Many autoantibodies associated with nucleic acids are found in autoimmune diseases, and are important for analyzing pathophysiologic mechanisms. Toll-like receptors (TLRs) are receptor molecules for innate immunity and some of them recognize nucleic acids. Nucleic acids in autoantigens may stimulate TLR and activate antigen presenting cells as adjuvants. The Wa antigen was found as a transfer RNA (tRNA)-binding protein by RNA immunoprecipitation and identified as NEFA/Nucleobindin-2. Although the function of NEFA/Nucleobindin-2 is still not clear, it may be involved in secretion of proteins along with calcium metabolism and in protein translation by tRNA-binding ability.