PTX3 and graft versus host disease: Since PTX3, an acute-phase protein rapidly produced by vascular tissues as well as by cells of innate immunity in response to inflammation [14], is a rapid and reliable marker for primary local activation of innate immunity and inflammation in several autoimmune disorders [17, 19], we sought to determine whether PTX3 levels would change in the plasma of HSCT recipients and whether such changes could be used to predict GvHD severity and patient outcome as early as clinical manifestations appeared.