Study Of Changes In Serum B Cell Activating Factor,Immunoglobulin And Peripheral Blood B Lymphocyte Subsets In Children With IgA Vasculitis

Objective:To observe the changes of the level of serum B cell activating factor(BAFF),immunoglobulin,and counts of peripheral blood B lymphocyte subunits in children with IgA vasculitis(IgAV),to investigate their roles in the pathogenesis of IgAV in children,and to provide new ideas for the clinical diagnosis and individualized treatment of IgAV.Methods:Totally 33 newly diagnosed IgAV patients were enrolled in the research as the observation group,who were hospitalized in the Department of Nephrology and Rheumatology,Affiliated Hospital of Qingdao University from January,2022 to December,2022.40 healthy children who underwent physical examination in our hospital were selected as the control group in the same period.Clinical data was collected,the serum levels of BAFF were analyzed with enzyme-linked immunosorbent assay(ELISA),the serum immunoglobulins levels were detected with immune scattering turbidimetry,and the counts of peripheral blood B lymphocytes subunits were detected with flow cytometry.The statistical software SPSS22.0 was used for data analysis.Results:1.The changes in serum BAFF levels were significantly higher in the IgAV group(1145.79±377.53pg/ml)than that in the normal control group(386.32±56.07pg/ml),with a statistically significant difference(t=11.453,p<0.010).2.Changes in serum immunoglobulin levels.The serum IgA expression level[2.020(1.6,2.4)]in the IgAV group was significantly higher than that in the control group[1.060(0.7,1.7)],and the difference was statistically significant(p<0.01);The serum IgE expression level[110.00(33.1435.5)]was higher than that of the control group[47.065(19.3,98.2)](p<0.01);There was no significant difference in the expression levels of serum IgG and IgM compared to the control group(all p>0.05).3.Compared with the normal control group,the fine grouping changes of peripheral blood B lymphocytes in IgAV children showed a significant decrease in peripheral blood marginal zone(MZ)B lymphocyte count(p<0.05),plasma cell count(p<0.05),and immature B lymphocyte count(p<0.01).However,there was no significant difference in B lymphocyte count,initial B lymphocyte count,and classical transformation B lymphocyte count(all p>0.05).4.Correlation analysis between serum BAFF levels and immunoglobulin expression levels in children with IgAV.Serum BAFF showed a moderate positive correlation with IgA(R~2=0.263,p=0.001),while serum BAFF levels were not significantly correlated with IgG,IgM,and IgE(all p>0.05).5.Correlation analysis between serum BAFF and peripheral blood B lymphocyte subsets in children with IgAV group.There was no significant correlation between serum BAFF and peripheral blood B lymphocyte subsets(all p>0.05).Conclusions:1.The serum BAFF levels in children with IgAV are elevated and positively correlated with IgA levels,indicating that the excessive activation of B cells caused by BAFF is involved in the immune pathogenesis of IgAV.2.The serum IgE expression level in children with IgAV also significantly increased,and the reason and role of IgAV are unknown.3.The levels of peripheral B cells and immature B cells closely related to immune regulation in children with IgAV have significantly decreased,indicating a disruption in the immune regulation mechanism of B cells.