NPPB and systemic sclerosis: Interestingly, we did not find any correlation to RHC verified PH, sPAP on ECHO or NT-proBNP in the two SSc cohorts and no CX3CL1/CX3CR1 protein expression on endothelial cells strengthening the assumption that CX3CL1 is associated with SSc-ILD and not pulmonary vascular disease.