A new player in hemolytic uremic syndrome: the plasma kallikrein-kinin system, a target of heme.

The study by Gerogianni et al. demonstrates activation by heme of coagulation factor XII and plasma prekallikrein in vitro, resulting in the release of the bioactive peptide kinins. It further shows that the plasma kallikrein-kinin system is activated in hemolytic uremic syndrome and suggests that heme is involved in this effect. The commentary examines the pathophysiological significance of these findings, discusses the translation of the biochemical findings to clinical situations, and considers the putative clinical consequences of plasma kallikrein-kinin system activation in hemolytic uremic syndrome.