In order to know the pathological significance of elastase (ELP) released from leukocytes in blood circulation, the laboratory findings which may have connection with high ELP level in sera were searched. ELP value was examined using frozen sera obtained from two laboratories (164 and 125 cases). The value determined using Suc-Ala-Tyr-Leu-Val-pNA remained unchanged by repeated freezing and thawing. The results obtained were as follows.
1) ELP level obtained in sera from healthy human blood (control) was 315±165ng/ml.
2) The value increased significantly in the patients sera which showed high value of leucine aminopeptidase (LAP), γ-GTP, GOT, GPT and ALP. ELP level in sera which LAP, γ-GTP, GOT, GPT and ALP showed high level was 1, 370±825ng/ml (n=18), and it was 690±370ng/ml (n=15) in sera showing high level of only LAP and γ-GTP.
3) A correlation coefficient between ELP and LAP was 0.78, and regression line was y=526x+130 (x=ELP, μg/ml). The coefficient between ELP and γ-GTP was also 0.78, but that between ELP and GOT (or GPT) was low (r=0.29, 0.38).
4) ELP level in sera of patients with renal failure (n=30) was 245±70ng/ml, and it was lower than that in control sera.