Lupus anticoagulant and thrombosis: role of von Willebrand factor multimeric forms.
OBJECTIVE
Patients with lupus anticoagulant (LA) have an increased incidence of venous and arterial thrombosis whose pathogenesis is still unclear. High molecular weight von Willebrand Factor (vWF) multimers seem to play a causal role in shear stress-induced platelet aggregation and thrombus formation. We studied whether in patients with LA, alterations in the vWF multimers might coexist.


METHODS
The multimeric composition of plasma vWF was analysed by SDS-electrophoresis and immunoblotting in 43 subjects positive for LA. About 2/3 of the patients had had either ischemic stroke, recurrent abortions, deep vein thrombosis (DVT) or a combination of these; the remaining subjects had never had any thrombotic events.


RESULTS
An abnormal vWf multimeric pattern was found in 16 patients (37.2%); no correlation was found with the diagnosis, but the presence of abnormal vWF significantly correlated with the site of the thrombosis: indeed, it was never detected in subjects with DVT, but was found in 71.4% of patients with multiple abortions, in 50% of those with stroke and even in 25% of non-thrombotic patients.


CONCLUSIONS
The hypothesis is put forward that abnormal VWF may represent an additional risk factor to LA for arterial thrombosis.
Schinco
P
P
Department of Medicine and Experimental Oncology, University of Turin, Italy.
Borchiellini
A
A
Tamponi
G
G
Montaruli
B
B
Garis
G
G
Bazzan
M
M
Pannocchia
A
A
Modena
V
V
Pileri
A
A
D000026:Abortion, Habitual / Q000097:blood; D000293:Adolescent; D000328:Adult; D000368:Aged; D001158:Arteries; D002561:Cerebrovascular Disorders / Q000097:blood; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D015151:Immunoblotting; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D011247:Pregnancy; D013927:Thrombosis / Q000097:blood*; D014841:von Willebrand Factor / Q000032:analysis / Q000737:chemistry* / Q000502:physiology*
D016682:Lupus Coagulation Inhibitor; D014841:von Willebrand Factor