Toll-like receptors in rheumatic diseases: Are we paying a high price for our defense against bugs?

In the last decade Toll-like receptor (TLR) research has led to new insights in the pathogenesis of many rheumatic diseases. In autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis and systemic sclerosis TLR signaling is likely to be involved in tolerance breakthrough and chronic inflammation via combined Fc gamma receptors and TLR recognition of immune complexes. Furthermore, inflammatory diseases like psoriatic arthritis and gout also show more and more evidence for TLR involvement. In this review we will discuss the involvement of TLR signaling in several rheumatic diseases and stress their similarities and differences based on recent findings.