Interaction Between Decidual Cells and NK Cells in Endometriosis (PAINLESS)

June 11, 2026 updated by: Hopital Foch

Interaction Between Decidual Cells and Natural Killer Cells in Endometriosis: A Prospective Pilot Case-Control Study

Endometriosis is a chronic gynecological disease characterized by the presence of endometrial-like tissue outside the uterus and is frequently associated with pelvic pain and infertility. Increasing evidence suggests that immune dysfunction may contribute to the development and persistence of the disease.

The purpose of this prospective case-control study is to compare immune cell characteristics in women with deep endometriosis and women without endometriosis during the secretory phase of the menstrual cycle. Participants will undergo collection of clinical data, blood samples, endometrial samples, and vaginal microbiota samples. For participants undergoing clinically indicated pelvic surgery, additional biological samples may be collected during the procedure. The study aims to improve understanding of the immune mechanisms involved in endometriosis and to identify potential biomarkers associated with the disease.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Endometriosis affects approximately 10-15% of women of reproductive age and represents a major public health concern. Despite its high prevalence, the pathophysiological mechanisms underlying the disease remain incompletely understood. Increasing evidence suggests that alterations in the immune environment of the endometrium may contribute to the establishment and progression of endometriosis. In particular, uterine immune cells may play a role in regulating local inflammation and tissue homeostasis. Characterizing these immune mechanisms may improve understanding of disease development and identify potential biomarkers associated with endometriosis.

PAINLESS is a prospective, single-center, pilot case-control study conducted at Foch Hospital (Suresnes, France). The study will enroll 50 adult women, including 25 participants with confirmed deep endometriosis and 25 control participants without endometriosis.

Biological samples will be collected during the secretory phase of the menstrual cycle (days 16-24). Depending on clinical management, study procedures may include:

  • Collection of demographic and clinical data
  • Assessment of symptoms and quality of life
  • Blood sampling
  • Endometrial sampling
  • Vaginal microbiota sampling
  • Collection of additional biological specimens during clinically indicated pelvic surgery.

Biological samples will be analyzed to characterize immune cell populations, evaluate soluble immune mediators, investigate associations with hormonal and clinical parameters, and explore biological mechanisms involved in endometriosis.The primary objective is to compare the expression of immune-related markers in endometrial and peritoneal samples obtained from women with endometriosis and controls. Secondary objectives include characterization of immune cell phenotypes and functions, evaluation of immune-related soluble factors, investigation of interactions between immune and endometrial cells, assessment of correlations with hormonal and clinical data, exploratory genetic analyses, and creation of a vaginal microbiota biobank. Results from this pilot study are expected to provide preliminary data for future research aimed at improving the understanding, diagnosis, and management of endometriosis.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • France
      • Suresnes, France, 92150
        • Hôpital Foch
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Endometriosis Group
  • Female participant aged 18 years or older.
  • Confirmed diagnosis of deep endometriosis by imaging or surgery.
  • Pelvic pain and/or severe dysmenorrhea (Visual Analog Scale > 4).
  • Premenopausal.
  • No contraceptive or hormonal treatment during the study menstrual cycle.
  • Affiliated with a health insurance system.
  • Able and willing to provide written informed consent.
  • Control Group
  • Female participant aged 18 years or older.
  • No diagnosis of endometriosis.
  • Premenopausal.
  • No contraceptive or hormonal treatment during the study menstrual cycle.
  • No chronic pelvic pain or severe dysmenorrhea (Visual Analog Scale < 4).
  • Affiliated with a health insurance system.
  • Able and willing to provide written informed consent.

Exclusion Criteria:

  • Current infection.
  • Active cancer.
  • Active autoimmune disease.
  • Concomitant hormonal treatment.
  • Pregnancy.
  • Participant under guardianship or legal protection.
  • Participant deprived of liberty.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Endometriosis Group
Adult women with confirmed deep endometriosis undergoing collection of clinical data and biological samples, including blood, endometrial tissue, vaginal microbiota samples, and, when clinically indicated, additional samples collected during pelvic surgery.
Procedure: Biological Sample Collection
Collection of blood samples, endometrial samples, vaginal microbiota samples, and surgical specimens when clinically indicated for immunological and biomarker analyses.
Active Comparator: Control Group
Adult women without endometriosis undergoing collection of clinical data and biological samples, including blood, endometrial tissue, vaginal microbiota samples, and, when clinically indicated, additional samples collected during pelvic surgery.
Procedure: Biological Sample Collection
Collection of blood samples, endometrial samples, vaginal microbiota samples, and surgical specimens when clinically indicated for immunological and biomarker analyses.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
CD39 Expression on Natural Killer Cells in Endometrial and Peritoneal Samples
Time Frame: At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Comparison of CD39 expression on natural killer (NK) cells in endometrial and peritoneal samples collected from women with deep endometriosis and women without endometriosis.
At sample collection during the secretory phase of the menstrual cycle (Days 16-24)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
NK Cell Cytotoxic Function
Time Frame: At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Assessment of NK cell cytotoxic activity through degranulation markers and cytokine production in biological samples.
At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Endometrial and NK Cell Interactions
Time Frame: At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Evaluation of interactions between endometrial cells and NK cells using tissue-based analyses.
At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Ex Vivo Modulation of NK Cell Function
Time Frame: Following sample collection, up to study completion (16 months)
Evaluation of the effects of cytokine stimulation on NK cell function and endometrial cell responses in laboratory assays.
Following sample collection, up to study completion (16 months)
Association Between Hormonal Levels and NK Cell Profile
Time Frame: At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Correlation of estrogen and progesterone levels with NK cell characteristics and immune markers.
At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Association Between Clinical Characteristics and Immune Markers
Time Frame: At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Correlation between clinical features of endometriosis and immunological findings.
At sample collection during the secretory phase of the menstrual cycle (Days 16-24)
Genetic Biomarker Associations
Time Frame: At sample collection and laboratory analysis up to study completion (16 months)
Assessment of associations between genetic markers and immunological findings.
At sample collection and laboratory analysis up to study completion (16 months)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hopital Foch

Investigators

  • Principal Investigator: Marie CARBONNEL, MD, Foch hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

October 1, 2027

Study Completion (Estimated)

October 1, 2027

Study Registration Dates

First Submitted

June 11, 2026

First Submitted That Met QC Criteria

June 11, 2026

First Posted (Actual)

June 17, 2026

Study Record Updates

Last Update Posted (Actual)

June 17, 2026

Last Update Submitted That Met QC Criteria

June 11, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2024_0074

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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