Abstract: 　[ Abstract] 　Objective: To investigate the relationship between expression ofTh1/Th2 types cytokines( IFN-γ, TNF-β、IL-10、IL-4) mRNA in PBMC of the patients with alopecia areata; to investigate their roles in the pathogenesis of AA..Methods:Apply RT-PCR technique to detect the mRNA expression ofTh1 types cytokines（ IFN-γ、 TNF-β）、Th2 types cytokines （IL-10、IL-4）in PBMC of the patients with alopecia areata stimulated by PHA. Results:The mRNA expression of Th1 type cytokines in PHA-stimulated PBMC of the patients with localized alopecia areata patients were increased compared with healthy controls(P<0. 05), the mRNA expression of Th2 type cytokines(IL-4、 IL-10) were decreased compared with healthy controls (P<0. 05). the patients with extensive alopecia areata were increased compared with healthy controls (P<0. 01)and localized AA (P<0. 05), the mRNA expression ofTh2 type cytokines (IL-4、IL-10) were decreased compared with healthy controls and localized AA. (P<0. 05) Conclusion：the expression of Th1/Th2 types cytokines were unbalance in AA.there were over-expression of Th1 type cytokines in the PBMC of alopecia areata ,this may play an important role in pathogenesis of AA. Keywords: alopecia areata; cytokines ； gene expression ； IFN-γ、；TNF-β； IL-4；、 IL-10；PBMC.

Key words: alopecia areata, cytokines