Figure 5.

Phosphorylated platelet-derived growth factor receptor expression in the control systemic sclerosis patients. Collagen accumulation does not improve in a control patient following cyclophosphamide treatment (B) compared with baseline (A). Immunohistochemical staining for phosphorylated platelet-derived growth factor receptor (PDGFR)α and PDGFRβ in the same patient prior to ((C) and (E), respectively) and following ((D) and (F), respectively) rituximab (RTX) treatment, where no change in phospho-PDGFR staining can be seen (streptavidin peroxidase ×100). Red arrow in the boxed area points to a spindle-like cell (among others) expressing phosphorylated PDGFRα and PDGFRβ.