[Expression of B7-H3 costimulatory molecule in peripheral blood of myasthenia gravis patients].

AIM: To reveal the clinical significance of B7-H3 costimulatory molecule in myasthenia gravis(MG) patients by analyzing membranous B7-H3(mB7-H3) and soluble B7-H3(sB7-H3) expressions.METHODS: We collected peripheral blood samples of 35 MG patients and 44 health controls(HC) and detected the expression of mB7-H3 on peripheral blood mononuclear cells(PBMCs) using flow cytometry.ELISA was performed to analyze the levels of sB7-H3 in plasma samples from MG patients and HC.RESULTS: There was no significant difference in the expressions of mB7-H3 on T lymphocytes,monocytes or B cells between MG patients and HC.However,the level of sB7-H3 from MG patients was(2.166±0.958) ng/mL,significantly lower than that from HC(3.379±0.768) ng/mL.The level of sB7-H3 in general MG(GMG) patients(1.664±0.699) ng/mL was lower than that in ocular MG(OMG) patients(2.396±0.985) ng/mL.In MG patients complicated with abnormal thymus,the level of sB7-H3 was(1.593±0.441) ng/mL,also lower than that in MG patients with normal thymus(2.364±1.014) ng/mL.In addition,a significant negative correlation was found between the levels of sB7-H3 and QMGS in MG patients(r=-0.4189,P=0.012),but sB7-H3 was not associated with mB7-H3 in MG patients.CONCLUSION: In MG patients,down-regulation of sB7-H3 is finely correlated to the severity of the disease.Its different expression levels in various types of MG patients indicate that this costimulatory molecule may be involved in the immunopathogenesis of MG.