Coagulation factor VIII

Factor VIII, or antihaemophilic factor (A), is plasma glycoprotein that circulates in a complex with von Willebrand factor. It is about 330kDa.

Its primary site of production is not clear; it is synthesised by endothelial cells of the liver and other organs. Congenital (or acquired) deficiency of FVIII is the cause of haemophilia A.

In liver disease, FVIII level are often paradoxically elevated, which can produce a normal aPTT. Severe hepatosis may increase the aPTT as the liver sinusoidal endothelial cells become involved.

The normal FVIII concentration is said to be around 0.1-0.2μg/mL¹; the 100% used as normal concentration must be somewhere around this value.

Liver transplantation has been noted to ‘cure’ haemophilia by restoring production of FVIII².

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Footnotes

1. Green D. Chapter 3 - FVIII anatomy and physiology. In: Green D, editor. Hemophilia and von willebrand disease [Internet]. Academic Press; 2018. p. 33–47. Available from: https://www.sciencedirect.com/science/article/pii/B9780128129548000035 ↩

2. Bontempo FA, Lewis JH, Gorenc TJ, Spero JA, Ragni MV, Scott JP, et al. Liver Transplantation in Hemophilia A. Blood. 1987 Jun 1;69(6):1721–4. ↩