Histocompatibility leukocyte antigen-G is not expressed by endometriosis or endometrial tissue.
OBJECTIVE
The immunological mechanisms that support persistence and proliferation of ectopic endometrial implants within the peritoneal cavity of women with endometriosis are unknown. Inhibition of natural killer (NK) and cytotoxic T-cell function has been proposed as a mechanism. We tested the hypothesis that expression of a nonclassical major histocompatibility antigen, HLA-G, might explain the local immunosuppression associated with ectopic endometrium.


METHODS
Nested case-control study of women with and without laparoscopic evidence of endometriosis.


METHODS
Reproductive endocrinology clinic at a university hospital.


METHODS
Peritoneal fluid specimens from 10 women with revised AFS stage I-IV endometriosis and from 10 age-matched normal controls without laparoscopic evidence of endometriosis were tested for the presence of HLA-G protein. Endometriosis and normal endometrial biopsies from four patients were used to prepare stromal cell cultures directly evaluated for HLA-G protein.


METHODS
None.


METHODS
The expression of HLA-G in peritoneal fluid, tissue, and cell cultures was determined by immunoblotting with a specific monoclonal antibody.


RESULTS
HLA-G protein was not detectable in peritoneal fluid specimens of endometriosis patients or controls. Moreover, ectopic and normal endometrial tissues and stromal cells did not express HLA-G.


CONCLUSIONS
Immune cell inhibition in endometriosis must be mediated by factors other than HLA-G.
Hornung
D
D
Center for Reproductive Sciences, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, California 94143-0556, USA.
Fujii
E
E
Lim
K H
KH
Vigne
J L
JL
McMaster
M T
MT
Taylor
R N
RN
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D001202:Ascitic Fluid / Q000276:immunology; D015153:Blotting, Western; D016022:Case-Control Studies; D002478:Cells, Cultured; D002822:Choriocarcinoma / Q000276:immunology; D004715:Endometriosis / Q000276:immunology* / Q000473:pathology; D004717:Endometrium / Q000166:cytology / Q000276:immunology* / Q000473:pathology; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D005260:Female; D006680:HLA Antigens / Q000032:analysis*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D006801:Humans; D010535:Laparoscopy; D008969:Molecular Sequence Data; D012016:Reference Values; D017154:Stromal Cells / Q000166:cytology / Q000276:immunology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000939:Epitopes; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I