SELECTIVE LOCALIZATION OF INTERLEUKIN-1 RECEPTOR ANTAGONIST IN EUTOPIC ENDOMETRIUM AND ENDOMETRIOTIC IMPLANTS

Objectives: To determine whether interleukin-1 receptor antagonist (IL -1ra) expression was concordant in eutopic endometrium and endometriot ic implants. Design: Paired samples of endometrium and endometriotic i mplants from eight patients with endometriosis were used. Main Outcome Measures: Interleukin-1 receptor antagonist was demonstrated immunohi stochemically on frozen sections of eutopic and ectopic endometria. A sandwich technique with polyclonal rabbit anti-IL-1ra antibody and an avidin-biotin reagent (Vector Laboratories, Inc. Burlingame, CA) was u sed. Results: Seven of eight (88%) eutopic endometrial sections reveal ed staining of glandular epithelium with complete absence of any stain ing of the stromal compartment. In the counterpart sections of endomet riosis, the glandular as well as the stromal compartments were negativ e for IL-1ra in all patients. Conclusion: These data suggest a differe ntial production of the IL-1ra in eutopic endometrium and endometrioti c implants. The potential clinical implications of this finding are di scussed.