thromboplastin and Skin-Diseases--Vascular

Livedo reticularis is associated with collagen vascular diseases and other vaso-occlusive disorders in a substantial number of cases. In the remaining cases the cause of livedo reticularis is still unknown. (i.e., idiopathic). We sought to determine a possible causal relationship between idiopathic livedo reticularis and autoimmune factors associated with the coagulation system, including antiendothelial cell antibodies. Nine patients with idiopathic livedo reticularis were studied. All patients were found to have normal platelet count, fibrinogen levels, and prothrombin and activated partial thromboplastin times, as well as negative results for Venereal Disease Research Laboratory and D-timer tests. Anticoagulant activity was detected in 2 patients: one had positive results of thromboplastin titration index and Russell's viper venom test, as well as increased levels of anticardiolipin antibodies and anti-endothelial cell antibodies; the other has positive thromboplastin titration index, mildly increased levels of anti-endothelial cell antibodies, and markedly increased levels of antinuclear antibodies. A third patient had mildly increased levels of anti-endothelial cell antibodies alone, and a fourth patient had mildly increased levels of antinuclear antibodies only. The clinical outcome was uneventful in all of the patients during an 18-month follow-up period. These findings suggest involvement of autoimmune factors associated with the coagulation system in some patients with idiopathic livedo reticularis, whose clinical significance remains to be determined.

Topics: Adolescent; Adult; Antibodies, Anticardiolipin; Antibodies, Antinuclear; Blood Coagulation; Child; Endothelium; Female; Humans; Male; Middle Aged; Skin Diseases, Vascular; Thromboplastin

Markers of endothelial cell activation were measured in 28 patients presenting with various forms of limited or focal type cutaneous vasculitis. Plasma levels of tissue plasminogen activator antigen (t-PA:Ag), plasminogen activator inhibitor type 1 antigen (PAI-1:Ag) and PAI-1 activity, fibrin plate, von Willebrand factor antigen (vWF:Ag), tissue factor (TF) and soluble thrombomodulin (sTM) were measured. In comparison with the control group (n = 20) there was a significant increase in t-PA:Ag, vWF:Ag and TF (P < 0.05, Mann-Whitney U-test) in the cutaneous vasculitis group. This study confirms that measurable degrees of endothelial activation occur in cutaneous vasculitis. Cutaneous vasculitis includes a diverse group of clinical conditions, which are associated with inflammatory changes in cutaneous blood vessels with local fibrin deposition. The aetiology and pathogenesis of the majority of these entities remain unknown. Causative mediators are thought to include immune complexes, anti-endothelial cell antibodies, cytotoxic lymphocytes and viruses. Histologically, immune complexes and complement are frequently detected on the vessel wall, and serologically anti-endothelial antibodies are often detected in patients with vasculitis and in systemic lupus erythematosus (SLE) which correlate with the severity of cutaneous vasculitis, arthritis and nephritis. Lymphocyte-mediated toxicity to endothelial cells has been reported in a small number of patients with giant cell arteritis and Takayasu's arteritis. The vascular endothelium plays a central part in the control of haemostasis. Under physiological conditions endothelial cells present an anticoagulant surface to blood constituents, partially due to surface expression of heparan sulphate and thrombomodulin (TM). Heparan sulphate binds antithrombin III (ATIII), thereby accelerating inactivation of intrinsic coagulation enzymes. Thrombomodulin is an endothelial cell surface glycoprotein which promotes anticoagulation by forming a complex with thrombin which then activates protein C. Activated protein C together with a cofactor, protein S, inactivates FVa and FVIIIa. von Willebrand factor (vWF) is synthesized by endothelial cells, stored in Weibel-Palade bodies and released into the circulation upon endothelial stimulation. vWF mediates the binding of platelets to the subendothelium and is the carrier molecule for FVIIIC. The endothelium controls fibrinolysis by producing t-PA and its inhibitor PAI-1. Inflamma

Topics: Adult; Aged; Endothelium, Vascular; Female; Fibrinolysis; Humans; Male; Middle Aged; Pilot Projects; Plasminogen Activator Inhibitor 1; Plasminogen Activators; Skin Diseases, Vascular; Thrombomodulin; Thromboplastin; Vasculitis; von Willebrand Factor