It is a study of basic research with mechanistically objectives and including clinical biological samples.

Systemic sclerosis (SSc) is a rare and severe disease characterised by a fibrotic process and an incompletely elucidate physiopathology. Several shared featured have been identified between SSc and another autoimmune disease, the systemic lupus erythematous (SLE) as an interferon-alpha signature, the role of platelets and the polymorphism of OX40 ligand (OX40L). In SLE, OX40L has been shown highly linked to the active form of the disease, was increased by the CD40L of platelets and induced the CD8 cytotoxicity while inhibiting the suppressive functions of regulator T lymphocytes. The third main factor of the SSc physiopathology apart from autoimmunity and fibrosis is the vasculopathy with an important role of endothelial cells (EC). They turned out to be half-professional antigen presenting cells and can modulate the adaptive immunity.

Inclusion Criteria:

• Age from 18 to 75.
• SSc diagnosed according to the American College of Rheumatology (ACR) criteria.
• With skin manifestations since less than 10 years.
• Localised sclerosis (LSc) diagnosed, morphea type.

Exclusion Criteria:

• Age inferior to 18 or upper than 75.
• Skin manifestations since more than 10 years.
• Haemostasis diseases (independent from treatments).
• Stem cell transplant.
• Immunosuppressive treatments in the last 6 months.
• Associate autoimmune disease.