The possible role of plasma kallikrein-kinin system and leukocyte elastase in pathogenesis of schizophrenia

The main purpose of this paper is to study the possible causes of blood-brain barrier (BBB) damage during the acute condition of schizophrenia (Sch), which makes brain antigens accessible to the immunocompetent cells. The development of autoimmune reactions in this disease has to be preceded by the damage of BBB. We have studied the level of activity of plasma kallikrein-kinin (KKS) and complement systems, C-reactive protein (CRP) concentration, proteinase inhibitory potential as well as the oxidized and degranulating activity of neutrophils as the main factors affected the permeability of tissue-blood barrier. Our results suggested that the acute stage of Sch was accompanied by the activation of KKS on the background of enhance in the functional activity of the alpha-1-proteinase inhibitor. The increased level of CRP, the high haemolytic activity of complement and significant degranulating activity of polymorphonuclear leukocytes testified to inflammatory character of Sch. The treatment with psychotropic drugs have led to decrease of polymorphonuclear elastase (PMN-E) activity in patient's plasma. Our in vitro study indicates that Haloperidol causes the lowering of PMN-E activity in the dose-dependent fashion.