Systemic lupus erythematosus (SLE) is 9 times more prevalent in females than in males, suggesting a possible role for X-linked genes in disease onset and progression. Toll-like receptor (TLR7) is an X-encoded innate immune sensor that detects RNA degradation products to promote inflammatory cytokine and interferon production during viral infection. While aberrant TLR7 activity has long been implicated in the aetiology of systemic autoimmunity, a recent study published in Nature has now definitively linked gain-of-function mutations in TLR7 with human lupus [1]. There are currently no approved therapeutic inhibitors of TLR7, making this an urgent unmet need. We have developed novel synthetic, RNA-like trimeric oligonucleotides that bind to TLR7 with low nanomolar potency to effectively block its activation by RNA.