Angiotensin I converting enzyme in cerebrospinal fluid of patients with neurological diseases.

The angiotensin I converting enzyme activity (kininase II, EC 3.4.15.1) was measured fluorimetrically in cerebrospinal fluid (CACE) of 154 patients with neurological disorders and 27 controls. The concentrations of total protein, albumin, and immunoglobulins G and A were also determined. There was no correlation between CACE and sex or age, but a slight positive relation between CACE and total protein and an inverse correlation between CACE and albumin were observed. Compared to controls, significantly elevated CACE was found in acute untreated CNS sarcoidosis (P less than 0.0001), followed by viral encephalitis, CNS syphilis, Huntington's disease, and multiple sclerosis (P less than 0.001). In treated CNS sarcoidosis, only a minor increase of CACE was observed (P less than 0.05). The determination of CACE can be used for the diagnosis of neurological disorders.