Angiotensin-Converting Enzyme in Neurosarcoidosis

To the Editor.  —We read with great interest the article by Sethi et al in the June 1986 issue of the Archives.¹ We wish to point out another important aspect of neurosarcoidosis that was not discussed by the authors, namely, determination of angiotensin I—converting enzyme (ACE) levels in the cerebrospinal fluid (CSF) of patients with suspected neurosarcoidosis.^2-5High levels of CSF ACE may support the diagnosis of neurosarcoidosis even though the serum ACE levels are within the normal range.^2,3 Furthermore, monitoring the CSF ACE levels may aid in patient management and follow-up, since CSF ACE levels decrease when the disease is clinically remitted due to corticosteroid therapy.^3,5 There is no correlation between the serum and CSF ACE levels in patients with neurosarcoidosis, nor is there any correlation between CSF ACE and CSF total protein or albumin levels in such cases.³ The CSF ACE is most