PLXNB1 and systemic sclerosis: In spite of the scarcity of microvessels in the lesional skin biopsies of SSc patients, all tissue samples from both normal (six biopsies) and SSc (six biopsies) subjects showed the presence of endothelial cells exhibiting immunoreactivity for KLK9, KLK11, KLK12, DSG2, plexin B1, IL8, PLAU, pent(r)axin 3, and connective tissue growth factor.