Umbilical cord stem cells tested for rare lung condition

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age\> 18 years and \<65 years. * Established diagnosis of systemic sclerosis according to the criteria of the American College of Rheumatology * SSc of poor prognosis, involving life-threatening severe visceral involvement (cardiac or pulmonary hypertension ), lack of response to conventional immunosuppressive therapy used in severe forms of the disease according to the European recommendations of EUSTAR and EBMT, relying on high doses of IV cyclophosphamide (either in monthly bolus for at least six months); or SSc with life-threatening pulmonary hypertension. Patients may or may not have pulmonary fibrosis. * Signed informed consent. * Presence of a consenting MSC donor * Affiliation to social security. Exclusion Criteria: * Pregnancy or absence of appropriate contraception throughout the study. * Pulmonary artery systolic pressure (PASP) \>75mmHg (on echocardiography or after right heart catheterization); \- Theorical DLCO \<30% * Calculated creatinine clearance \<30 ml/mn/m2 * Clinical sign of a congestive heart failure refractory ; * Left ventricular ejection fraction \<35% at myocardial scintigraphy or echocardiography; * Chronic atrial fibrillation requiring oral anticoagulant therapy; * Uncontrolled ventricular arrhythmia; * Pericardial effusion with hemodynamic compromise assessed by echocardiography. * 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