Serum from Sydenham's chorea patients modifies intracellular calcium levels in PC12 cells by a complement-independent mechanism.
ABSTRACT The proposed pathogenesis of Sydenham's chorea (SC) is an autoantibody-mediated basal ganglia dysfunction. Our study has shown that incubation of PC12 cells with complement-inactivated serum from SC patients was associated with a significant increase in Ca2+ levels evoked by KCl stimulus (mean +/- SEM, 341.0 +/- 8.7% of fluorescence intensity, arbitrary units) when compared with incubation with control serum (313.8 +/- 8.7% of fluorescence intensity, arbitrary units; P = 0.01). The increase in Ca2+ levels determined by SC patients sera correlated directly with the enzyme-linked immunosorbent assay optical density values for anti-basal ganglia antibodies. Our study supports the hypothesis that antibodies against basal ganglia in SC may cause their dysfunction.