TLR7 and systemic lupus erythematosus: The results also showed that such differential regulation of TLR7/9 response in pDCs of SLE patients was due to the priming effects of type I and type II IFNs; namely, TLR7-mediated IFN-α production was up-regulated by pre-treatment with type I IFN and TLR9-mediated IFN-α production was down-regulated by pre-treatment with type II IFN.