Expression of costimulatory molecule inducible costimulator and coinhibitory molecule programmed death-1 in patients with myasthenia gravis / 中华神经科杂志

ABSTRACT

Objective To explore the immunopathological mechanism for the imbalance between the positive signal mediated by inducible costimulator (ICOS) and the negative signal mediated by programmed death-1 (PD-1) in patients with myasthenia gravis (MG).Methods Eighty-two patients with MG,56 healthy controls (HC) and 20 non-MG (NMG) patients,collected in the First Affiliated Hospital of Suzhou University from February 2014 to December 2016,were chosen to participate in the study.The expression of ICOS and PD-1 on peripheral blood mononuclear cells was detected by immuno-fluorescence staining and flow cytometry.The levels of soluble programmed death-1 (sPD-1),soluble programmed death ligand 1 (sPD-L1),IL-4 and other cytokines were detected by enzyme-linked immunosorbent assay.Results (1) Flow cytometry analysis:The co-expression of PD-1,ICOS on CD4 + T cells from MG group (9.64％ (8.82％)) was higher than in HC (1.81％ (2.10％),Z =-7.389,P ＜0.05) and NMG group (2.86％ (1.49％),Z =-4.636,P ＜ 0.05).The expression of ICOS on CD4 + T cells,ICOS ligand (ICOSL) on CD14+ monocytes and CD19+ B cells were increased in MG group comparing with that of the control groups.The proportion of PD-1 + CD4 + T cells (MG group 16.82％ (10.66％),HC 9.34％ (9.18％),Z =-4.345,P＜0.05;NMG group 7.07％ (3.40％),Z=-4.594,P＜0.05) and PD-1 Ligand (PD-L1) + CD14+ monocytes was higher in MG patients.All of these were detected by flow cytometry.(2) ELISA analysis:Serum sPD-1 expression significantly increased in MG group compared with that in the control groups (MG group (1.87 ± 0.64) ng/ml,NMG group (1.49 ± 0.70) ng/ml,t =2.04,P ＜ 0.05;HC (1.05 ± 0.50)ng/ml,t =2.08,P ＜ 0.05),while for serum sPD-L1,there was no significant difference between MG and control groups.(3) Serum cytokines detectionThe expression of IL-4 was increased in MG patients (MG group (61.88 ±5.15) pg/ml,HC (32.03 ±1.84) pg/ml,t=2.50,P＜0.05;NMG group (42.62± 3.31) pg/ml,t =2.34,P ＜0.05),and there was a negative correlation between the expression of sPD-1 and the concentration of IL-4.Conclusions The increased expression of PD-1 + ICOS + CD4 + T cells suggested the subset involved in the pathological progress of MG.sPD-1 might disturb the ligation of PD-1 on T cells and PD-L1 on antigen presenting cells,while the ligation of ICOS and ICOSL passed positive signal,leading to over activity of the subsets and the progression of disease.