Division d'angiologie et d'hémostase, Hôpital cantonal universitaire, CH-1211 Genève, Suisse.
Plasminogen activator inhibitor type 2 (PAI-2) is one of the principal inhibitors of the plasminogen activator system. It is a member of the serpin (serine protease inhibitor) family of proteins and inhibits efficiently urokinase (u-PA) and two chain tissue-type plasminogen (t-PA), but only weakly single chain t-PA. There are two forms of PAI-2 : a 47 kDa, non-glycosylated, intracellular form and a 60 kDa, glycosylated, secreted form. PAI-2 is present in the plasma of pregnant women, in gingival fluid, in monocytes/macrophages and in keratinocytes. PAI-2 biosynthesis is increased by tumor necrosis factor, interleukin-1 and endotoxin and diminished by glucocorticoids. The information available on PAI-2 suggests that it plays a role in inflammatory processes, in tumor invasion and metastasis, in placental function and fetal growth, in the differentiation of keratinocytes and in skin formation. It may also play a protective role in apoptosis.