Erythrocyte porphobilinogen deaminase activity in liver disease.

The activities of erythrocyte porphobilinogen deaminase were studied in patients with various liver diseases and in control groups. The lowest enzyme activities were found in patients with acute intermittent porphyria, and the highest ones in those with increased hemopoietic activity. Patients with liver cirrhosis or chronic active hepatitis had porphobilinogen deaminase activities that were significantly higher than in normal subjects and did not depend on disease activity. In patients with acute hepatitis, porphobilinogen deaminase activities varied depending on the phase of disease, being normal at onset and after 3-4 mo, and elevated to the values observed in chronic liver disease between 2 and 4 wk of hospitalization. The differences in porphobilinogen deaminase activities between patients with liver disease and controls did not relate to red cell age as determined by density gradient centrifugation. Therefore, although the mechanism responsible for the increase in porphobilinogen deaminase activities in liver disease is not clear, the results of this study suggest that it is independent of the presence of immature red cells in the circulation.