Disease-specific signature of serum miR-20b and its targets IL-8 and IL-25, in myasthenia gravis patients.

Myasthenia gravis (MG) is an autoimmune disorder characterized by antibodies directed against components of the neuromuscular junction. Currently, the diagnosis and therapeutic evaluation rely on the serum acetylcholine receptor (AchR) antibody titer, which is not reliable for monitoring. The disruption of the menus had been implicated in many immunological disorders, including MG. A quantitative PCR was used to evaluate the miR-20b level. ELISA was used to determine the levels of IL-8 and IL-25 in serum. Quantitative MG scores (QMGS) were used to examine the clinical manifestations. Here, we report that miR-20b, an immune- and cancer-related miRNA, is decreased in the serum of MG patients and correlates negatively with QMGSs in the pretreatment stage. Furthermore, after treatment with prednisone acetate, levels of miR-20b recover but remain negatively correlated with the QMGS. We also identified that IL-8 and IL-25 are targets of miR-20b via the luciferase reporter system. Both of these are increased in MG and correlate negatively with miR-20b. Furthermore, IL-8 and IL-25 levels are decreased following treatment with prednisone acetate. Our data suggest that miR-20b might be a potential biomarker for MG.