Human leukocyte antigen-G, a ligand for the natural killer receptor KIR2DL4, is expressed by eutopic endometrium only in the menstrual phase.
OBJECTIVE
To investigate menstrual cycle changes in expression by eutopic endometrium of a nonclassic human leukocyte antigen, HLA-G, which binds to the killer immunoglobulin-like receptor (KIR) 2DL4 (CD158d) on natural killer (NK) cells. Such antigens have been linked to endometriosis.


METHODS
Case-control study.


METHODS
University hospital.


METHODS
We examined 20 Japanese women undergoing hysterectomy for endometriosis and 17 undergoing hysterectomy for myoma.


METHODS
Immunohistochemical HLA-G staining of eutopic endometrium and peritoneal fluid (PF) cells from women with and without endometriosis. Flow cytometric analysis of PF NK cells from women with and without endometriosis.


METHODS
HLA-G staining in eutopic endometrium was quantified by image analysis. The KIR2DL4-expressing NK cells in PF were investigated by flow cytometry.


RESULTS
The HLA-G was expressed by eutopic endometrium only in the menstrual phase and not in the late proliferative or secretory endometrium. Intensity of HLA-G staining did not differ significantly between women with and without endometriosis. The HLA-G- expressing cells were detected in PF during the menstrual period. These cells are morphologically and flow cytometrically different from mesothelial cells and NK cells.


CONCLUSIONS
The HLA-G expression is observed in eutopic endometrium only during the menstrual phase, and no differences were observed between women with and without endometriosis. Epithelial cells bearing HLA-G may enter the peritoneal cavity during retrograde menstruation, allowing the antigen to react locally with KIR2DL4.
Kawashima
Masaaki
M
Department of Obstetrics and Gynecology, Kochi Medical School, Nankoku, Kochi, Japan. km501212km@hotmail.com
Maeda
Nagamasa
N
Adachi
Yoshihiro
Y
Takeuchi
Tamotsu
T
Yamamoto
Yorito
Y
Izumiya
Chiaki
C
Hayashi
Kazutoshi
K
Furihata
Mutsuo
M
Udaka
Keiko
K
Fukaya
Takao
T
D000328:Adult; D001202:Ascitic Fluid / Q000276:immunology*; D016022:Case-Control Studies; D004715:Endometriosis / Q000276:immunology* / Q000503:physiopathology / Q000601:surgery; D004717:Endometrium / Q000276:immunology* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D005434:Flow Cytometry; D006680:HLA Antigens / Q000032:analysis*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D006801:Humans; D007044:Hysterectomy; D007150:Immunohistochemistry; D007564:Japan; D007694:Killer Cells, Natural / Q000276:immunology*; D008597:Menstrual Cycle / Q000276:immunology*; D008875:Middle Aged; D054345:Receptors, KIR2DL4 / Q000032:analysis*
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; C515079:KIR2DL4 protein, human; D054345:Receptors, KIR2DL4