PDGFRA and systemic sclerosis: On the contrary, we found no change in the expression of phosphorylated PDGFRα and PDGFRβ at 6 months compared with baseline in the control SSc patients (mean ± SEM at baseline vs. 6 months, respectively: phospho-PDGFRα, 33.27 ± 7.21 vs. 33.63 ± 3.58; and phospho-PDGFRβ, 28.90 ± 6.92 vs. 31.07 ± 4.17; P = not significant in both cases).