TLR9 and systemic lupus erythematosus: Exosomes derived from lymphocytic leukemia (CLL) can target TLR7 signaling to promote innate immunity [75], while exosomes isolated from systemic lupus erythematosus (SLE) patients' serum can produce abundant IFN-α, TNF-α, IL-1β, and IL-6 via the TLR1/2, TLR7, TLR9, and TLR4 pathways [76].