PDGFRB and systemic sclerosis: Of the 386 cases diagnosed with IIP, 48 were SSc-Ab positive, including anti-PDGFR antibody in zero, anti-Th/To antibody in 10, anti-NOR90 antibody in 12, anti-fibrillarin antibody in five, anti-RP155 antibody in 14, anti-RP11 antibody in three, anti-CENP A antibody in seven, anti-CENP B antibody in 10, and anti-Scl-70 antibody in six.