TLR7 and systemic lupus erythematosus: Interestingly, upon infection, HPV further down-regulates TLR7 and TLR9 levels in lupus patients, which is consistent with previous reports showing that oncogenic HPV16 may suppress the host immune response by down-regulating the TLR9 transcript and, subsequently, limit its ability to induce the transcription of pro-inflammatory genes for antiviral immune responses [23].