*Review* **Role of Microparticles in the Pathogenesis of Inflammatory Joint Diseases**

**Magdalena Krajewska-Włodarczyk 1,2,\*, Agnieszka Owczarczyk-Saczonek 3, Zbigniew Zuber ˙ 4, Maja Wojtkiewicz <sup>5</sup> and Joanna Wojtkiewicz <sup>6</sup>**


Received: 4 September 2019; Accepted: 30 October 2019; Published: 1 November 2019

**Abstract:** Rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA) make up a group of chronic immune-mediated inflammatory diseases (IMIDs). The course of these diseases involves chronic inflammation of joints and enthesopathies, which can result in joint damage and disability. Microparticles (MPs) are a group of small spherical membranous vesicles. The structure and cellular origin of MPs, mechanisms that stimulate their secretion and the place of their production, determine their biological properties, which could become manifest in the pathogenesis of immune-mediated inflammatory diseases. Microparticles can stimulate synovitis with proinflammatory cytokines and chemokines. MPs may also contribute to the pathogenesis of rheumatic diseases by the formation of immune complexes and complement activation, pro-coagulation activity, activation of vascular endothelium cells, and stimulation of metalloproteinase production. It seems that in the future, microparticles can become a modern marker of disease activity, a response to treatment, and, possibly, they can be used in the prognosis of the course of arthritis. The knowledge of the complexity of MPs biology remains incomplete and it requires further comprehensive studies to explain how they affect the development of rheumatic diseases. This review focuses on the immunopathogenic and therapeutic role of MPs in chronic immune-mediated inflammatory joint diseases.

**Keywords:** microparticles; joint inflammatory diseases
