| Background and Objective Henoch-Schonlein’s purpura(HSP)is one of the most common systemic small vasculitis in children, termed as Henoch-Schonlein’s purpura nephritis(HSPN) when a person with renal injury was found. The etiology and pathophysiology of HSP are not completely clarified. Many studies have revealed that complement activation may involve in the inflammatory injury in HSP and HSPN. C3 is the highest concentrations in serum complement components, C4 is an important components in classic pathway activetion. Ig A-contained immune complexes deposition can be found not only in the kidney, but also in other organs, such as the skin. Complement receptor one(CR1,also termed as CD35), is positively associated with various autoimmune diseases. CD35 is an important complement receptor molecule. C4 binding protein(C4bp) is an important complement regulatory protein. We presume that CD35 and C4 bp may take a part in the injury process in children with HSP and HSPN. The goal of the present study was to detect the expressions of CD35 and C4 bp in the serum and kidney tissue, and further investigate the role of erythrocyte immune function and serological complement in HSPN. Methods The study sample was composed of a consecutive series of children admitted to the Department of Pediatrics, the First Affiliated Hospital of Zhengzhou University between December 2012 and October 2014, with minimum follow up of 6 months. According to whether a child with renal injury, 70 children with HSP were divided into HSP group(n = 30) and HSPN group(n = 40). Simultaneously, 20 age-matched healthy children were collected as the healthy control group(n=20), and normal renal tissue sections from 5 cases due to renal trauma were selected as the control group(n=5). The quantitative expressions of erythrocyte CD35 were assessed by Flow Cytometer; while using rate nephelometry serum C3 and C4 levels were measured; Serum levels of C4 bp and circulating immune complexes(CIC) were measured respectively using enzyme linked immunosorbent assay(ELISA); All of children with HSPN received renal biopsy, followed by routine diagnosis pathologically and quantitative analysis of renal tissue; The expression of CD35 and C4 bp in renal tissues were detected by immunohistochemistry. Results 1. The levels of serum C3 and C4 had no difference in three groups(all P >0.05).The levels of erythrocyte CD35 in children with HSPN group and HSP group were significantly lower than the healthy control group, the difference was statistically significant(F=10.510, P<0.05), and there was no significant difference between the HSPN group and HSP group; The HSPN group and HSP group had significant higher levels of serum C4 bp and CIC compared with the healthy control group, the difference was statistically significant(x2=9.582, P<0.05; x2=6.545, P<0.001), and there was significant difference between the HSPN group and HSP group(Z=-2.007, P <0.05; Z=-2.053,P <0.05). 2. The expression of CD35 was detected in glomerular epithelial cells, not renal tubule and renal interstitial; as for HSPN, the deposition of CD35 in renal tissue decreased than the kidney control group, decreasing with the aggravation pathology hierarchically(F=14.626, P<0.05). 3. Only a light expression of C4 bp was found in normal renal tissue; as for HSPN, the deposition of C4 bp in renal tissue increased than kidney control group, increasing with the aggravation pathology hierarchically(F=18.907, P<0.05). 4. As for HSPN children, there was a significant positive correlation between the levels of the erythrocyte CD35 and the deposition of CD35 in renal tissue(r=0.489, P<0.05). Significant negative correlation between the levels of the erythrocyte CD35 and the extent of histological changes(r=-0.615, P<0.01); There was a significant negative correlation between the deposition of CD35 in renal tissue and the extent of histological changes(r=-0.386, P<0.05). 5. As for HSPN children, although there was no significant correlation between the serum levels of C4 bp and the deposition of C4 bp in renal tissue(P>0.05); And no significant correlation was found between the serum levels of C4 bp and the extent of histological changes(P>0.05); There was a significant positive correlation between the deposition of C4 bp in renal tissue and the extent of histological changes(r=0.528, P<0.05). Conclusion 1. CD35 may play an essential role in renal lesion suggested by a decreased expression of it, which can promote the progress of HSPN in children. 2. C4 bp may play an essential role in renal lesion suggested by an increased expression of it, which can promote the progress of HSPN in children. 3. The monitoring levels of erythrocyte membrance CD35 could indirectly the expression of CD35 in renal tissue reaction conditions and the degree of in kidney damage. |
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