Brain protein kinase in synaptic vesicles is inhibited by a factor in sera from systemic lupus erythematosus patients with central nervous system manifestations.

Sera from systemic lupus erythematosus patients with clinical central nervous system manifestations had a high mean percent of brain synaptic vesicle protein kinase inhibition (62 +/- 9.3, P less than 0.001). This conclusion was derived from screening sera of a total of 287 patients with heterogeneous diseases and from 12 healthy controls. Low levels of synaptic vesicle protein kinase inhibition also were detected in the sera of patients with certain autoimmune, inflammatory, neurological and/or psychiatric symptoms. Because 87.5% of the patients whose sera showed strong synaptic vesicle protein kinase inhibition (over 50%) had neuropsychiatric manifestations, we postulate this relationship may be due to the presence of an inhibitor factor, of which the etiology and molecular characteristics were investigated.