The effects of Ginkgo biloba extract added to haloperidol on peripheral T cell subsets in drug-free schizophrenia: a double-blind, placebo-controlled trial.
OBJECTIVE
To investigate the effects of Ginkgo biloba extract (EGb) administration on T lymphocyte subsets and superoxide dismutase (SOD) levels in schizophrenia.


METHODS
One hundred and nine schizophrenic inpatients were randomly assigned to 12 weeks of treatment with 360 mg/day of EGb plus a stable dose of 0.25 mg kg(-1) day(-1) of haloperidol and placebo plus the same dose of haloperidol using a double-blind design. Clinical efficacy was determined using the Brief Psychiatric Rating Scale (BPRS), Scale for Assessment of Positive Symptoms, and Scale for Assessment of Negative Symptoms. T lymphocytes (CD3+), T helper cells (CD4+), T suppressor cells (CD8+), and IL-2-secreting cells were measured using the alkaline phosphatase/antialkaline phosphatase technique; and SOD levels were measured by radioimmunometric assay at baseline and at posttreatment, as compared to 30 sex- and age-matched normal subjects.


RESULTS
Patients demonstrated significantly lower CD3+, CD4+, and IL-2-secreting cells, together with CD4/CD8 ratio, and significantly higher blood SOD levels than did healthy controls at baseline. There was a significantly negative relationship between SOD and CD4+ cells in the schizophrenic group at baseline. After a 12-week treatment, CD3+, CD4+, and IL-2-secreting cells, together with CD4/CD8 ratio, showed a significant increase, but a significant decrease in SOD levels in the EGb group. There was only a significant increase in CD4+ cells but no change in SOD levels in the placebo group. There was a significant correlation between the change in CD4+ cells at posttreatment vs pretreatment and a reduction of BPRS total score in the whole patient group.


CONCLUSIONS
EGb may improve the decreased peripheral immune functions in schizophrenia. The beneficial effects of EGb on the immune systems and the improvement of schizophrenic symptoms may be medicated through its antioxidant activity.
Zhang
Xiang Yang
XY
Institute of Mental Health, Peking University, Beijing, 100083, People's Republic of China. xyzhang@bcm.edu
Zhou
Dong Feng
DF
Cao
Lian Yuan
LY
Wu
Gui Ying
GY
D000328:Adult; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use*; D014150:Antipsychotic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D010054:Brief Psychiatric Rating Scale; D017252:CD3 Complex / Q000032:analysis; D018791:CD4 Lymphocyte Count; D016516:CD4-CD8 Ratio; D002908:Chronic Disease; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D020441:Ginkgo biloba; D006220:Haloperidol / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology; D012565:Schizophrenic Psychology; D013482:Superoxide Dismutase / Q000097:blood; D016176:T-Lymphocyte Subsets / Q000187:drug effects*; D013997:Time Factors; D016896:Treatment Outcome
D000975:Antioxidants; D014150:Antipsychotic Agents; D017252:CD3 Complex; D004365:Drugs, Chinese Herbal; C508594:IL2 protein, human; D007376:Interleukin-2; D013482:Superoxide Dismutase; D006220:Haloperidol