Changes of CD28~-T cell subsets and their clinical significance in myasthenia gravis patients

To investigate the clinical significance of CD28-T cell subsets in myasthenia gravis(MG) patients by analyzing the expressions of CD4,CD8 and CD28 on peripheral blood lymphocytes,peripheral blood samples of 46 MG patients and 35 health controls(HC) were collected in our study.CD4,CD8 and CD28 expressed on lymphocytes were detected by flow cytometer.The results showed that there were no significant differences in CD4 and CD8 expressions on T lymphocytes between MG patients and HC.However,a decreased expression of CD28 was observed in MG patients.The percentage of CD4+CD28-T cells in MG patients(13.53%±6.31%) was significantly higher than that in HC(9.24%±4.62%,P=0.001),but a lower percentage of CD8+CD28-T cells was found in MG patients(39.22%±11.91%) than that in HC(48.41%±13.63%,P=0.002).CD4+CD28-T cell subset was enriched in GMG patients and MG patients complicated with abnormal thymus,while OMG patients and patients with normal thymus had an enrichment of CD8+CD28-T cell subset.In addition,both CD4+CD28-(r=0.4113,P=0.0045) and CD8+CD28-(r=-0.3989,P=0.0060) T cell subsets were closely correlated to QMGS in MG patients.A decreased proportion of CD4+CD28-T cells(P=0.018) and an increased percentage of CD8+CD28-T cells(P=0.018) were found in MG patients on methylprednisolone therapy.Our study suggests that in MG patients there is an enrichment of CD4+CD28-subset and a decline of CD8+CD28-T cell subset,which is correlated to the severity of disease and corticosteroids therapy.In various clinical types of MG,significant differences between these two CD28-T cell subsets were observed,which indicated that changes of these two CD28-T cell subsets might be involved in the autoimmunity of MG.