Objective: To determine the extent and significance of serum angiotensin-converting enzyme (ACE) elevation in multiple sclerosis (MS) and the correlation between serum ACE activity and clinical and magnetic resonance imaging (MRI) indicators of disease activity.
Design: A retrospective cross-sectional study of 45 consecutive patients with clinically definite MS and a longitudinal study of 30 additional patients with clinically definite MS involved in a long-term study of neurologic function and MRI in MS.
Setting: Comprehensive MS center of a tertiary care university hospital.
Subjects: A total of 75 patients with clinically definite MS and 31 healthy controls.
Methods: Serum ACE activity was measured using a spectrophotometric assay and correlated with clinical indicators of disease activity and with total cerebral MS lesion volume measured by MRI.
Results: An elevated ACE activity was found in 17 (23%) of 75 patients with MS as compared with 2 (6%) of 31 healthy controls. Changes in serum ACE activity correlated with changes in total plaque volume on MRI.
Conclusions: Serum ACE activity may be an indicator of disease activity in longitudinal analysis. Also, elevated ACE activity in a patient with otherwise typical MS need not raise suspicions of alternative diagnoses.