[Serum adenosine deaminase and its isozyme activities in patients with Parkinson's disease].

Adenosine deaminase (ADA) is a deaminating enzyme consisting of isozymes ADA 1 and ADA 2. We measured the activities of total ADA, ADA 1 and ADA 2 in serum obtained from 42 patients with Parkinson's disease (PD). Patients were divided into 10 cases of stage I, 20 of II, 11 of III and 1 of IV according to the clinical stages described by Hoehn and Yahr. The total and ADA 2 activities were significantly higher in patients as compared with normal controls (p < 0.01, respectively). However, this study did not detect any tendency for elevated total ADA or its isozyme activities with advance in clinical stages described by Hoehn and Yahr. ADA and ADA 2 are thought to have important roles in the regulation of the immune function. On the other hand, recent reports have suggested that immunological abnormality may be responsible for the developing of PD. Our results also suggest that high serum ADA activity may be involved in the pathogenesis of PD through the alteration of the immune function.