MiR-15a contributes abnormal immune response in myasthenia gravis by targeting CXCL10.

MiR-15a is likely to be associated with autoimmunity. Here, we aimed to examine the expression of miR-15 cluster in PBMCs from myasthenia gravis (MG) patients and investigate the potential roles of miR-15a in MG. We found that the expression of all miR-15 cluster was decreased in MG, furthermore, miR-15a levels in ocular MG (oMG) were much lower, while CXCL10 production was increased in MG. We display that CXCL10 was a functional target gene of miR-15a in MG. Increasing miR-15a expression could reduce CXCL10 expression and alleviate the abnormal T cells activation in immune response, while decreasing miR-15a expression could activate immune response abnormally. Moreover, miR-15a expression was significantly decreased after stimulation, and prednisone treatment could upregulate miR-15a expression in steroid-responsive MG patients. Take together, our data suggest that decreased miR-15a expression facilitates proinflammatory cytokines production and contributes to immune response at least in part via regulating CXCL10 expression in MG.

[Congenital myopathy with type 1 fiber predominance in two children].

Non-progressive congenital myopathy is a group of muscle diseases occurring at birth or during teenage years. A number of new reports of congenital myopathy, such as homogeneous bodies myopathy, muscle quality control myopathy and type 1 fiber predominance have recently been reported, but they lack of sufficient quantity and constant clinico-pathologic manifestations. This paper reports two cases of congenital myopathy with type 1 fiber predominance confirmed by muscle biopsy. The clinical manifestations of the two children (a 4.5-year-old girl and an 11-year-old boy) included non-progressive symptoms of muscle weakness, skeletal deformities and other clinical features of congenital myopathy. The physical examinations showed a long face or figure and funnel chest or kyphosis/scoliosis, high palatal arch and wing-like shoulder. Serum levels of creatine kinase were normal but slightly elevated serum lactate dehydrogenase levels were noted in the two children. The skeletal muscle biopsy by ATPase staining showed that type 1 fibers accounted for more than 90% of the total number of muscle fibers. No other abnormal pathological changes, such as central cores, muscle tube and central nuclei, were found in the two children.