Expression of the oestrogen and progesterone receptors on uterine mueosal leukocytes has
been examined by dual immunohistology. Neither the oestrogen receptor nor the
progesterone receptor was expressed by lymphocytes, macrophages or the distinctive
population of uterine natural killer (NK) cells. Although the accumulation and survival of
these NK cells appears to be hormonally dependent, the effects must therefore be indirect.