Auto-immunity and Pulmonary Arterial Hypertension

Two hundred and fifty patients with PAH will be included: 65 patients with idiopathic PAH (iPAH), 20 with PAH associated with HIV infection, 20 with porto-pulmonary hypertension, 20 with PAH secondary to congenital heart disorders, 40 with SSc, 20 with SLE, 20 with MCTD and 10 with a PAH associated with a Sjögren's syndrome. Two hundred patients without PAH will also be included: 80 patients with SSc and 20 in each of the following groups: HIV infection, porto-pulmonary hypertension, SLE, congenital heart disorders, MCTD and with Sjögren's syndrome. Twenty patients with proximal chronic thromboembolic pulmonary hypertension (CTPH) will also be included in a control arm of the study. Two hundred and fifty healthy blood donors age and sex-matched with patients with PAH, will be included as controls. 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. Expected results We will characterize target antigens of autoantibodies of patients with non-idiopathic and non SSc-associated PAH. We will compare these target to those previously identified in idiopathic or SSc-associated PAH. We will then, distinguish subpopulations of PAH patients whose serum or purified IgG (possibly specific for a given antigen) are able to induce ROS production or cell proliferation. For the population of ROS-producer patients, we will correlate the clinical response to vasodilatator therapy to results of in VITRO inhibition experiments with vasodilatators and anti-oxidant molecules. Perspectives The characterization of target antigens of EC, fibroblasts and vascular SMC specifically