Oral Presentation ESA-SRB-NZSE-CaSR 2026 in conjunction with ENSA

Peritoneal fluid (PF)-derived small extracellular vesicles (sEVs) drive T cell activation in endometriosis. (142991)

Claire Davison 1 2 , Anna Tresso 2 , Johanna K Farley 1 2 , Natasha Borash 1 2 , Chloe James 1 2 , Niharika Thota 1 2 , Shima Bayat 1 , Beverley Vollenhoven 1 3 , Thomas T Tapmeier 1 2
  1. Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
  2. The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
  3. Women and Newborn's Program, Monash Health, Clayton, Victoria, Australia

Background

Endometriosis is a chronic, inflammatory disorder where endometrial-like tissue grows outside of the uterus affecting >10% of AFAB (assigned female at birth) people of reproductive age (1). 47% of infertile AFAB people suffer from endometriosis (2).

sEVs from endometrial epithelial cells facilitate embryo implantation and growth (3). sEVs from the PF carry specific protein cargo and may prepare a pre-implantation niche for lesions, similar to tumour metastasis (4,5). Therefore, the beneficial role of sEVs in pregnancy may have a pathogenic effect in endometriosis.

 

We hypothesise that sEVs skew peritoneal immunotolerance to facilitate lesion growth.

  

Methods

PF was obtained following informed consent from patients undergoing laparoscopic surgery at Monash Health locations (2021-2025, n=102) (Monash Health HREC 20-0000-159A). Menstrual cycle phase was determined via endometrial biopsy. Disease state was determined by surgical observation and histological analysis. Cells were separated from PF using centrifugation (300xg), and sEVs via differential ultracentrifugation (100,000xg), sized by nanoparticle tracking analysis, and EV-associated protein was quantified.

 

T cells (Jurkat) were treated with 1μg/ml of neat PF-derived sEVs from endometriosis (n=5) and control (n=5) patients in EV-free medium (24h). Activation and skewing were determined using qRT-PCR; GATA3, T-bet, RORγT, FOXP3, CLEC5A, CD163L1. Full spectrum flow cytometry was conducted on matched sample PF cells (endometriosis n=4, control n=3). Data were analysed using Graphpad Prism 11.0.2; p<0.05 deemed significant (Mann-Whitney test).

 

Results

Treatment with endometriosis-patient derived EVs induced possible (p=0.0556) upregulation of CCR7 and downregulation of GATA3 (p=0.0556) expression compared to control sEVs. A concomitant decrease in tissue resident CD4+ T cells (CD45+CD3+CD4+CD8-CD69+CD38-) was observed in the PF of endometriosis patients compared to controls (p=0.0571).

 

Conclusion

We hypothesise the increased expression of CCR7 in T cells from the PF of endometriosis patients allows localisation and expansion of endometriosis-associated T cells in the lymph nodes, exacerbating the inflammatory environment in endometriosis.