Study On The Plasma Levels Of IL-6, SIL-6R And IL-13 In First-episode Schizophrenic Patients

Interleukines(IL) are important cytokines(CK) produced by lymphocyte, monocyte or other non-monocyte. They participate in many course of physiology and pathology.Previous findings have suggested that plasma level of IL-6 obviously increase in schizophrenia. The reason of increase perhaps correlated with the function of dopamine. The association between soluble interleukine-6 receptor(sIL-6R) and schizophrenia which has been reported abroad shows difference. The relationship between IL-13 in plasma and schizophrenia has been not reported up to now. The objects of this study was to examine the changes of plasma IL-6, sIL-6R and IL-13 in schizophrenia and their relationship with psychopathology. Thirty first-episode patients who all fulfilled Chinese Classification and Diagnostic Criteria of Mental Disorders (CCMD-3) for schizophrenia were measured for plasma levels of IL-6,sIL-6R and IL-13 with enzyme linked immunosorbent assay(ELISA) before and after treatment. All patients were treated by clozapine. They were compared with 28 normal controls. At the same time, the positive and negative syndrome scale(PANSS) was used to evaluate psychotic symptoms before and after drug treatment. Then all the data were analyzed with Statistical Package for the Social Science(SPSS 8.0)The results were showed as follow:1.Plasma level of IL-6 was significantly higher in schizophrenic patients than in normal controls before and after treatment(P<0.05). Compared to the patients before drug treatment, the level of IL-6 was higher(P<0.05).2.The sIL-6R level was significantly higher in schizophrenic patient than normal controls before drug treatment(P<0.05), and it significantly decreased after treatment(P<0.05).3.The IL-13 level was significantly lower in patient than in normal controls before drug treatment(P<0.05), and it increased towards normal controls after treatment(P>0.05).4.Correlation and regression analysis have shown that the increased extend of plasma IL-6 level after drug treatment was positively correlated with dosage of clozapine. There were a positive correlation between sIL-6R level and positive syndrome, and a negative correlation between IL-13 level and negative syndrome. The marked negative correlation were found between IL-13 level and PANSS total score and positive correlation between the increased extent of IL-13 level and the decreased extent of negative syndrome.5.There was no correlation among plasma levels of IL-6,sIL-6R and IL-13 in schizophrenic patients and normal controls.The results of this study suggests the possible ofimmunological dysfunction in the schizophrenic patients.PlasmaIL-6 level in schizophrenic patients was significiantly higherthan mormal controls and it had no relation to age-at-onset and duration.the increaseed extent of plasma IL-6 level after drug treatment was positively correlated with dosage of clozapine.The mechanism may be clozapine hasins immunosuppressive effects by altering plasma IL-6 level.Plasma sIL-6R level was significantly higher than normal controls before treatment and it positively relate to positive syndrome.We regard it's mechanism is in close relationship with plasma IL-6 which can improve the activity of dopamine and 5-HT.Plasma IL-13 can suppress the production of plasma IL-6 in normal person,but plasma IL-13 was significantly decreased and plasma IL-6 significantly increased in schizophrenic patieents .This may be one of the reasons which cause psychopathology. The Study showed the positivly correlation between the increased plasma IL-13 and the deccreased extent of negative syndrome.lt suggests that plasma IL-13 restored to normal following after the improvement of negative syndrome.Whether plasma IL-13 can be the immune marker of negative syndrome in schizophrenia need further studies.