[Behavior of blood ACE (angiotensin-converting enzyme) in pulmonary silicosis]

Determination of angiotensin enzyme (A.C.E.) in serum has recently been indicated as an undoubtedly useful parameter for the differential diagnosis of pulmonary sarcoidosis, considering the specific increase in this disease compared to other pulmonary granulomatoses (tuberculosis, mycosis, etc.). The aim of this study was to ascertain whether a change in this enzymatic activity occurs in silicosis of the type with small and large opacities. The results show how in silicosis, too, the serum A.C.E. values are significantly higher compared with healthy controls, but the levels are so moderate that they do not justify the use of A.C.E. determination for diagnosis of pulmonary sarcoidosis. A possible explanation for this is that both these granulomatous diseases, in which activation of the lung macrophages and epithelioid cells takes place, there is an increased production of A.C.E.; while in sarcoidosis, however, these cells tend towards a secreting type of activity, in silicosis a phagic type activity is still predominant due to the toxicity of silica for the macrophages.