence of an intense and diffuse TLR9 staining in proximal tubules of class IV LN patients compared with controls, without any glomerular expression; moreover, both sera and purified ICs from SLE patients were able to increase significantly TLR9 mRNA expression in cultured tubular cells [5]. The gene discussed is TLR9; the disease is systemic lupus erythematosus.