Abstract:OBJECTIVE: Myasthenia gravis is an autoimmunity disease and its pathogenesis has not been fully identified. Heat shock protein 90 (HSP90) shows an abnormal expression in other autoimmunity diseases. This study examined the mRNA expression of two isoforms of HSP90 in peripheral blood mononuclear cells (PBMC) and serum cortisol content in children with myasthenia gravis. METHODS: Thirty-six children with myasthenia gravis and 19 healthy children were enrolled. Serum cortisol content was measured by the chemiluminescence assay. The expression of HSP90α and HSP90β mRNA in PBMC was detected by the RT-PCR technique. RESULTS: The mRNA expression of HSP90α (0.7329±0.2120) and HSP90β (0.7193±0.2869) in children with myasthenia gravis was significantly higher than that in healthy controls (0.5574±0.2084 and 0.4892±0.2104 respectively) (P<0.01). Serum cortisol content (285.04±146.39 nmol/L) in children with myasthenia gravis was also higher than that in the healthy controls (196.25±64.52 nmol/L) (P<0.01). CONCLUSIONS: The high mRNA expression of HSP90α and HSP90β in PBMC might be associated with the development of myasthenia gravis. The high serum cortisol level indicates a high stress state or might be correlated to the glucocorticoid receptor abnormality in children with myasthenia gravis.［Chin J Contemp Pediatr, 2009, 11 (6):453-456］
