Transitional Lesions, One More Step Towards Understanding the Pathogenesis of Adenomyosis

Area of Science:

• Gynecology
• Immunology
• Pathology

Background:

• Adenomyosis is a benign gynecological disorder linked to abnormal uterine bleeding, dysmenorrhea, and subfertility.
• Its pathogenesis remains unclear, with the tissue injury and repair (TIAR) mechanism widely accepted.
• Immune system involvement is suspected but requires clarification due to inconsistent findings.

Purpose of the Study:

• To investigate immune cell phenotypes in adenomyotic uteri using a novel multiplex technique.
• To analyze immune cell distribution across different menstrual cycle phases in adenomyosis.
• To elucidate the role of immune cells in adenomyosis pathogenesis.

Main Methods:

• Immunohistochemistry and multiplex immunofluorescence were employed.
• Immune cell populations were analyzed in 30 adenomyotic and 15 healthy hysterectomy samples.
• Samples were evaluated based on menstrual cycle phase.

Main Results:

• Adenomyotic and transitional lesions showed reduced immune infiltrates (T cells, NK cells, B cells, macrophages, dendritic cells) compared to eutopic endometrium.
• Mast cells were significantly increased in transitional adenomyotic lesions.
• Transitional lesions indicated the progressive nature of adenomyosis.

Conclusions:

• Mast cells are implicated in adenomyosis development, pain, tissue remodeling, angiogenesis, and neurogenic inflammation.
• Findings support the TIAR hypothesis and highlight the progressive nature of adenomyosis.
• Further research into immune-targeted therapies for adenomyosis is warranted.