Evaluation of Cell Membrane Expression of Annexin A2 on Monocytes by Flow Cytometry in Primary Antiphospholipid Syndrome (MONOCYTAN)

November 17, 2025 updated by: Centre Hospitalier Universitaire, Amiens
Annexin A2 (ANXA2), an endothelial cell receptor for plasminogen and tissue plasminogen activator, plays a pivotal role in regulation of fibrinolysis in vitro and in vivo and has been identified as a new autoantigen in antiphospholipid syndrome (APS). ANXA2 can exist as a monomer or a heterotetrameric complex with S100A10 protein. The aim of this study was to evaluate the cell membrane expression of ANXA2 on circulating monocytes in APS by flow cytometry. Several pathogenic mechanisms are involved in APS such as activation of endothelial cells, platelets and monocytes, inhibition of the natural anticoagulant protein C/protein S pathway, activation of the complement system and also impairment of fibrinolysis. Annexin A2 which hits binding partner S100A10, ANXA2 forms a cell surface complex that regulates generation of plasmin. ANXA2 is involved in the pathogenesis of APS-associated through several possible mechanisms. Human peripheral blood monocytes represent the major circulating ANXA2-expressing cell and ANXA2-mediated assembly of plasminogen and tissue activator of plasminogen (tPA) on monocyte/macrophages contributes to plasmin generation. Thus the investigators could suppose that decrease of cell membrane expression of ANXA2 on circulating monocytes represent a new pathogenic mechanism in APS.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

60

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

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

Yes

Description

Inclusion Criteria:

  • APS patients who fulfilled the revised criteria for APS

Exclusion Criteria:

  • Patients less than 18 years old
  • Solid and hematological malignancies
  • Other autoimmune diseases
  • Cirrhosis

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: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: case
APS patients
Biological: blood withdrawal
blood withdrawal
Active Comparator: control
healthy individuals
Biological: blood withdrawal
blood withdrawal

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Cell membrane expression rate of ANXA2 on circulating monocytes in APS
Time Frame: 1 hour
1 hour

Secondary Outcome Measures

Outcome Measure
Time Frame
Cellular expression of ANXA2 and S100A10 in APS patients
Time Frame: 1 hour
1 hour
cell membrane expression of ANXA2 and S100A10 in APS patients
Time Frame: 1 hour
1 hour

Collaborators and Investigators

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

Sponsor

Centre Hospitalier Universitaire, Amiens

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 (Actual)

February 5, 2025

Primary Completion (Estimated)

March 1, 2026

Study Completion (Estimated)

March 1, 2026

Study Registration Dates

First Submitted

April 9, 2024

First Submitted That Met QC Criteria

April 16, 2024

First Posted (Actual)

April 18, 2024

Study Record Updates

Last Update Posted (Actual)

November 19, 2025

Last Update Submitted That Met QC Criteria

November 17, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PI2019_843_0010

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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