O-265 Increased CD8+ T-cell exhaustion due to high NKG2A/HLA-E engagement and IL-15 induction in adenomyosis
Authors: Jiao X , Liu W , Sheng S , Zhu C , Wang F 
Published: June 2023

Abstract

Study question
Is there dysregulation of immune cells in the local uterine microenvironment of patients with adenomyosis? If any, what’s the underlying mediators and mechanisms?

Summary answer
Increased CD8+ T-cell exhaustion due to enhanced HLA-E/NKG2A engagement and IL-15 induction in ectopic adenomyotic lesions existed in human patients and mice models with adenomyosis.

What is known already
The immunological dysfunction has long been considered in the pathogenesis of adenomyosis. However, high heterogeneity in immune cell alterations and contradictory results were reported due to the technique limitation of immunohistochemistry mainly used in previous studies. A comprehensive picture of the dysregulation of immune cells in the local uterine microenvironment of patients with adenomyosis is still lacking. Specially, increased number of CD8+ T cells have been reported in adenomyotic patients, whether functional deficiency of CD8+ T cells may contribute to the abnormal accumulation and residency of ectopic endometrial cells at pathological sites remains unknown.

Study design, size, duration
The paired ectopic lesions and eutopic endometrium from 80 patients with adenomyosis, and normal endometrium and myometrium from 62 patients with uterine myoma (controls) were collected between 2021 to 2022. Mice models with adenomyosis by neonatal tamoxifen treatment were established for experiments in 2022.

Participants/materials, setting, methods
The alteration of immune subsets, NKG2A expression, exhausted phenotypes and CD8+ T-cell dysfunction by flow cytometry, the expression/localization of HLA-E and IL-15 by immunohistochemistry were investigated in uterine tissues of patients and mice models with adenomyosis. CD8+ T cells were sorted, and in-vitro cultured with recombinant human transforming growth factor-β (rhTGF-β) or rhIL-15 to determine the NKG2A expression. Correlation analyses were conducted for association between immune disturbances and disease severity (dysmenorrhea, local/diffuse lesion, CA125 level).

Main results and the role of chance
We found that an increase in CD8+ T cell number was the predominant alteration in ectopic lesions in patients with adenomyosis, and it was significantly associated with the severity of adenomyosis. For CD8+ T cells in adenomyotic lesions, the expression of NKG2A was positively correlated with CD94 expression, and CD94/NKG2A mainly enriched on CD103+ tissue resident CD8+ T subsets. The NKG2A+CD8+ T cells showed exhausted phenotypes characterized by co-expression of multiple immune inhibitory molecules (PD1, LAG3, TIM3, and TOX) and decreased degranulation capability demonstrated by reduced expression of perforin, granzyme B, and CD107. Importantly, the exhausted NKG2A+CD8+ T-cell subset was associated with disease severity and was significantly increased in ectopic uterine tissues of human patients and mice models with adenomyosis. The expression of NKG2A on CD8+ T cells was markedly upregulated by exogenous rhIL-15 but not rhTGF-β treatment. Additionally, we also found increased co-expression of IL-15 and the NKG2A ligand HLA-E on the glandular epithelial cells, where the NKG2A+CD8+ T cells were closely distributed around the gland, in ectopic adenomyotic microenvironment of patients and mice models with adenomyosis.

Limitations, reasons for caution
The control uterine samples were collected from patients with uterine myoma. Although they were pathologically confirmed as normal, the potential effects are unknown and cannot be excluded. Further studies in larger independent populations and exploration on the functional significance of CD8+ T-cell exhaustion in adenomyosis pathogenesis is warranted.

Wider implications of the findings
Our study reveals a previously unrecognized role for CD8+ T-cell exhaustion in the pathogenesis of adenomyosis and suggests that therapeutic interventions targeting and reinvigorating exhausted CD8+ T cells by NKG2A blockade may be beneficial for patients with adenomyosis.

Trial registration number
not applicable