Angiotensin Converting Enzyme (ACE) Analysis

High in sarcoidosis, more often when the disease is active. Of value in assessing the response of sarcoidosis to corticosteroid therapy. Changes in serum ACE correlate with clinical status and results of gallium scans (which reflect presence and activity of inflammatory granulomatous lesions). Falling ACE level is a favorable prognostic sign. Rising levels may reflect activity uncontrolled by therapy.

Elevations have been reported in about 35% to 80% of cases of sarcoidosis. ACE levels are less likely to be increased with chronic sarcoidosis. Different admixtures of acute and chronic cases may explain some of the apparent variation in reported incidence of elevation in sarcoidosis. Elevations have been found in patients with diabetes mellitus, Gaucher disease, and leprosy. Twenty-five percent of 86 patients with acute histoplasmosis had elevated levels.³ Increased in some patients with primary biliary cirrhosis, amyloidosis, myeloma, some alpha₁-antitrypsin variants, Melkersson-Rosenthal syndrome, and hyperthyroidism. It has been found increased in some cases of hyperparathyroidism and in some instances of oncogenic hypercalcemia. Thus, it is not a specific marker for the diagnosis of sarcoidosis.⁴ Positives are also reported in patients with extrinsic allergic alveolitis, coccidioidomycosis, beryllium disease, asbestosis, silicosis, and alcoholic liver disease.⁵ ACE activity is decreased during starvation, independent of the level of thyroid activity (as monitored by T₃ levels).⁶

Kinetic