Human Factor VIII: Morphometric Analysis of Purified Material in Solution

Abstract

Study of purified human factor VIII in buffer by freeze-etch electron microscopy reveals rounded, rod-shaped particles measuring 22 by 42 nanometers. When thrombin was added to purified normal factor VIII, there was a rapid loss of rod-shaped particles during the first 15 minutes of incubation at 37 degrees C. Purified plasma from two patients with severe hemophilia contained spherical particles measuring 10 to 50 nanometers in diameter, with no evidence of significant numbers of rod-shaped forms. Negatively stained and unstained air-dried samples of factor VIII corroborate the relative shape and size differences between normal and hemophiliac material.