Cyclic variation of major histocompatibility complex class II antigen expression in the human fallopian tube epithelium.

Objective: To systematically investigate the expression of major histocompatibility complex (MHC) class II antigens (human leukocyte antigens, HLA-DR, -DP, and -DQ) on columnar epithelium in the fallopian tube during the menstrual cycle.

Study Design: Biopsies were collected from the fallopian tube during laparotomy sterilization and immunoperoxidase staining was performed.

Settings: Departments of Gynecology and Obstetrics and Clinical Immunology and Transfusion Medicine, Uppsala University, Uppsala, Sweden.

Patients: Twenty healthy fertile women undergoing sterilization at different times of the menstrual cycle.

Interventions: None.

Main Outcome Measures: The staining of the columnar epithelium was judged on a 4-graded scale according to the distribution of class II antigens.

Results: A widespread preovulatory HLA-DR expression was observed almost completely lining the columnar epithelial cells including the luminal surface, whereas postovulatory the HLA-DR expression was withdrawn from the surface. The HLA-DP and -DQ antigens varied in a similar way, although not as pronounced.

Conclusions: The MHC class II antigen variation in the fallopian tube epithelium seen in this study may indicate a hormonal regulation that could reflect variable need for local immunocompetence during the menstrual cycle: a preovulatory need for immunoreactivity against invading microbes and postovulatory an optimal survival of the foreign preimplantation embryo.