维生素D通过STAT3-CD23轴抑制屋尘螨过敏患儿B细胞活化及IgE分泌OA

Objective:To investigate the effect of vitamin D on B cell activation and total immunoglobulin E(IgE)secretion in children with house dust mite allergy and the underlying molecular mechanisms.Methods:A total of 126 children with house dust mite allergy(allergy group)and 81 healthy children(control group)were enrolled.Serum levels of 25-hydroxyvitamin D[25-(OH)D],total IgE,dermatophagoides pteronyssinus peptidase 1(Derp1)-specific IgE,and soluble CD23(sCD23)were measured.Pearson correlation analysis was used to assess the relationships between serum 25-(OH)D levels and total IgE,Derp1-specific IgE,sCD23 levels,and the proportion of CD19+CD23+B cells in peripheral blood.The diagnostic value of serum 25-(OH)D for house dust mite allergy was assessed using receiver operating characteristic(ROC)curve analysis.CD19+B cells isolated from allergic children were divided into negative control group(routine culture),positive control group(1 μg/mL lipopolysaccharide),and three treatment groups with 10,50,and 100 nmol/L 1,25-(OH)2D3,respectively;cells were co-cultured for 48 hours.Flow cytometry was used to detect membrane expression of CD23,while Western blotting was assessed levels of signal transducer and activator of transcription 3(STAT3),STAT5,p-STAT3,and p-STAT5.ELISA was employed to measure IgE secretion.Time-course experiments were conducted to observe dynamic changes in STAT3 phosphorylation and IgE secretion at different time points after 100 nmol/L 1,25-(OH)2D3 treatment.CD19+B cells were further divided into four groups:negative control group(routine culture),1,25-(OH)2D3 group[100 nmol/L 1,25-(OH)2D3],IL-6 group(20 ng/mL IL-6),and 1,25-(OH)2D3+IL-6 group[100 nmol/L 1,25-(OH)2D3+20 ng/mL IL-6].Membrane expression of CD23 and IgE secretion were analyzed in each group.Results:Serum 25-(OH)D level in the allergy group was significantly lower than that in the control group(P＜0.001)and showed a weak negative correlation with sCD23 levels(r=-0.248).ROC curve analysis indicated that serum 25-(OH)D had moderate diagnostic value for house dust mite allergy in children(AUC=0.769).In vitro experiments demonstrated that compared with the negative control group,CD23 membrane expression,p-STAT3 expression and IgE secretion were significantly reduced in the 1,25-(OH)2D3 groups in a concentration-dependent manner(all P＜0.01).Time-course experiments revealed that 100 nmol/L 1,25-(OH)2D3 significantly inhibited p-STAT3 expression within 30 minutes and markedly reduced IgE secretion after 48 hours(P＜0.01).Compared with the 1,25-(OH)2D3 group,the 1,25-(OH)2D3+IL-6 group showed significantly increased CD23 membrane expression and IgE secretion(P＜0.05).Conclusion:Vitamin D may downregulate CD23 expression by inhibiting STAT3 phosphorylation,thereby reducing IgE production from B cells in house dust mite allergy.