Characterisation of dendritic cell subsets in chronically inflamed human epididymis

Infection and inflammation of the genital tract are thought to be a primary aetiological factor of male infertility. Chronic epididymitis appears to be more important than prostatitis or seminal vesiculitis due to the direct interaction between sperm cells and epididymal epithelium. Dendritic cells (DCs) are a heterogeneous population of antigen-presenting cells that play a crucial role in the regulation of the immune response and immunological tolerance. The aim of this study was to investigate the expression and characteristic of different DC subsets in chronic inflammation of human epididymis and controls. Our study demonstrated that normal human epididymis contained only immature CD1a(+) DCs, CD11c(+) myeloid DCs (mDCs) and CD209(+) DCs whereas CD123(+) plasmacytoid DCs and CD83(+) mature DCs were virtually absent. The number of both CD11c(+) IL-23(+) mDCs and CD123(+) pDCs were significantly elevated in inflamed epididymis; meanwhile the mDC populations of CD1a(+), CD209(+) immature DCs and CD83(+) mature DCs also increased in inflamed group. Moreover, Th17 (CD4(+) IL-17(+)) cells were predominantly distributed under chronic inflammation of human epididymis. Taken together these results suggest that epididymal DCs might play a pivotal role in the development of chronic epididymitis and induce an increased recruitment of Th17 cells under inflammatory conditions.