Abstract: Antagonistic small-molecule compounds having a function of inhibiting endosomal Toll-like receptors (TLRs), more specifically, a small-molecule compound for inhibiting TLR3/7/8/9 signaling pathways, a composition for inhibiting Toll-like receptors, containing the compound; and a composition for preventing or treating autoimmune diseases, inflammatory diseases, or viral diseases are disclosed. The novel compound shows very significant results in a systemic lupus erythematosus animal model by not only preventing TNF-? secretion induced by poly I:C (TLR3 agonist), imiquimod (TLR7 agonist), TL8-506 (TLR8 agonist), or ODN2395 (TLR9 agonist), but also inhibiting the production of inflammatory cytokines. This suggests that the compound is also useful for the prevention or treatment of TLR3, TLR7, TLR8 or TLR9-associated autoimmune diseases, inflammatory diseases and viral diseases.

Abstract: A method of diagnosing systemic lupus erythematosus using an antigen protein that binds specifically to an SMYD3 autoantibody present in body fluid of a patient with systemic lupus erythematosus. The diagnostic method uses a non-invasive biological sample such as blood, and thus may diagnose systemic lupus erythematosus very conveniently without burdening the patient, unlike conventional methods. In addition, the method has high specificity and sensitivity, and thus may be effectively used for early diagnosis of systemic lupus erythematosus.