Inclusion Criteria:  SSc according to the 2013 ACR/EULAR 2013 criteria (or the 2001 Leroy's criteria for early SSc)  Patients with others connective tissue disease:  Systemic erythematosus lupus (SLE) according to the 2019 ACR/EULAR criteria Primary Sjögren syndrome (pSS) according to the 2016 ACR/EULAR criteria Rheumatoid arthritis according to the 2010 ACR/EULAR criteria Idiopathic inflammatory myopathy (IIM) according to the 2017 ACR/EULAR criteria Healthy subjects from general population without known autoimmune disease or connective tissue disease ≥18 years-old  Exclusion Criteria:  Overlap syndrome (including secondary Sjögren syndrome) Weight <55 kgs Known primary cell immunodeficiency Immunosuppressive drug in the past 3 months (hydroxychloroquine and glucocorticoids ≤7.5mg/d allowed) Biotherapy in the past 6 months Past of autologous or allogenic hematopoietic stem cell transplantation Solid neoplasia or malignant hemopathy in remission for less than 12 months an Chemotherapy and/or immune checkpoint inhibitors in the last 12 months Systemic retinoids Active infection and/or antibiotics in the last 2 weeks Known active chronic infection among HIV, HTLV, viral hepatitis, syphilis Vaccination in the last 4 weeks Subject refusing genetic analysis for the present study Pregnancy or breastfeeding