- Patient with systemic sclerosis fulfilling the ACR -American college of rheumatology - (Masi et al. 1980) and/or Leroy and Medsger (LeRoy and Medsger 2001) diagnostics criteria with worsening ILD (interstitial lung disease) identified on a high resolution chest CT scan and by worsening of forced vital capacity (FVC) and/or total lung capacity (TLC) ≥10% and/or worsening of DLCO ≥ 15% as compared to values obtained within the 3 to 18 months preceding inclusion (for DLCO, in the absence of pulmonary arterial hypertension upon echocardiography)