In our study, we found the Th1 cytokines such as IL-2, TNF-α and IFN-γ, have no difference between the chronic brucellosis and the healthy control groups, but the Th2 cytokines such as IL-10 and IL-6 in brucellosis group are significantly higher than these in control group (P<0.001). Here, IFNG is linked to brucellosis.