Platelet autoantibodies in dementia and schizophrenia. Possible implication for mental disorders

Platelets isolated from blood of demented and schizophrenic patients were found to bear surface antibodies at a considerably higher titer than those found on platelets from normal age-matched groups or patients with affective disorders. The platelet count in demented and schizophrenic patients correlated inversely with the level of the platelet associated antibodies (PAA) which suggested an autoimmune route of opsonization. In most individual cases of dementia or schizophrenia PAA and platelet count were found to oscillate with time between high PAA-low platelet number and low PAA-high platelet number in approximately inverse correlation. PAA isolated from demented patients were found to cross-react with platelets from normals and with brain tissue from rats. Furthermore, molecular weights of specific brain antigens were identified by binding to PAA. These observations support the possibility that PAA might be implicated in the etiology of some mental dysfunctions associated with dementia and schizophrenia.