CTLA4 and systemic sclerosis: Since human fibrocytes seem to have an antigen-presenting capability, and would appear to be an important source of fibroblasts/myofibroblasts in the physiological and pathological tissue remodeling that characterizes SSc, the aim of this study was to isolate and culture human circulating fibrocytes and skin fibroblasts from the same SSc patients as well as from healthy subjects (HSs) to investigate the possible effects exerted in vitro by CTLA4-Ig treatment.