Problem: Activated lymphocytes can be eliminated by Fas/Fas ligand (FasL)-induced cell death. Endometrial cells express FasL. The aim of our study was to determine the expression of CD56+ cells (natural killer and natural killer T cells) Fas antigen CD95 and the early activation molecule CD69 in the peritoneal fluid of women with endometriosis.
Method: Two-colour flow cytometry was used.
Results: In the early stages of endometriosis, more CD56+ cells expressed CD69 and CD95 molecules when compared with the control group. However, in case of severe endometriosis the percentage of CD95+CD56+ cells in peritoneal fluid was similar to that of the control group, but the expression of CD69 molecules remained high.
Conclusion: Because of Fas/FasL mechanisms, in the initial stages of endometriosis the activated peritoneal fluid CD56+ cells can be intensively eliminated, thus providing conditions for the survival of ectopic endometrial cells and the development of the disease.