The Changes And Significance Of B Cell Subsets In Peripheral Blood In Patients With Primary Focal Segmental Glomerulosclerosis

Objective: Humoral immunity is involved in the occurrence and development of autoimmune disease,and B cells are the main cells that play an important role of humoral immunity.The purpose of this study was to detect the percentages and functional changes of each subgroup of B cells in patients with primary focal segmental glomerulosclerosis（FSGS）,as well as the potential correlation with clinical indicators,and to explore whether B cells are participated in the pathogenesis of FSGS.Methods: 16 patients with incipient FSGS and 23 Healthy control subjects（HC）were enrolled in this study.Flow cytometry was conducted to analyze the proportions of different subsets of B cells and plasmablasts in peripheral blood mononuclear cells.The level of serum immunoglobulin（Ig）G was determined using Cytometric Bead Array（CBA）.The estimated glomerular filtration rate（e GFR）and 24-h urinary protein were performed with an automatic biochemical analyzer.The relationships among parameters were calculated using Spearman’s rank correlation test.Results: 1.In comparison to HC,the frequencies of CD27+IgD-class-switched memory B cells（P=0.0002）and CD27+IgD-IgG+ class-switched memory B cells（P<0.0001）was markedly increased,and the percentages of CD19+B cells and CD27+IgD-IgM+ class-switched memory B cells were not significantly different between the two groups.2.The proportions of CD38+ plasmablasts,CD27 hi CD38hi plasmablasts,CD138+ plasma cells（P<0.0001）were significantly higher than that those in healthy subjects,IgG+CD38+ plasmablasts（P<0.0001）was significantly lower than that in healthy controls,however,there was no significant difference in the percentage of IgM+CD38+ plasmablasts between the two groups.3.In FSGS patients,the levels of Serum IgG and e GFR were decreased and 24-hour urinary protein were markably elevated（P<0.05）.4.In FSGS patients,the proportion of CD27+IgD-IgG+ class-switched memory B cells was positively correlated with CD27 hi CD38hi plasmablasts and CD138+ plasma cells,and negatively correlated with IgG+CD38+ plasmablasts.5.In FSGS patients,e GFR and Serum IgG concentrations were negatively correlated with the frequencies of CD27+IgD-IgG+ class-switched memory B cells and CD27 hi CD38hi plasmablasts;while serum IgG concentration was positively correlated with the proportion IgG+CD38+ plasmablasts;24 h urinary protein level was positively correlated with the percentage CD27+IgD-IgG+ class-switched memory B cells,and negatively correlated with IgG+CD38+ plasmablasts.Conclusion: 1.Abnormal frequency of CD27+IgD-IgG+ class-switched memory B cells and plasma cells may be responsible for the pathogenesis of FSGS.2.The potential association between CD27+IgD-IgG+ class-switched memory B cells and clinical indicators suggests that CD27+IgD-IgG+ class-switched memory B cells may be closely related to the severity of the disease.3.The abnormal proportions of B cell subsets in FSGS patients which indicate that humoral immunity may be involved in the pathogenesis of FSGS.