Search

The clinical course and pulmonary function tests of individuals with severe Alpha-1-Antitrypsin (Alpha-1-AT) deficiency reveal a marked interindividual variability. 4 patients with PI type ZZ and 2 patients with PI type SZ had been identified by neonatal cholestasis. None had pulmonary symptoms at a mean age of 13 (range 9-16) years. Lung function tests disclosed signs of incipient pulmonary emphysema in one girl. Bronchial hyperreactivity had led to the diagnosis of Alpha-1 AT-deficiency (PI type ZZ) in another girl at the age of 7 years. The biochemical analysis of the serum of three children (two PI ZZ and one PI SZ) revealed additional protease inhibitors that may be effective as compensatory mechanisms. The lack of those protective factors as well as the presence of environmental hazards may contribute to the increased risk of emphysema in individual patients.

Both the clinical course of the homozygous alpha 1-PI deficiency and also the pulmonary function and measured clinical parameters in these children revealed very marked inter-individual fluctuations. In one child, the lung function revealed certain signs of incipient pulmonary emphysema. The biochemical parameters of two children revealed TIC/alpha 1-PI- and PEIC/alpha 1-PI ratios greater than 1. This indicates that, in addition to alpha 1-PI, further inhibitors may develop a compensatory effect.

Smoking habits have no differentiating effect on the functional activity of protease inhibitor (alpha 1PI) in the serum and bronchoalveolar lavage fluid (BALF). In the BALF, the trypsin-inhibitory capacity TIC/alpha 1PI ratio is significantly greater in patients with emphysema than in non-emphysematous subjects. PIC/alpha 1PI ratios that are greater than 1 demonstrate the existence of additional antiproteases in the lower respiratory tract.

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)