Plasma von Willebrand Factor in Patients with Megaloblastic Anemia

Abstract

Plasma from five patients with megaloblastic anemia (including three patients with Hashimoto thyroiditis as an additional complication) were examined for the presense of an abnormality in von Willebrand factor (vWF) using a 0.1% sodium dodecyl sulfate (SDS) -1.5% agarose gel electrophoresis. Also, the plasma samples were evaluated for FVIII/vWF activities. A mild decrease of FVIII/vWF activities and a low ability of ristocetin-induced platelet aggregation and/or adhesiveness to glass beads were found in two patients with Hashimoto thyroiditis (out of three patients). The loss of the larger multimers of plasma vWF was demonstrated in these two patients. But, after supplemental therapy (both levothyroxine sodium and hydroxocobalamin in one case, and hydroxocobalamin only in another case), their multimeric compositions were found to be normal. Otherwise, there was no abnormality in the plasma vWF of two patients with megaloblastic anemia who did not have Hashimoto thyroiditis as a compliation. These findings suggest that the mechanism with which the autoimmune antibodies and/or vitamin B12 deficiency may be associated might have a relationship with the pathophysiology in development of a kind of acquired von Willebrand syndrome.