The present study is a part of a project previously approved by the local ethics committee (Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - HC/FMUSP - CAPPesq).1. DermatomyositisDermatomyositis (DM) is a rare disease characterized by chronic, systemic, idiopathic, autoimmune inflammatory myopathy, which is associated by high morbidity and functional disability. Moreover, DM is characterized by classical skin lesions (heliotrope and Gottron's papules).2. Hyaluronic acidHyaluronic acid (HA) is a glycosaminoglycan component of the extracellular connective tissue matrix. HA is present in various tissues, such as synovial fluid, ocular humor vitreous, umbilical cord, connective tissue and cartilage. There is also evidence that HA plays a role in the immune response regulation by stimulating the expression of inflammatory genes in various immune cells at the site of injury. HA acts by regulating the inflammatory response through cell recruitment, cytokine release and cell migration. Furthermore, HA stimulates the release of inflammatory factors and cytokines by fibroblasts, contributing to the inflammatory response.3. HA and systemic autoimmune diseasesIt has been reported elevated serum HA levels in some systemic autoimmune diseases, such as rheumatoid arthritis, systemic sclerosis and systemic lupus erythematosus. Notwithstanding, the mechanism responsible for this increasing of serum HA levels is still unknown. Therefore, it is plausible that it is related to the autoimmune mechanism, since the inflammatory activity in these autoimmune diseases is high, and AH has an important role in inflammatory processes.The HA is scarcely studied in DM. Kubo et al. reported two cases with a positive correlation between serum HA and DM activity. These same authors studied a series of 40 patients with DM with higher serum HA and compared them to patients with systemic lupus erythematosus, rheumatoid arthritis and systemic sclerosis. However, HA serum levels did not correlate with disease activity (DM).Hence, the present study aims to determine the serum levels of HA in a large series of patients with DM, correlating it with clinical, laboratory and activity of DM.
News published in Agência FAPESP Newsletter about the scholarship: