TLR7 and systemic lupus erythematosus: PDCs were incubated in the presence of increasing concentrations of 24F4A or 24F4A-ef and stimulated with synthetic TLR7 ligand (R848), synthetic TLR9 ligand (CpG-A), or a disease-relevant ligand, SLE immune complexes (SLE-IC), Sm/RNP.