Plasma levels of endothelial‐derived haemostatic factors in autoimmune thrombocytopenia and haemolytic anaemia

The endothelial cell-synthesized haemostatic factors tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI) and von Willebrand factor (vWF) were assayed in a cross-sectional study of patients with immune thrombocytopenia (ITP) (n = 12) and autoimmune haemolytic anaemia (AIHA) (n = 3), and compared with a simultaneously selected contrast group of other hospitalized patients with obscure blood cytopenia at the time of sampling. All three factors were grossly elevated in both the study group and the contrast group. In the autoimmune patient group, the three haemostatic variables were significantly correlated with orosomucoid levels, demonstrating the acute-phase nature of the increased levels of vWF, tPA and PAI. These findings support the view that haemostatic factors of the vessel wall are implicated in the pathophysiology of a wide spectrum of diseases.