Analysis of PBMC from patients with SSc revealed CD169/sialoadhesin (Siglec-1) and other IFN-regulated genes were overexpressed in patients with dcSSc, whereas patients with lcSSc with PAH overexpressed IL-13RA1, intercellular adhesion molecule-1 (ICAM-1), C–C chemokine receptor type 1 protein or gene (CCR1), JAK2, and melanocortin receptor 1 (MCR1) (123, 125, 126). Here, CCR1 is linked to pulmonary arterial hypertension.