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[Clotting factor VIII in Sneddon syndrome].

[sneddon syndrome]

Hyperactivity of coagulation factor VIII (fVIII) marks hypercoagulation. FVIII enhances activity of factor IX and their combination activates factor X, which is of primary importance in prothrombin transformation into thrombin, on the phospholipid membrane. The activity of fVIII was studied in 28 patients (26 women, 2 men, mean age 49.6 +/- 7.8 years) with Sneddon's syndrome (SS). SS manifests clinically similarly to primary antiphospholipid syndrome (PAS). The leading of them are ischemic disorders of cerebral circulation (IDCC) and advanced livedo present in all the examinees. Hyperactivity of fVIII was registered in 21 (75%) of 28 patients. Most of thrombosis-related symptoms occurred more frequently in patients with high than normal activity of fVIII: ischemic strokes (91% vs 57%, p > 0.05), repeated strokes (71% vs 0%, p = 0.0014), transient IDCC (76% vs 57%, p > 0.05), vascular dementia (43% vs 0%, p > 0.05), ischemic heart disease (43% vs 0%, p > 0.05), thickening of heart valves according to echocardiography (91% vs 57%, p > 0.05), peripheral venous thromboses (24% vs 0%, p > 0.05). In high fVIII activity cardiolipin antibodies occurred more rarely (24% vs 43%, p > 0.05) but lupus anticoagulant was seen more often (47% vs 14%, p > 0.05). High fVIII activity was in 8 of 12 aPL-negative patients. It is demonstrated that elevated fVIII activity is an essential mechanism of thrombosis development in SS. The cause of this enhanced activity is suggested to be special aPL in interaction with which fVIII becomes insensitive to inactivation with protein C. The activity of protein C was normal in all the cases.