The main ailm of this phase I-II study is to evaluate toxicity and efficacy of allogenic mesenchymal stem cell therapy to treat severe systemic sclerosis. In practice this treatment will be given to patients with a rapidly evolutive disease or refractory to cyclophosphamide.

Inclusion Criteria:

• Age> 18 years and <70 years.
• Established diagnosis of systemic sclerosis according to the criteria of the American College of Rheumatology
• SSc of poor prognosis, involving life-threatening with sever visceral impairment (cardiac, pulmonary or renal) AND " a) contraindicating the use of or b) resistant to " immunosuppressive therapy conventionally used in severe forms of the disease according to the European recommendations of EUSTAR (www.eustar.org) and EBMT (www.ebmt.org) which then rely on high doses of iv cyclophosphamide (either in monthly bolus at least six months or by intensification and autograft of Hematopoietic Stem Cells) or SSc with fibrosing lung damage threatening the vital prognosis which excludes a lung transplant.

These forms of severe and serious SSc WITH at least 6 months follow-up after completion of prior immunosuppressive therapy by high doses of iv cyclophosphamide when they were made, combine to varying degrees : rapidly progressive skin lesions with a score of Rodnan> 15 and one or more of the major visceral lesions defined as follows :

1. Respiratory disease :

   DLCO <60% or FVC ≤70% of the theoretical value and the presence of interstitial lung disease (abnormalities on chest radiograph and / or lung HRCT with thin sections). It is necessary to ensure that non-related etiologies to scleroderma were eliminated; example: obstructive lung disease (chronic obstructive pulmonary disease or pulmonary emphysema). If the fibrosing lung disease threatens the vital prognosis, we will ensure of the exclusion of a possible lung transplant.

   And/or

2. Heart disease:

congestive heart failure reversible, ventricular or atrial rhythm disturbances defined as recurrent episodes of atrial fibrillation or atrial flutter, recurrent paroxysmal atrial tachycardia or ventricular tachycardia, atrioventricular block of second or third degree, pericardial effusion with high abundance needing specific treatment of medical type (introduction of steroids) or surgical type (drainage). It is necessary to ensure that non-related etiologies to scleroderma were removed.

• Signed informed consent.
• Presence of a consenting intrafamilial MSC donor
• Affiliation to social security.

Exclusion Criteria:

• Pregnancy or absence of appropriate contraception throughout the study.
• Respiratory Disease:
• systolic Pulmonary arterial pressure (PASP)>55mmHg (on echocardiography or after right heart catheterization);
• DLCO <30% of the theorical ;
• Respiratory failure defined by oxygen arterial pressure at rest (PaO2) <8 kPa (<60 mmHg) and / or a blood pressure of carbon dioxide at rest (PaCO2)> 6.7 kPa (> 50 mmHg) without oxygen therapy.

Renal Disease:

• Calculated creatinine clearance <20 ml/mn/m2
• Sequelae cystopathy post treatment by cyclophosphamide
• Heart disease:
• Clinical sign of a congestive heart failure refractory ;
• Left ventricular ejection fraction <35% at myocardial scintigraphy or echocardiography;
• Pulmonary arterial hypertension confirmed by right catheterization or suspected pulmonary hypertension with systolic PAP at echography > 40 mmHg
• Chronic atrial fibrillation requiring oral anticoagulant therapy;
• Uncontrolled ventricular arrhythmia;
• Pericardial effusion with hemodynamic compromise assessed by echocardiography.
• Hepatic Disease:
• Hepatic impairment defined as a persistent increase in transaminases or bilirubin to 3 times normal.
• Psychiatric disorders, including drug taking and alcohol abuse.
• Active neoplasia or concomitant myelodysplasia, antecedent of neoplasia.
• Bone marrow failure defined by neutropenia <0.5 x 109 / L, thrombocytopenia <50 x 109 / L, anemia <8 g / dL, CD4 lymphopenia <200 x 106 / L.
• Uncontrolled systemic hypertension.
• Uncontrolled acute or chronic infection, HIV1, 2 or HTLV-1, 2seropositivity.
• Chronic hepatitis B or C active.
• Significant exposure to bleomycin, toxic oils, vinyl chloride, trichloroethylene or silica; eosinophilia-myalgia syndrome, eosinophilia fasciitis.
• Risk of poor patient compliance.