Pentraxins are a superfamily of conserved proteins characterized by the pentraxin domain. C-reactive protein (CRP) and serum amyloid protein (SAP) are recognized as classical short pentraxins, whereas pentraxin3 (PTX3) belongs to the long pentraxins. CRP and SAP are induced in the liver in response to IL-6. In contrast, PTX3 is produced by a variety of tissues and cells, such as vascular endothelial cells, macrophages, and neutrophils, predominantly in response to proinflammatory signals (bacterial products, IL-1, and TNF). PTX3 has also been observed in human atherosclerotic lesions of autopsy samples by immunohistochemistry, in association with macrophage and neutrophils infiltration. This localized expression pattern of PTX3 is believed to be indicative of primary inflammation stimuli, in contrast to CRP which is induced via secondary signals.