Hyaluronic acid in dermatomyositis and polymyositis: relationship with disease and cutaneous lesions

BACKGROUND: There are scarce studies in the literature about hyaluronic acid in systemic autoimmune myopathies. OBJECTIVES: To analyze the serum level of hyaluronic acid in patients with dermatomyositis and polymyositis. METHODS: Cross-sectional study, single-center, that evaluated hyaluronic acid in 18 dermatomyositis and 15 polymyositis (Bohan and Peter criteria), newly diagnosed, with clinical and laboratory activity, with no previous drug treatment. The patients were also age-, gender- and ethnicity-matched to 36 healthy individuals. The hyaluronic acid was analyzed by ELISA/EIA kit anti-hyaluronic acid. RESULTS: There was a higher serum level of hyaluronic acid in patients with autoimmune myopathies, in relation to control group (P<0.05). Moreover, the serum level of this glycosaminoglycan was higher in dermatomyositis, when compared to polymyositis. Both groups were comparable with regard to demographic, clinical and laboratory data, except for the presence of skin lesions in the first group. STUDY LIMITATIONS. The presence of hyaluronic acid in cutaneous lesions, particularly of patients with dermatomyositis, was not analyzed neither quantified. In addition, due to disease rarity and the establishment of strict inclusion and exclusion criteria, there was a small sample in the present study. CONCLUSIONS: As an example of others systemic autoimmune diseases, it is possible that the hyaluronic acid is involved in the pathogenesis of autoimmune myopathies, and particularly when associated with cutaneous lesions.