In fact, it is estimated that up to 30–40% of patients with PAH from various etiologies have evidence of elevated plasma levels of circulating autoantibodies, pro-inflammatory cytokines such as interleukin 1 (IL-1) and interleukin 6 (IL-6) and chemokines such as fractalkine and MCP-1 [12]. This evidence concerns the gene CX3CL1 and pulmonary arterial hypertension.