Turnover of autologous alpha 1-antitrypsin in a patient with congenital analbuminemia.

Despite very low amounts of albumin (1.7 mg/100 ml) the total plasma protein concentration of a patient with congenital analbuminemia was only slightly reduced to 6.3 g/100 ml. The lack of albumin is compensated by high concentrations of many other plasma proteins. Among the plasma proteins measured, alpha 1-antitrypsin showed a particularly high level. To investigate the underlying mechanism of this increase we purified plasma alpha 1-antitrypsin from the patient, labelled it with 125I, and studied its turnover in the analbuminemic patient and two normal volunteers. A half-life of 15 days in the patient compared with 7.5 and 8 days in the normal volunteers was found. The calculated synthesis rate of alpha 1-antitrypsin was about twice as high in the patient as in the controls. Therefore, both a longer half-life and an increased synthesis rate contribute to the high level of alpha 1-antitrypsin in the plasma of the analbuminemic patient.