The Role of Proteolytic Enzymes in the Treatment of Acute Hepatic Failure with Plasmapheresis

AbstractUsing phosphorylase kinase as a substrate during plasma exchange (PE), the proteoytic activity was demonstrated in the plasma of 2 patients with acute hepatic failure. The digestion pattern of phosphorylase kinase in the plasma filtrate was identical to that in the plasma, indicating a removal of proteases from the blood by this kind of treatment. Nevertheless, plasma proteolytic activity persisted in one patient until death in spite of 11 plasma exchanges, whereas in the other a normalization occurred after three plasma exchanges.Proteases in the plasma might be harmful to the patient, particularly if the concentration or function of the inhibitors alpha1-antitrypsin and alpha2-macroglobulin is reduced. Since these inhibitors are also removed during plasma exchange substitution should be performed with fresh frozen plasma to prevent a protease/antiprotease imbalance.