Serum level of interleukin-6 associated with the dose of clozapine and amelioration of symptoms in female patients with first-episode schizophrenia

Jianqiang XU; Luxian Lü; Yuzhong SHI

ABSTRACT

BACKGROUND:

Interleukin-6 (IL-6) is a cytokine produced in the process of organic immune activities. The problems still need further exploration, including whether the changes of serum level of IL-6 after clozapine treatment ware induced directly by the drug, and whether IL-6 is directly correlated with the changes of the psychiatric symptoms in female patients.with first-episode schizophrenia.

OBJECTIVE:

To explore the changes of the serum level of IL-6 and its relation with the dose of clozapine and the amelioration of the symptoms in female patients with first-episode schizophrenia.

DESIGN:

A non-randomized case-control observation synchronically.

SETTING:

Department of Psychiatry, Second Affiliated Hospital of Xinxiang Medical College.

PARTICIPANTS:

Twenty female patients with first-episode schizophrenia (patient group) were selected from Henan Psychiatric Hospital. They all met the diagnostic standards of schizophrenia in the 3rd edition of Chinese Classification and diagnostic criteria of Mental Disorders (CCMD-3), their score of positive and negative syndrome scale (PANSS)was above 60 points, and had not been treated or at least not taking medicine for 2 weeks during clinical treatment.Patients with physical disease, endocrine and immune system diseases, malnutrition and other mental problems, those with the history of being allergic and hormone treatment, those receiving immune pharmaceutical treatment, and recently having been vaccinated preventively, and the pregnant and breast-feeding women were excluded. Twenty healthy female volunteers, who had no significnat difference in age and gender from the subjects in the patient group,were taken as the control group, and the exclusive standards were the same as those in the patient group. All the subjects were enrolled with the approval of themselves and their guardians.

METHODS:

All the patients were adminsitrated with clozapine only, with the dose being added by 25-50 mg per day,and the maximal dose was reached within 3 weeks. The principle for the administration was the maximal effectiveness and the minimal side effect. ① Serum level of IL-6 in the patient group was detected using enzyme-linked immunoabsorbent assay (ELISA) before treatment and at 1, 2 and 4 weeks after treatment respectively. ② High performance liquid chromatography (HPLC) was used to determine the content of clozapine, and the levels of IL-6 in serum of the controls were taken as controls. ③ Correlations were analyzed in the patient group between the serum level of IL-6 before treatment and at 1, 2 and 4 weeks after treatment and the PANSS scores (scores of positive and negative symptoms, and general pathology, and the total score) at corresponding time points.MATN OUTCOME

MEASURES:

① Serum levels of IL-6 before treatment and at each time point after treatment; ②Correlation analysis between the serum levels of IL-6 and clozapine content; ③ Correlation analysis between changes of schizophrenic symptoms and serum levels of IL-6.

RESULTS:

① Serum level of IL-6 before treatment in the patient group was significantly higher than that in the control group [(137.72±18.84), (65.05±20.95) ng/L, t =11.53, P ＜ 0.01], those in the patient group at 1, 2 and 4 weeks after treatment were significantly lower than that in the control group [(28.11±5.42), (8.48±1.14), (13.90±2.55), (65.05±20.95) ng/L, t =7.63, 12.01, 10.84, P ＜ 0.01]. ② Correlation analysis between the serum levels of IL-6 and clozapine content The results showed that the serum level of IL-6 had no significant correlation with the clozapine content at 1, 2and 4 weeks after treatment (r =-0.15, 0.12, -0.29, P ＞ 0.05). ③ Correlation analysis between IL-6 level and schizophrenic symptoms In the patient group, there was significant positive correlation before treatment between the serum level of IL-6 and the score of positive symptoms (r=0.386, P＜ 0.01), and there was no significant correlation between the serum level of IL-6 and the total scores of PANSS and each factor scores at 1, 2 and 4 weeks after treatment (r=0.136-0.237, P ＞ 0.05).

CONCLUSION:

The serum level of IL-6 in female patients with first-episode schizophrenia was higher than that in healthy females, and it could be decreased by clozapine, and the amelioration of the schizophrenic symptoms had no significant correlation with the changes of IL-6 levels.