Polymorphonuclear leukocytes in the endometrium during the normal menstrual cycle

Area of Science:

• Reproductive biology
• Gynecology
• Histopathology

Background:

• The endometrium undergoes cyclical changes.
• The role of immune cells, specifically polymorphonuclear leukocytes (PMNs), in normal endometrial tissue is not fully elucidated.
• Understanding PMN presence is crucial for interpreting endometrial pathology.

Purpose of the Study:

• To investigate the presence and distribution of PMNs in normal endometrium throughout the menstrual cycle.
• To compare the efficacy of Hematoxylin and eosin (H&E) and chloroacetate esterase (CAE) stains in detecting PMNs.
• To differentiate PMNs from endometrial granulocytes.

Main Methods:

• Review of 100 endometrial curettage and biopsy specimens stained with H&E for dating and PMN presence.
• Quantification of PMNs using CAE stains.
• Histological examination to identify and differentiate cell types.

Main Results:

• PMNs were found in large numbers in areas of tissue degradation, specifically in day 28 and menstrual phase endometrium.
• PMNs were present in small numbers in intact endometrial tissue across the cycle.
• Both CAE and H&E stains demonstrated similar efficacy in PMN detection.
• CAE staining clearly distinguished PMNs from endometrial granulocytes, which did not stain.

Conclusions:

• PMN presence in the endometrium is primarily associated with tissue degradation and the menstrual phase.
• H&E and CAE staining are both reliable methods for PMN identification.
• CAE staining provides a specific marker for differentiating PMNs from endometrial granulocytes.