Inclusion Criteria:
1. Patients with SSc, aged 18 years or older, and:
2. Subjects must meet the ACR/EULAR classification criteria for SSc (2013).
3. Early dcSSc (within 5 years of first non-Raynaud's phenomenon symptom) or any other dcSSc patients who have at least one of the signs of disease activity: mRSS of 15 or more, presence of tendon friction rubs, elevated inflammatory markers thought to be due to active dcSSc and not related to other issues such as infection or ILD with FVC% predicted \<80% or HRCT showing ILD thought to be from SSc.
4. Able to give informed consent.
Exclusion Criteria:
1. Poor pulmonary function (FVC\<40% and/or DLCO\<30%).
2. Class IV PAH or PH.
3. Clinically significant cardiac disease.
4. Significant concurrent, uncontrolled medical condition including, but not limited to, renal, cardiac, hepatic, pancreatic, hematological, gastrointestinal, endocrine, pulmonary, neurological, cerebral or psychiatric disease; and cancer (i.e. co-existing melanoma, basal cell, or squamous cell skin carcinoma).
5. Chronic or ongoing active infectious disease requiring systemic treatment, including active tuberculosis (TB) infection.
6. Seropositivity for human immunodeficiency virus (HIV) at study entry.
7. Active viral infection with viral replication of hepatitis B or C virus at study entry.
8. Thrombophilia.
9. Contraindications to heparin including history of heparin-induced thrombocytopenia (HIT) or heparin-induced thrombocytopenia and thrombosis (HITTS), history of thrombocytopenia with pentosan polysulfate, known hypersensitivity to heparin or pork products.
10. Low Platelet count (less than 100,000 per mm3).
11. Aphakia (absence or loss of the eye's lens and has not been replaced with an artificial lens), because of the significantly increased risk of retinal damage due to the absence of lenses.
12. Severe anemia (hemoglobin \<70g/L).
13. High white blood cell count (greater than 25000 mm3).
14. A history of surgical spleen removal.
15. A history of a light sensitive disease state, i.e. lupus erythematosus, porphyria cutanea tarda, erythropoietic protoporphyria, variegate porphyria, xeroderma pigmentosum and albinism.
16. Previous idiosyncratic reactions to psoralen compounds.
17. Patients who are using photosensitizing drugs such as anthralin, coal tar or coal tar derivatives, griseofulvin, phenothiazines, nalidixic acid, halogenated salicylanilides (bacteriostatic soaps), sulfonamides, tetracyclines, thiazides, and certain organic staining dyes such as methylene blue, toluidine blue, rose bengal and methyl orange.
18. Treatment with more than 2 immunosuppressants (including mofetil mycophenolate, methotrexate, cyclophosphamide, biologics) at study entry.
19. Pregnancy, breast feeding or child bearing potential without practicing highly effective contraception (and partners for men in the study).
20. Patients known or suspected of not being able to comply with a study protocol (e.g. due to alcoholism, drug dependency or psychological disorder).
21. Participation in another clinical trial within six weeks before randomization in this study.
22. Previous use of Extracorporeal photopheresis.
