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.