[Functional activity of the alpha1-proteinase inhibitor in serum and bronchoalveolar lavage fluid in congenital lung emphysema]

Abstract

Pulmonary emphysema is thought to be due to an elastase-antielastase imbalance which leads to the destruction of alveolar walls. It is generally agreed that cigarette smoking is the major cause of acquired emphysema although many smokers fail to develop overt disease. Cigarette smoke inactivates alpha 1-proteinase inhibitor (alpha 1PI) which is believed to be the major antielastase in the lower respiratory tract. There is, however, controversy regarding the activity of alpha 1PI in smokers compared with nonsmokers. We, therefore, investigated the trypsin inhibitory capacity (TIC), the pancreatic elastase inhibitory capacity (PEIC), and the amount of immunoreactive alpha 1PI in serum and bronchoalveolar lavage fluid (BALF) of 24 individuals (15 smokers, 5 former smokers, 4 non-smokers) with clinical signs of emphysema and 32 persons (15 smokers, 6 former smokers, 11 non-smokers) without emphysema. Pancreatic elastase is known to be inhibited only by non-oxidised alpha 1PI whereas trypsin is inhibited by both native and oxidised alpha 1PI. Serum values of TIC/alpha 1PI and PEIC/alpha 1PI did not differ between the groups of subjects with emphysema (TIC/alpha 1PI: 0.71 +/- 0.12; PEIC/alpha 1PI: 0.44 +/- 0.06) and without emphysema (TIC/alpha 1PI: 0.68 +/- 0.13; PEIC/alpha 1PI: 0.41 +/- 0.07). Both serum-inhibitory capacities were found to be smaller than unit (= 1) indicating inactivation of alpha 1PI. BALF values of TIC/alpha 1PI showed a wide variation. TIC/alpha 1PI was greater than unity in 84% of subjects with emphysema (2.06 +/- 1.28) compared to 61% without emphysema (1.14 +/- 1.07) providing evidence for the presence of additional inhibitor(s) in those lavage fluids.(ABSTRACT TRUNCATED AT 250 WORDS)