Haematologia 19. (1986)
1986 / 1. szám - Soulier, J. P. - Gozin, D. - Lefrére, J. J.: Assay of des-gamma-carboxyprothrombin using staphylocoagulase. Application to the diagnosis of cellular hepatocarcinoma
Haematohgia 19 (l),pp. 3—12 (1986) Assay of Des-Gamma-Carboxyprothrombin Using Staphylocoagulase. Application to the Diagnosis of Cellular Hepatocarcinoma J. P. Soulier, D. Gozin, J. J. Lefrère Centre National de Transfusion Sanguine, 6 rue Alexandre-Cabanel, 75739 Paris, Cedex 15, France (Received 18 March 1985; accepted 16 May 1985) A new clotting method is described to assay des-gamma-carboxyprothrombin (DCP), using staphylocoagulase and adsorbed undiluted citrated plasma. The thrombincoagulase formed was tested with a chromogenic substrate. The results were expressed in milliunits (m.u.). All 96 normal plasmas had less than 15 m.u. (mean 3.58 m.u.). Out of 56 non-hepatectomized cellular hepatocarcinomas, 40 had DCP levels between 20 and 420 m.u. (average between 40 and 60 m.u.); 71.4 % of cellular hepatocarcinoma had an increased DCP and 90% were positive either in alpha-foetoprotein or in DCP. Ten cases of non-cellular hepatocarcinomas had normal DCP levels. We found no cases of cirrhosis or chronic hepatitis, whether active or persistent, with abnormal level of DCP. Out of 127 patients tested, no case was found with a high DCP and a low level of “total factor II”, which could be interpreted as a vitamin K deficiency. Only one case of hepatocarcinoma had 25 m.u. of DCP and a low total factor II (20%) and 2 had less than 10% total factor II with no detectable DCP. Keywords: des-gamma-carboxyprothrombin (DCP), hepatocarcinoma Introduction Liebmanetal.have recently reported [3] that des-gamma-carboxyprothrombin (DCP) was increased in 67% of the cases of cellular hepatocarcinoma. Plasma prothrombin is synthetized in the hepatocyte, where it is modified in the presence of vitamin K by a post-translational gamma-carboxylation of 10 glutamic acid residues near its end-terminal part, this allows the molecule to become functional, i.e. to react with calcium and with phospho-lipids. The vitamin K related carboxylation also permits the adsorption of factor II (as well as of factors VII, IX and X) on different adsorbents, like barium sulphate or aluminium hydroxide [4, 6]. The American authors used a radio-immunological method to assay DCP, which needed, on the one hand, the preparation of a specific antibody reacting against “normal” prothrombin, and, on the other hand, the use of another antibody active against DCP. Such reagents are difficult to prepare in a reproducible way. If the RIA has the advantage of allowing DCP assay on serum, it has the disadvantage of being a long and complex technique, difficult to apply in many clinical laboratories. VNU Science Press, Utrecht Akadémiai Kiadó, Budapest