A specific, fluorescent activity staining procedure applied to plasma and red blood cells in congenital factor XIII deficiency.

The activity staining procedure introduced by Stenberg & Stenflo (1979) has been applied to studies on human blood transamidases (transglutaminases; endo-gamma-glutamine:epsilon-lysine transferases; e.g. factor XIII). The technique combines agarose gel electrophoresis with activity staining based on the transamidase catalysed incorporation of monodansylthiacadaverine (N-(5-amino-3-thiapentyl)-5-dimethylamino-1-naphtalenesulfonamide) into casein. The method permits detection of plasma factor XIII activity down to 1% of the normal adult standard. The technique was used on plasma from two patients with tentative congenital plasma factor XIII deficiency (based on clot solubility). No activity was found in platelet poor as well as in platelet rich plasma which confirmed the diagnosis. In the erythrocytes studied in genetic determinations of the plasma and red blood cell transamidases. Using immunoelectrophoresis, the plasma factor XIII b subunit was found to be 43% and 44% of the concentration in normal standard plasma.