Nucleic acid recognizing Toll-like receptors and autoimmunity

The understanding of autoimmune diseases experienced an impressive boost since the Toll-like receptors (TLRs) have been identified as possible key players in autoimmune pathophysiology. Although these receptors recognize a variety of structures derived from viruses, bacteria, and fungi leading to subsequent initiation of the relevant immune responses, recent data support the idea that TLRs are crucial in the induction and perpetuation of certain autoimmune diseases, especially the systemic lupus erythematosus (SLE). In this review, we will summarize recent data on involvement of TLRs in the development of autoimmune diseases. We will focus on TLRs 7, 8, and 9 that were originally identified as receptors specific for bacterial and viral RNA/DNA, but more recent in vitro and in vivo studies have linked these receptors to the detection of host RNA, DNA, and RNA-associated or DNA-associated proteins in the context of autoimmunity.