Plasma levels of pentraxin-3, an acute phase protein, are increased during sickle cell painful crisis

The painful crisis accounts for the majority of sickle cell disease (SCD) related hospital admissions. The prototypic long pentraxin 3 (PTX3), an acute phase protein, is elevated in patients with inflammatory and ischemic states. As the sickle cell painful crisis is associated with both inflammation and tissue ischemia, we questioned whether plasma PTX3 levels are increased during and associated with painful crisis severity. Furthermore, since PTX3 up-regulates endothelial expression of tissue factor we studied PTX levels in relation to markers of endothelial and coagulation activation. Plasma levels of PTX3, ultra-sensitive C-reactive protein (US-CRP), prothrombin fragment 1+2, thrombin-antithrombin (TAT) complexes, von Willebrand Factor antigen and soluble vascular adhesion molecule-1 were determined in 105 asymptomatic sickle cell patients, 33 patients during painful crisis and 30 race matched healthy controls. Plasma PTX3 levels were comparable between patients in asymptomatic state and healthy controls, but significantly higher during painful crisis (P<0.01). US-CRP levels were higher in asymptomatic patients compared to controls (P<0.0001) and increased further during painful crisis (P<0.0001). PTX3 levels at presentation with painful crisis correlated significantly with the duration of subsequent hospital admission (r s=0.43; P=0.013), whereas US-CRP levels did not. PTX3 levels did not correlate with markers of hypercoagulability. The increase of PTX3 levels during painful crisis and their relation to the duration of subsequent hospital stay suggest that PTX3 might serve both as a diagnostic and severity marker of the painful sickle cell crisis.