 3. Molecular Analysis of T Cell Immune Recovery for the SCOT TrialOriginally listed separately as DAIT SCSSc-01-03, NCT00872508. The purpose of this study is 1 to describe the condition of peripheral T cell reactivity and repertoire diversity in SSc patients and evaluate evidence for potential defects prior to randomization, 2 to gain a better understanding of the impact of cyclophosphamide Cytoxan and high-dose immunosuppressive therapy with autologous stem cell transplantation on thymopoiesis, and 3 to describe the kinetics and breadth of T cell immune recovery in SSc patients treated with these interventions. 