CRP and infection: Unlike CRP produced by the liver, Ptx3 is produced/secreted directly at the site of infection or inflammation by a range of cell types, including dendritic cells, macrophages, neutrophils, and endothelial cells, in response to inflammatory signals such as interleukin-1 and tumor necrosis factor.2 Ptx3 is a pattern-recognition molecule that senses and binds to pathogens, further enhancing their removal by complement-dependent immune mechanisms.3