White cells and the ovary – incidental invaders or essential effectors?

While the disciplines of reproduction and immunology have traditionally been seen to be discrete and separate areas of biology, there is now compelling evidence of an intimate relationship between the cells of the reproductive tract and those of the immune system. White cells are found throughout the uterus, Fallopian tubes and ovary, and change in numbers and subtypes throughout the reproductive cycle (Bulmer et al. 1991). In the uterus, leukocytes congregate at the implantation site and successful conception leads to alteration of the maternal immune system (Hill 1990). For clinical purposes, the importance of immune activation is identified in two relevant hypotheses. The first, the immunotrophism hypothesis of Wegmann and colleagues (Wegmann 1988, Beaman 1990), states that products of T lymphocytes in the uterus promote implantation and embryonic development through stimulation of the proliferation and function of the trophoblast cells. The second, promoted by Hill (1990) and termed the immunodystrophism