Study On The Activation Of Neutrophils By IgA1 Immune Complex In Children With Henoch Schonlein Purpura

Objective: To research the relationship between IgA1 immune complex(IgA1-IC)and the activation of neutrophils(Neu),To explore its role in the pathogenesis of HSP.Method: Selectioned the first diagnosis of Henoch-Schonlein Purpura(HSP)in children from August 2016 to August 2017 in Department of Pediatrics,The First hospital of Lanzhou University,who ware not received glucocorticoid and immunosuppressive therapy in past four weeks,and exclusion of rheumatoid immune system disease,allergic disease,or other kidney disease,and exclusive with bacterial infection of children with HSP as the research object,eventually 108 cases of children were enrolled in the study,including 32 cases diagnosed during hospitalization or follow-up Henoch-Schonlein Purpura nephritis(HSPN),8 underwent renal biopsy.At the same time,92 children with non-infectious factors were collected as the control group,and without renal organic diseases.Both groups were collected blood samples,determination of IgA1-IC,neutrophils myeloperoxidase(MPO)and elastase(NE)levels,flow cytometry detection the percentage of neutrophils CD89+,Real-time PCR detection the expression of CD89 mRNA.Follow-up period of 6 months after discharge,understanding the disease recovery and the incidence of HPSN.Results:(1)In comparison with the control group,the content of IgA1-IC was significantly higher(P < 0.05);and there was no significant difference in the level of HSPN compared with NHSPN group(P > 0.05).(2)Compared with the control group,the percentage of neutrophil CD89+ increased significantly in HSP group(P < 0.05).The percentage of CD89+ in HSPN group was significantly higher than that in NHSPN group(P < 0.05).The expression of CD89 mRNA in the HSP group was significantly higher than that in the control group(P < 0.05).There was no significant difference between the expression of CD89 mRNA in the HSPN group and NHSPN group(P > 0.05).(3)The change of neutrophil MPO and NE were significantly higher in HSP compared with the control group(P < 0.05),and compared with HSPN group,this difference was not significant(P > 0.05).(4)Person correlation analysis results show that IgA1-IC is positively correlated with NE level.Conclusion: The level of IgA-IC in children with HSP was significantly increased,through the combination of IgA Fc receptor(CD89)on the surface of neutrophils(Neu)and excessive activation of Neu,play an important role in the pathogenesis of HSP.