Decreased human leukocyte antigen–DR expression in the lipid raft by peritoneal macrophages from women with endometriosis

ObjectiveTo investigate the macrophage response in endometriosis by determining the expression and localization of human leukocyte antigen (HLA)-ABC and HLA-DR by the peritoneal fluid (PF) macrophages and PF concentrations of interferon (IFN)-γ that regulate HLA expression.DesignCase-control study.SettingUniversity hospital.Patient(s)64 Japanese endometriosis patients, and 65 women with other laparoscopic diagnoses.Intervention(s)Venipuncture and laparoscopic peritoneal fluid collection.Main Outcome Measure(s)Expression and localization of HLA-ABC and HLA-DR in PF macrophages were determined by flow cytometry and confocal microscopy. The concentration of IFN-γ in PF was determined by enzyme-linked immunosorbent assay.Result(s)In women with endometriosis, expression of HLA-ABC and HLA-DR by PF macrophages, and the IFN-γ concentrations in PF were statistically significantly lower than in controls. Women with endometriosis showed a statistically significant positive correlation between HLA expression and IFN-γ concentration. By confocal microscopy, HLA-ABC was distributed homogenously on the macrophage surface whereas HLA-DR expression on these cells corresponded to the lipid raft.Conclusion(s)In women with endometriosis, low HLA expression and particularly reduced HLA-DR in the lipid raft may be influenced by low IFN-γ and may compromise antigen presentation, limiting the immune response to peritoneal cavity antigens such as implanted or metaplastic endometrial tissue.