Comparison of RCAS1 and metallothionein expression and the presence and activity of immune cells in human ovarian and abdominal wall endometriomas

Abstract

Background: The coexistence of endometrial and immune cells during decidualization is preserved by the ability of endometrial cells to regulate the cytotoxic immune activity and their capability to be resistant to immune-mediated apoptosis. These phenomena enable the survival of endometrial ectopic cells. RCAS1 is responsible for regulation of cytotoxic activity. Metallothionein expression seems to protect endometrial cells against apoptosis. The aim of the present study was to evaluate RCAS1 and metallothionein expression in human ovarian and scar endometriomas in relation to the presence of immune cells and their activity.

Methods: Metallothionein, RCAS1, CD25, CD69, CD56, CD16, CD68 antigen expression was assessed by immunohistochemistry in ovarian and scar endometriomas tissue samples which were obtained from 33 patients. The secretory endometrium was used as a control group (15 patients).

Results: The lowest metallothionein expression was revealed in ovarian endometriomas in comparison to scar endometriomas and to the control group. RCAS1 expression was at the highest level in the secretory endometrium and it was at comparable levels in ovarian and scar endometriomas. Similarly, the number of CD56-positive cells was lower in scar and ovarian endometriomas than in the secretory endometrium. The highest number of macrophages was found in ovarian endometriomas. RCAS1-positive macrophages were observed only in ovarian endometriomas. CD25 and CD69 antigen expression was higher in scar and ovarian endometriomas than in the control group.

Conclusion: The expression of RCAS1 and metallothionein by endometrial cells may favor the persistence of these cells in ectopic localization both in scar following cesarean section and in ovarian endometriosis.

Figure 1

RCAS1 expression in: scar endometriomas (A,B), ovarian endometriomas (C,D) and secretory endometrium (E,F). A – Weak positive glandular reaction in scar endometrioma (horizontal arrows). Obj. magn. ×40; B-Very weak immunoreactivity in glandular epithelium in scar endometrioma (horizontal arrow). Obj. magn. ×40; C – Weak immunoreactivity in glandular epithelium of ovarian endometrioma (horizontal arrow). Obj. magn. ×60; D – Strong immunoreactivity in glandular epithelium of ovarian endometrioma (horizontal arrows). Obj. magn. ×60; E – Strong immunoreactivity in glandular epithelium of the secretory endometrium, also of its basal part (horizontal arrows). Obj. magn. ×10; F – Strong immunoreactivity in glandular epithelium of secretory endometrium (horizontal arrow). Obj. magn. ×40.

Figure 2

MT expression in: scar endometriomas (A,B), ovarian endometriomas (C,D) and secretory endmetrium (E,F). A – Moderate positive stromal reaction in scar endometrioma tissue (vertical arrows). Obj. magn. ×40; B-Strong immunoreactivity in glandular epithelium of scar endometrioma (horizontal arrow) Obj. magn. ×10; C – Moderate immunoreacitvity in stromal cells of ovarian endometrioma (vertical arrows). Obj. magn. ×40; D – Very weak immunoreactivity in glandular epithelium of ovarian endometrioma (vertical arrows). Obj. magn. ×40; E – Strong immunoreactivity in glandular epithelium of secretory endometrium (horizontal arrows) and negative stromal cells (x). Obj. magn. ×40. F – Strong MT immunoreactivity in glandular epithelium of the secretory endometrium (horizontal arrow). Obj. magn. ×60.

Figure 3

Destroyed epithelial layer of an endometrial ovarian cyst. The covering of it composed mainly of macrophages, with strong RCAS1 expression (B, C, D). RCAS1-positive macrophages present also loosely in the cyst fluid (A). Obj magn.: A, C, D ×40; B ×20.