By using 2D-immunoblotting techniques, we will evidence IgG antibodies to fibroblasts, EC, vascular smooth muscle cells (SMC) in multiple groups of patients and we will characterize target antigens of these autoantibodies. We will also assess the production of ROS: nitric oxide (NO), hydrogen peroxide (H2O2) and the effect of the whole serum (and the IgG particularly) on in VITRO proliferation of EC, fibroblasts and vascular SMC. For sera that will induce the production of ROS, we will study the effect of different vasodilatator (prostacycline, endothelin receptor antagonist, type 5 phosphodiesterase inhibitors) and anti-oxidant therapies.