Objective:In order to demonstrate the role of Th1/Th2 lymphocyte imbalance in the mechanism of alopecia areata(AA)and the relationship between Th1 function and AA.Methods:Forty-five AA patients and 25 healthy children(control group) were involved in the study.According to the extent of the disease

all involved patients were then divided into 2 groups:LAA group(35 localized alopecia areata patients)

and AT/AU group(10 alopecia totalis or alopecia universalis patients).IFN-γ

IL-12

IL-4 and IL-10 levels were detected using Enzyme-linked immunosorbent assay(ELISA) in childhood alopecia areata before and after 3 months treatment.Results:①The balance of Th1/Th2 was disturbed in childhood alopecia areata.The serum levels of IFN-γwere significantly increased in the AA patients compared to the the levels in control group

and the level of AT/AU patients was higher than LAA patients.The level of IL-12 in AT/AU group had significant difference between patients and control

but there wan no significant difference in LAA group.In addition

the difference related to the IL-4 and IL-10 levels was not significant.②The level of serum IFN-γin AA patients were significantly decreased after the treatment of BCG-PSN;and the result of serum IL-12 in LAA group was same to IFN-γ

but AT/AU patients had no significant difference.While no difference on the IL-4 and IL-10 levels between before and after the treatment significantly.③The serum IFN-γ levels had a positive correlationship with the serum IL-10 levels.Conclusions:①Th1/Th2 immunoregulation disturbance was related with the occurrence of AA

characterized by Th1 lymphocyte hyperaction.The onset of the disease was regulated by the Th1 cytokines

and IFN-γand IL-12 probably played a leading role.②The serum levels of IFN-γand IL-12 could be used as indicators of the extent of the disease.