Abstract
A 69-year-old man with hemorrhagic tendency caused by a specific inhibitor against factor V was described.
He was admitted because of severe hematuria. Coagulation studies showed a factor V level of 1% and cross correcting experiments showed a presence of factor V inhibitor in his plasma. The inhibitor was suggested to belong to IgG fraction, because it was found on the second peak of the Sephadex-G 200 gel filtration of the plasma and precipitated by 33% saturation with ammonium sulfate. On admission, antinuclear antibody and rheumatoid factor were present, but LE cells were absent. A high level of FDP was also present, but no orther signs of DIC were present. He was treated with fresh frozen plasma for one week, but no improvements were observed in coagulation studies. Then he was treated with predonisolone, which resulted in a disappearence of the inhibitor. At the same time, antinuclear antibody, rheumatoid factor and FDP also disappeared. Although the occurrence of the inhibitor in this case was assumed to be associated with some “autoimmune” mechanisms, few evidences were found to show the presence of the underlying disorder.
