Microparticles's Role in the Pathophysiology of Systemic Lupus Erythematosus and Systemic Sclerosis

Systemic lupus erythematosus (SLE) and systemic scleroderma (SSc) are two rare and potentially life-threatening auto-immune systemic diseases. There is an urgent need to describe prognostic factors and to discover new therapeutic pathways. Microparticles (MPs) are small extracellular vesicles formed from activated cells including endothelial cells and platelets. Preliminary data from our lab indicate that these MPs might play a key role in SLE and SSc physiopathology. In fact, MPs from patients with SLE aggregates with T regulator lymphocytes (LTregs) and decrease their activity, thereby promoting auto-immunity. Some works also indicate that MPs might cargo DNA to the immune system, also promoting auto-immunity. The investigators hypothesized that MPs levels might be a prognostic factor in SLE and SSc and that studying the molecular mechanisms involved could provide new therapeutic targets.

Our study will recruit 100 patients with SLE or SSc followed in Bordeaux University Hospital. Among classical disease activity information, blood and urine samples will be collected at each visit to study circulating microparticles. Fundamental research will be realized on patients' sample to study molecular mechanisms involved.

Clinical and biological disease activity, treatment and outcomes will be studied in correlation with MPs to describe their potential prognostic role. Patients will be followed at regular intervals as their usual follow-up would request. No extra visit will be needed and blood samples will be drawn at the same times as those drawn for clinical purposes.

Inclusion criteria

• diagnosis of systemic lupus erythematosus or systemic sclerosis;
• age ≥ 18 years;
• being affiliated to health insurance, willing to participate and to sign informed consent.

Exclusion criteria

• pregnant or breastfeeding women;
• patient concerned by articles L 1121-5 to L 1121-8 (persons deprived of their liberty by a judicial or administrative decision, minors, persons of legal age who are the object of a legal protection measure or unable to express their consent)