[Antitrypsin activity of the urine and alpha 1 protease inhibitor].

The urinary trypsin inhibitory capacity (TIC) is mainly due to the excretion of an inhibitor which is immunologically related to inter-alpha:trypsin inhibitor (ITI). However, alpha 1 protease inhibitor (alpha 1 PI) can be found in urine of patients with proteinuria. When this one is greater than 1 g/l, the measured TIC is more or less markedly related to the amount of alpha 1 PI present in the analyzed sample. The antitryptic activity of alpha 1 PI can be ruled out by incubating urine with specific anti-alpha 1 PI immunoglobulins. An identical result is obtained by acidification of the sample prior to TIC determination. Moreover, after freezing of urine, only the antitryptic activity of alpha 1 PI is strikingly decreased. Thus, in the presence of a significant proteinuria (greater than 1 g/l), a preliminary acidification of urine allows a suitable and specific measurement of TIC due to the inhibitor immunologically related to ITI. Thus, this one is a sensitive, useful and easy test for detecting and monitoring infections.