Interleukin-6 as a possible regulator of intrafollicular Foxp3+ T cells in women undergoing IVF treatmen

• Khonina N.A.
• Andreeva E.A.
• Marina A. Tikhonova
• Batorov E.V.
• Alexandr A. Ostanin
• Pasman N.M.

Abstract

Regulatory Foxp3⁺ T cells (Treg) are involved in the induction of tolerance to fetal alloantigens and the formation of physiological immunosuppression during pregnancy. However, the mechanisms affecting their content, especially in the early stages of the reproductive process, remain unclear. This paper is devoted to the study of the relationship between the concentration of IL-6 and regulatory Foxp3⁺ T cells in the follicular fluid (FF) of women with different parameters of folliculo/oogenesis, blastulation and IVF outcomes. The study included 53 women with infertility undergoing IVF program. Collection of FF samples from dominant follicles was performed using transvaginal ultrasonic aspiration. The concentration of IL-6 in FF was assessed by flow fluorimetry (Bio-Plex Protein Assay System, Bio-Rad, USA). The relative content of CD4⁺Foxp3⁺ and CD4^-Foxp3⁺ T cells was assessed by flow cytometry.

The data obtained showed that increased IL-6 content in the FF is registered in women with a high number of follicles, oocytes, poor blastocyst quality and a negative IVF outcome. At the same time, the high content of IL-6 in FF is associated with a low number of intrafollicular CD4^-FoxP3⁺ cells, which inversely correlates with the concentration of IL-6. At the same time, the relationship of IL-6 with the number of CD4⁺FoxP3⁺ T cells was not detected. Thus, one of the reasons for the decrease in the number of CD4^-FoxP3+ cells that play a positive role in regulating early reproductive processes may be a high concentration of IL-6 in the FF.

Keywords:Foxp3+ T cells; IL-6; follicular fluid; IVF; infertility

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