[Phenotype Pi and alpha 1 antitrypsin deficiency in types A and B chronic obstructive bronchopneumopathies]

Abstract

The authors studied 79 patients with chronic obstructive lung disease. (COLD) (FEV1/VC less than 70%). Patients with chronic asthma were excluded from the series. These patients with COLD were divided up into 2 groups, depending on radiological and clinical criteria: (1) Type A, primary emphysema, 24 patients; (2) Type B, chronic bronchitis, 49 patients. 6 patients of type X (intermediate type) were excluded. Their respiratory function tests were studied together with clinical and radiological findings and blood gases. Furthermore, were studied in each patient, the antitrypsic activity and the serum concentrations of alpha-1-antitrypsin and phenotype Pi. Group A were, on average, more obstructive than group B. The ratio FEV1/VC was 31% +/- 7% in group A, against 46% +/- 13% in group B. The serum antitrypsin activity and the serum concentration in alpha-1-AT were on average close to normal in both groups. However, group A was divided up into two populations: a small population with a low concentration of alpha-1-AT, and a large population with normal alpha-1-AT. A study of the incidence of various phenotypes in groups A and B showed a significantly higher frequency of phenotype ZZ in group A (12.5%) than in group B (10%). All ZZ subjects were of clinical type A. There was no significant difference in the incidence of other phenotypes encountered. Serum alpha-1-antitrypsin concentration was very low in 3 ZZ patients. One case with phenotype SZ and one MM showed intermediate levels. The authors emphasize the low percentage of cases of pulmonary emphysema which may be explained by an alpha-1-antitrypsin deficiency. Nevertheless, this preliminary report should be completed by a study of a larger sample of patients with COLD with control of the phenotype.