Objective: To redefine the utility of CSF-ACE as a selective indicator of probable CNS neurosarcoidosis.
Methods: The diagnosis of probable CNS neurosarcoidosis required: (a) biopsy evidence of systemic sarcoidosis, (b) cortical, brainstem, and/or spinal cord deficits, (c) enhancing lesions on brain and/or spinal cord MRI, and (d) exclusion of other etiologies which could account for the neurological deficits. Radioassay measurement of CSF-ACE activity was performed in 11 patients who met our criteria for probable CNS neurosarcoidosis and 207 control patients.
Results: The M +/- SD for CSF-ACE activity was significantly higher (p < 0.05) for the 11 probable CNS neurosarcoidosis patients (9.5 +/- 6.9 nmol/mL/min) than for the control patients (2.9 +/- 2.7 nmol/mL/min). The optimal CSF-ACE activity discriminator value was 8 nmol/mL/min. At this value, the sensitivity and specificity of CSF-ACE activity was 55% and 94%, respectively.
Conclusions: CSF-ACE activity is a useful biochemical marker of probable CNS neurosarcoidosis when brain and/or spinal cord MRI show diffuse enhancing lesions.