The aim of the study is to assess the effectiveness of various post-transplant treatment management approaches on clinical and immune biological responses after Autologous Hematopoietic Stem Cell transplantation (AHSCT) for Systemic Sclerosis (SSc) as currently performed by the different treatment protocols used in routine clinical practice across Europe in various EBMT centres

NISSc-2 is a prospective observational study specifically designed to assess the effectiveness of various post-transplant treatment management approaches on clinical and immune biological responses after Autologous Hematopoietic Stem Cell transplantation (AHSCT) for Systemic Sclerosis (SSc) as currently performed by the different treatment protocols used in routine clinical practice across Europe in various EBMT centres through the careful recording and analysis of routinely collected clinical and immune biological data, and specific data regarding post-transplant use of SSc active treatments, including:

• Steroids,
• SSc active treatments after AHSCT such as mycophenolate mofetil (MMF), azathioprine, cyclophosphamide (oral or IV), methotrexate, polyclonal antibodies (such as ATG) or monoclonal antibodies (rituximab, belimumab or any others) as well as their respective dosage and duration of each treatment. These post-transplant treatments can be administered for various reasons, which can be specified by local investigators, such as per local protocol decision for maintenance therapy, or for disease progression with or without prior clinical response, during routine clinical follow-up. Patients who do not receive any post-transplant therapy will also be observed.

Different protocols are used in the different centres, but it is not yet clear, which approach will be the most efficient and the safest. The role of stem cell purification with CD34-selection also needs to be determined prospectively.

In addition, the EBMT Autoimmune Diseases and Immunobiology Working Parties developed and implemented guidelines for 'good laboratory practice' in relation to procurement, processing, storage and analysis of biological specimens for immune reconstitution studies in AD patients before, during and after AHSCT [16]. To follow post-transplant immune reconstitution according to ADWP GCP, results of routine analyses performed by centres under standardized conditions on available biological samples will be investigated in correlation to clinical outcome parameters. Every centre will follow its own local protocol for AHSCT, which usually refers to the recent update of the EBMT guidelines for AHSCT in autoimmune disease.

We therefore specifically designed NISCC-II to prospectively capture various post-ASHCT management protocols and their effect on the observed clinical response after AHSCT.

Inclusion Criteria:

1. - Autologous HSCT
2. - Age above 18 years at time of transplant.
3. -. Established diagnosis of progressive SSc according to 2013 ACR/EULAR classification criteria

Exclusion Criteria:

1. Pregnancy or inadequate contraception

2. Severe concomitant disease

3. Reduced lung, cardiac or renal function

   a. .Reduced lung function with FVC < 50% or DLCO < 30% (of predicted values) b; .Pulmonary arterial hypertension with baseline (resting) PASP > 40 mmHg or mPAP > 25 mmHg or a PASP > 45 mmHg or mPAP > 30 mmHg after fluid challenge or Pulmonary vascular resistance > 3 Wood units on RHC c. Severe heart failure with Ejection Fraction < 45% by cardiac echocardiography d. D-sign of septal bounce on cardiac MRI e. Unrevascularized severe coronary artery disease f. Untreated severe arrhythmia g. Cardiac tamponade h. Constrictive pericarditis i. Kidney insufficiency: creatinine clearance <30ml/min Previously damaged bone marrow

   1. Leukopenia < 2.0 x 109/L (total white cell count)
   2. Thrombocytopenia < 100 x 109/L

4. Uncontrolled severe or chronic infection (Hepatitis B/C, HIV, Salmonella carrier, syphilis, tuberculosis)

5. Severe concomitant psychiatric illness (depression, psychosis)

6. Concurrent neoplasms or myelodysplasia in the past 5 years

7. Smoking (current)

All consecutive patients treated with AHSCT for progressive systemic sclerosis in participating centres