Microparticles: Bridging the Gap between Autoimmunity and Thrombosis

Microparticles (MPs) are irregularly shaped small vesicles of heterogeneous size released from the plasma membrane in a tightly controlled process, after different stimuli. MPs have been associated with proinflammatory effects and also with autoimmune processes, being a source of autoantigenic nuclear material, which can form immune complexes. In addition, recent reports have linked a large number of autoimmune disorders to an increased risk of thrombosis, and MPs seem to promote the potential for thrombotic events. A growing mass of evidence supports the idea that MPs could contribute to the generation of an inflammation-induced hypercoagulability state, having a relevant role in the pathogenesis of the thrombotic phenomena associated to autoimmune disease, such as systemic lupus erythematosus, antiphospholipid antibody syndrome, and systemic vasculitis. In this review, we focus on the procoagulant properties of circulating MPs and analyze their contribution to the pathogenesis of autoimmune diseases.