Figure 1. Percentage of peripheral blood T cells expressing lymphocyte function antigen-1 (LFA-1) (A), very late antigen-4 (VLA-4) (B) and L-selectin (C) in healthy donors (HD), patients with systemic sclerosis (SSc) without pulmonary arterial hypertension and patients with SSc with pulmonary arterial hypertension (SSc-PAH) at baseline (t 0), after 6 months (t 6) and 12 months (t 12) of bosentan therapy. Values are mean (SD).