A. Hameed et al., PERFORIN EXPRESSION IN ENDOMETRIUM DURING THE MENSTRUAL-CYCLE, International journal of gynecological pathology, 14(2), 1995, pp. 143-150
Perforin is a marker of functionally active cytotoxic T lymphocytes (C
TLs) and natural killer (NK) cells. We examined perforin expression in
endometrium throughout the menstrual cycle. In addition, perforin exp
ression was studied in endometrial leukocytes in women with anovulator
y cycles with or without progesterone therapy and in postmenopausal wo
men. In the endometrium, perforin-positive endometrial lymphocytes inc
reased in numbers in the middle through late secretory phases. In wome
n with anovulatory cycles, the proliferative endometrium, before estro
gen withdrawal endometrial breakdown, contained less perforin-positive
lymphocytes compared with the premenstrual endometrium of the normal
menstrual cycle. The progestin-induced endometrial decidualization was
accompanied by an extensive recruitment of perforin-positive cells. I
n contrast, the postmenopausal atrophic endometrium showed complete ab
sence of perforin-positive cells. The lymphocytes isolated from secret
ory endometrium were CD3(-), CD56(+) (similar to 80%) or CD3(+), CD8() T-cell receptor (TCR)-gamma delta(-) (similar to 20%). Almost 90% +/
- 5.5 of the CD3(-), CD56(+), and up to 25% +/- 7% of CD8(+) T lymphoc
ytes contained perforin. Perforin expression was further confirmed in
endometrial lymphocytes by Northern blot analysis. In vitro, isolated
endometrial lymphocytes exhibited NK-like cytotoxicity, After cyclic h
ormone withdrawal during normal menstrual cycle, these perforin-positi
ve cytotoxic cells may be involved in endometrial stromal breakdown du
ring menstruation.