Zur Transglutaminase-Aktivität der Untereinheit A des Faktor XIII in plättchenarmem und plättchenreichem Plasma sowie in Thrombozytenkonzentraten bei Patienten mit heterozygotem, doppelt heterozygotem und homozygotem Faktor XIII-Mangel

Table of Contents: From blood samples of four people with a normal factor XIII activity and four patients with a heterozygous F XIII deficiency, one double heterozygous and one homozygous patient, we have produced platelet poor plasma, platelet rich plasma and thrombocyte concentrates. With the modified version of Loewy’s simplified radiological incorporation method (by incorporation of C14 marked putrescine into casein) we measured the activity of F XIII in the fresh samples. After the destruction of the platelets by freezing and thawing the samples five times we measured the activity again. That way, we could show which components the total F XIII activity consists of. The plasmatic activity amounts 60%, the activity on the surface of the platelets amounts 35% and the activity on the inside of the platelets amounts 5%. In patients with complete congenital F XIII deficiency, platelets don’t either emit F XIII activity to the outside, nor do platelets take up F XIII in case of substitution of F XIII. Healthy persons have a higher F XIII activity (100% ± 30%) than heterozygous persons (50% ± 25%), whereas double heterozygous and homozygous patients don’t have any F XIII activity neither in platelets nor in their plasma. Different from double heterozygous and homozygous patients, heterozygous persons only sometimes have a bleeding tendency, which does not correlate with the actually measurable F XIII activity, but also depends on secondary risk factors. In the genesis of bleedings we differentiate between primary and secondary risk factors. The bleeding tendency is increased when - as a primary risk factor - there is a congenital genetic defect (disposition), whereas secondary, a