Serum Angiotensin-Converting Enzyme in Coal Worker's Pneumoconiosis

Abstract

We have read with great interest the article from Nordman et al1Nordman H Hoskinen H Froseth B Increased activity of serum angiotensin-converting enzyme in progressive silicosis.Chest. 1984; 86: 203-206Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar reporting the relation between high serum angiotensin-converting enzyme (SAGE) activity in silicosis and the progression and severity of fibrosis. We have measured SAGE activity in 141 pneumoconiotic coal miners, 40 healthy coal miners and 30 controls, according to the method of Lieberman. Our results2Wallaert B Deflandre J Ramon P Alluin-Aigouy F Ramon Ph Voisin C L'enzyme de conversion de l'angiotensine I chez le mineur de charbon.Rev Fr Mal Respir. 1983; 11: 506-507Google Scholar demonstrate a high proportion (45 percent) of elevated SAGE level in coal worker's pneumoconiosis (CWP). Results are shown on Table 1 according to the ILO 1980 classification of roentgenograms of pneumoconiosis. The mean SACE activities were significantly higher in CWP than in controls and non pneumoconiotic coal miners (p<0.05). Patients showing small rounded opacities (types p, q, r) had higher values than those with large opacities (types A, B, C) (p<0.05). SACE levels did not vary according to the roentgenographic profusion categories (1, 2 or 3). Serial measurements of SACE in 50 CWP patients did not demonstrate significant variations at six month intervals. No statistically significant correlation was found between SACE levels and serum immunologic abnormalities, ie, presence of rheumatoid factor, antinuclear antibodies and circulating immune complexes. Cellular study of bronchoalveolar lavage (BAL) in 30 patients showed an increased number of recovered cells, comprised of alveolar macrophages without any difference in total or differential BAL cell count whatever SACE level.3Voisin C Gosselin B Ramon Ph Wallaert B Aerts C Lenoir L Le lavage broncho-alvéolaire dans la pneumoconiose des mineurs de charbon. Aspects cytologiques.Rev Fr Mal Respir. 1983; 11: 455-466PubMed Google Scholar Evolutivity of CWP was evaluated in 100 patients using a retrospective study of chest x-ray films. The progression of both profusion and type of lung opacities was assessed since the beginning of occupational risk by double-blind examination of annual roentgenogram. There was no significant correlation between the progression of the disease and SACE activity. Conversely, we recently observed three cases of rapidly progressive pneumoconiosis (CWP, 1 case; silicosis, 2 cases) characterized by very high SACE activity (>mean +4 units of standard deviation), associated with an increased alveolar lymphocytosis.Table 1Results of Serum Angiotensin-converting Enzyme (SACE) in 30 Healthy Controls, 40 Nonpneumoconiotic Coal Miners and 141 Patients with Coal Worker's Pneumoconiosis According to ILO ClassificationPatientsSACE*Results expressed as the mean ± standard deviation (X¯ ± SD)Sace >X+2 SD†Percentage of patients showing SACE level>mean + 2 SD (% patients)Healthy controls n = 3025.2 ± 4.7–Non pneumoconiotic coal miners n = 4029.5 ± 9.525Coal worker's pneumoconiosis All patients (n = 141)33.8 ± 13.045Small rounded opacities n = 6338.4 ± 13.356Type p (n = 12)43.6 ± 16.170q (n = 35)37.4 ± 12.648r (n = 16)38.3 ± 14.152Large opacities (n = 78)32.4 ± 12.542Type A (n = 26)32.8 ± 11.546B (n = 22)34.4 ± 12.334C (n = 30)30.8 ± 13.430* Results expressed as the mean ± standard deviation (X¯ ± SD)† Percentage of patients showing SACE level>mean + 2 SD Open table in a new tab Evidence of elevated SACE levels in non pneumoconiotic coal miners lead us to suggest that interaction between mineral particles and alveolar macrophages may be in part responsible for the increased SACE production in CWP. However, little information is available concerning the relationship between type of mineral particles and secretories activities of alveolar macrophages. In our study, SACE activity is not related to progression of fibrosis in CWP but acute forms of CWP and silicosis are associated with high SACE activity.