The assessment of epididymal lymphatics within the concept of immunologically privileged sites

This paper seeks to provide background information for future studies of immunological responses in the epididymis. Immunologically privileged sites afford anomalous protection to foreign grafts and this is usually thought to be related to absence of intrinsic lymphatics. A search through the literature reveals lack of any attempt to implant foreign tissue into this organ. The present investigation was undertaken to consider the presence, if any, of lymphatic channels within the connective tissue framework of rat epididymis. The tissues were taken through for histology and examined with light and electron microscopes. Contrary to anticipation, there are abundant lymphatic channels within the epididymal tissue. In the discussion a hypothesis is raised that the epididymis may not be an immunologically privileged site or that if any privilege, the explanation will not be related to absence of terminal lymphatics in this area. Further work in progress seeks to clarify this hypothesis.