Immune regulatory cells: circulating biomarker factories in cardiovascular disease.

TLRs (Toll-like receptors) are the first line of defence of the innate immune system. These receptors recognize not only exogenous but also endogenous ligands that are expressed following arterial injury and atherosclerotic disease. Expression of TLR2 and TLR4 is observed in macrophages and different vascular cells and is increased in atherosclerotic disease. It is suggested that TLR expression and functional responsiveness following ligation could serve as biomarkers for atherosclerotic disease progression. Recently published research papers support the concept that the TLRs are fast responders upon arterial injury. In the present issue of Clinical Science, Ishikawa and co-workers provide new evidence emerges that points to the potential prognostic properties of the TLRs.