[The evaluation of serum angiotensin-converting enzyme in silicosis and silicotuberculosis]

In order to verify the value of the determination of serum angiotensin converting enzyme (ACEs) in the assessment of silicosis and silicotuberculosis, we studied 105 subjects: 61 suffering from silicosis, 12 from silicotuberculosis, 19 from tuberculosis and 13 from chronic obstructive pulmonary disease (COPD). The patients with silicosis and silicotuberculosis were classified into two categories on the basis of the radiological pattern of pneumoconiosis according to the ILO 1980 CLASSIFICATION: mild silicosis (from 1/1 to 2/1) and severe silicosis (from 2/2 to 3+ and/or conglomerate masses). ACEs values were higher in the subjects suffering from silicotuberculosis and silicosis; in the latter, however, we did not find any significant relation between ACEs values and the radiological pattern. The lowest values of ACEs were found in the COPD group. Our data showed a statistically significant difference between silicotic or silicotuberculotic patients and the COPD group (p less than 0.05). It can be supposed that COPD, which was also found in all subjects suffering from silicosis or silicotuberculosis, might have caused an underestimation of the observed ACEs values which, however, were higher than normal. This increase might have been caused by a numerical or functional enhancement of the macrophages, which produce ACE and play an important role in the pathogenesis of such diseases.