PDGFRB and systemic sclerosis: Although no clear associations have been reported between anti-PDGFR and clinical features in SSc patients, a recent study found that agonistic antibodies prompted the proliferation and migration of human pulmonary vascular smooth muscle cells in vitro; this suggests that anti-PDGFR antibodies may be involved in establishing PAH in SSc, albeit this has not yet been investigated in vivo [25].