Histiocytosis X. VI. Angiotensin-converting enzyme activity

The activity of the endothelial and macrophage derived angiotensin-converting enzyme in blood was within normal range in 12 patients with histiocytosis X, independent of extent and activity of the disease. In contrast to sarcoidosis and Gaucher's disease, histiocytosis X is not associated with elevated levels of angiotensin-converting enzyme.