Evaluation of endometrial tissue specific complement activation in women with endometriosis.

OBJECTIVE

To determine if endometrial tissue specific complement (C) activation occurs in patients with endometriosis.

DESIGN

Prospective.

SETTING

University of Oklahoma Health Sciences Center, a tertiary care referral center.

PATIENTS

Twenty-six women, 9 with endometriosis and 17 without endometriosis.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Uterine and ectopic endometria were evaluated by the immunofluorescence assay for the presence of activated products of the initial (C3d) and terminal (C5b-9) C pathway, C3 regulatory proteins (decay-accelerating factor and membrane cofactor protein), and terminal C regulatory proteins (clusterin and vitronectin).

RESULTS

The initial (C3d) and terminal (C5b-9) C components were deposited on blood vessel walls in uterine and/or ectopic endometria of women with and without endometriosis. In the stromal compartment at both sites, C deposition was colocalized with terminal C inhibitors/cell-cell attachment factors, clusterin and vitronectin on elastic fibers. No specific staining for C proteins was detected on the glandular epithelium of uterine and ectopic endometrial tissues examined. Furthermore, intense staining of endometrial epithelium for C3 regulatory proteins, decay-accelerating factor, and membrane cofactor protein was noted on endometrial glands from women with and without endometriosis.

CONCLUSIONS

Our findings demonstrate a lack of specific deposition of C in the glandular epithelial cells of endometria of women with endometriosis. The localization of C3 regulatory proteins, decay-accelerating factor, and membrane cofactor protein on glandular epithelium may suggest the involvement of intrinsic protective mechanisms on these cells from autologous C attack in vivo.