The Significance Of Neutrophil Extracellular Traps And B Lymphocytes In Renal Tissue Of Patients With Lupus Nephritis And Anca Associated Small Vasculitis

Objective:To investigate the expression of Neutrophil Extracellular traps(NETs) and B lymphocytes in renal tissue of patients with lupus nephritis(LN)and ANCA associated small vasculitis(AASV)and to investigate their pathogenic mechanism.Methods:Immunohistochemistry was used to detect the expression of NETs (citrullinated histone H3as the marker)and the infiltration of B lymphocytes (CD19as the marker) in renal specimen of the four groups(Lupus Nephritis group, n=20ANCA associated small vasculitis(AASV) group, n=8; minimal change disease (MCD)group, n=8; normal control group, n=3).Analyze the chronic and the activity index in renal tissues of LN and AASV and to analyze their relationship with NETs and B lymphocytes.Results:①The expression of NETs:The expression of NETs was absent in the renal tissues of the normal control group and the MCD group. However, they increased markedly in LN, especially in areas such as glomeruli with moderate and severe mesangial cells proliferation, cellular crescents, and tubulointerstitial areas with inflammatory cell infiltration. In LN,compared with other types of glomeruli, the expression of NETs was significantly increased in glomeruli with moderate and severe mesangial cell proliferation(P=0.01). The expression of NETs was widely expressed in AASV,but NETs was absent in the renal tissues of the normal control group and the MCD group. In AASV, NETs was mainly distributed in areas such as interstitial tissue with inflammatory cell infiltration and tubular, and in glomeruli with moderate and severe mesangial cells proliferation.②The expression of B lymphocytes:The expression of B lymphocytes was absent in the renal tissues of the normal control group and the MCD group. However, they increased markedly in LN, especially in peri-glomerular areas with glomerulosclerosis,moderate and severe mesangial cells proliferation, and in tubulointerstitial areas with inflammatory cell infiltration. The expression of B lymphocytes was absent in glomeruli. In AASV, the expression of B lymphocytes was similar in LN.③In LN, in the glomeruli with moderate and severe glomerular mesangial cell proliferation, the mean number of positive stained cells with NETs (1.418±1.366) was positively correlated with renal pathological active index (r=0.620,p=0.004),the score of SLE-DAI (SLE-disease activity index, SLE-DAI)(r=0.492,p=0.027) and the mean number of positive stained cells of NETs in tubular cells (7.05±7.47)(r=0.558,p=0.011). In renal interstitial tissue, the positive stained cells of NETs(0.465±0.451/HPF) were correlated with CD19positive stained cells of B lymphocytes (6.07±7.70/HPF)(r=0.573,p=0.008) and renal pathological chronic index(r=0.645, p=0.002).In AASV, with the relative small sample number,NETs was not showed significant correlation with the score of BVAS, eGFR, renal pathological active index, B lymphocytes.