Chronic inflammatory conditions of the male reproductive tract are thought to be a primary etiological factor in male infertility.The epididymis is considered to be the most common site of intrascrotal inflammation and a significant cause of male fertility disorders rather than the prostate or seminal vesicles.The purpose of the present study was to identify the distribution of DCs of various phenotypes in control and chronically inflamed human epididymis.Immunohistochemistry and immunofluorescence of double staining were performed at control and inflammatory group.The results showed that (Ⅰ) normal human epididymis contained only immature intraepithelial LCs, interstitial CD1 lc, and CD209 DCs whereas CD123pDCs and CD83 mature DCs were virtually absent;(Ⅱ) the number of both CD11cIL-23 mDCs and CD 123IFN-αpDCs were significandy elevated in inflamed epididymis;(Ⅲ) the mDC populations of Cdla, CD209 immature DCs and CD83mature DCs also increased in inflamed group;(Ⅳ) Th17 (CD4IL-17) cells were predominantly distributed under chronic inflammation of human epididymis.Our results indicate that, under inflammatory conditions, the modified actions of different DC subpopulation induce autoimmune response and promote Th 17 cells polarization.