PARKINSONIAN SERUM CARRIES COMPLEMENT-DEPENDENT TOXICITY FOR RAT MESENCEPHALIC DOPAMINERGIC-NEURONS IN CULTURE

The presence of antibodies recognizing specific epitopes of dopaminerg ic neurons in serum of patients suffering of Parkinson's Disease (PD) as well as their capability to induce neuronal damage was investigated utilizing serum-free dissociated mesencephalic-striatal co-cultures. High affinity dopamine (DA) and GABA uptakes were assessed as specific , functional markers of dopaminergic and GABAergic cell viability, res pectively. Heat-inactivated serum samples from 18 and 13 patients suff ering from idiopathic and vascular parkinsonism, respectively and from 18 neurologic controls, were added to co-cultures on day 4 in vitro. Twenty four hours later, reconstituted rabbit complement was added for 60 min and uptake parameters as well as immunocytochemical staining f or tyroxyne hydroxylase (TH)-containing cells were subsequently assess ed. DA, but not GABA, uptake was significantly decreased only when com plement was added to cultures containing serum samples from 14 out of 18 patients with idiopathic parkinsonism and 3 out of 13 patients with vascular parkinsonism (Fisher test, P <0.01). Complement addition to cultures containing serum samples from seropositive parkinsonian patie nts significantly reduced immunocytochemical staining of TH-containing cells. Seropositive and seronegative patients did not differ in demog raphic and clinical features. These results suggest that a complement- dependent humoral immune response occurs mainly in idiopathic parkinso nian patients, but its clinical relevance remains to be established.