Alterations of primary haemostasis in mixed connective tissue disease (MCTD).

Willebrand-factor antigen level and structure analysis, ristomycin-cofactor assay, beta-thromboglobulin and thromboxane metabolite estimations were performed in 22 patients with mixed connective tissue disease to evaluate the incidence and the possible role of haemostatic alterations in the complications occurring during the course of the disease. High levels of Willebrand-factor antigen and ristomycin-cofactor activity were detected in patients with thrombocytopenia, previous thrombotic event, pulmonary vascular lesions and usually in the presence of circulating anti-endothelial antibodies. Increased platelet activation could have been found in antibody positive cases and in patients with thrombocytopenia as well. The documented alterations of endothelial and platelet functions may play important role in the vascular complications of mixed connective tissue disease.