Low levels of alpha-synuclein in peripheral tissues are related to clinical relapse in relapsing-remitting multiple sclerosis: a pilot cross-sectional study

摘要

The protein alpha-synuclein (alpha-Syn) has been linked to neuroinflammatory conditions. We investigated whether the presence of alpha-Syn in peripheral tissues is a surrogate of brain inflammatory status in a small group of relapsing-remitting multiple sclerosis (RAMS) patients in a pilot cross-sectional study. Skin biopsies and peripheral blood were sampled from 34 healthy controls and 23 MS patients for measurement of alpha-Syn levels. Within the RAMS group 15 patients were in remission, and 8 patients were in the relapsing phase. The protein alpha-Syn was evaluated by means of immunohistochemistry and flow cytometry in skin and nucleated blood cells, respectively. In the skin, alpha-Syn levels were lower in relapsing MS than in the other groups, both in positive area (p = .021) and staining intensity (p = .004). In blood, the percentage of alpha-Syn-positive lymphocytes and monocytes were not statistically different between study groups. Moreover, the use of systemic steroids did not affect alpha-Syn positivity in MS-relapse patients. Finally, epidermic Langerhans cells did not stain positively for alpha-Syn. Overall, the levels of alpha-Syn positivity were lower in inflammatory relapse of RRMS patients when measured in peripheral tissues. We discuss the role of alpha-Syn levels in inflammation according to the obtained results.