The significances of peripheral neutrophils CD55 and myeloperoxidase expression in patients with myeloperoxidase-specific anti-neutrophil cytoplasmic antibody associated vasculitis / 中华内科杂志

ABSTRACT

Objective To investigate the expression of CD55 and myeloperoxidase (MPO) on neutrophils in patients with MPO-specific anti-neutrophil cytoplasmic antibody associated vasculitis(MPO-AAV), and analyze the relationship between the expression and clinical manifestation.Methods Forty untreated patients with active MPO-AAV (patient group) and 30 healthy volunteers (control group) were enrolled in this study.The CD55 on neutrophils and both membrane and cytoplasmic MPO were detected by flow cytometry.Serum fragment-from the activated complement factor B(Ba) and MPO were measured by ELISA.The clinical activity of vasculitis was valued by Birmingham vasculitis activity score-version 3(BVAS-V3).The significance of laboratory data was evaluated by Spearman correlation test and multivariate linear regression analysis.Results (1)The mean fluorescence intensity(MFI) of CD55 expressed on neutrophils was significantly higher than that in control group[4 068.6±2 306.0 vs 2 999.5±1 504.9,P=0.033].Similar results of serum MPO and Ba in patient group were found compared to controls [500.0(381.0, 612.7) IU/L vs 286.9(225.5, 329.1) IU/L,P<0.001;35.2(25.2, 79.5) ng/L vs 18.0(15.0, 28.0) ng/L,P<0.001], respectively.However, MIF of cytoplasmic MPO in patients was significantly lower than that of control group(1 577.1±1 175.9 vs 3 105.3±2 323.0,P=0.003).(2) In patient group, cytoplasmic intensity of MPO was negatively associated with the serum levels of MPO(r=-0.710,P<0.001) and Ba (r=-0.589,P=0.001).Moreover, serum MPO was positively associated with serum Ba(r=0.691,P<0.001).Membrane intensity of CD55 on neutrophils was positively correlated with patient age (r=0.514, P=0.001), C reactive protein (r=0.376, P=0.018), peripheral neutrophils count (r=0.485, P=0.001) and BVAS-V3 (r=0.484, P=0.002), whereas negative correlation between membrane CD55 and disease duration was seen (r=-0.403,P=0.01).(3) The result of multiple linear regression analysis showed there was statistically significant positive correlation between MFI of CD55 expressed on neutrophils and BVAS-V3 (β=0.001,P=0.027).Conclusions In MPO-AAV,CD55 expression on neutrophils is markedly enhanced, which is one of the independent risk factors related to disease activity.It might protect neutrophils from attacking AAV, CD55 expression on neutrophils is markedly enhanced, which is one of the independent risk factors related to disease activity.It might protect neutrophils from attacking by complement alternative pathway.Activated neutrophils release more MPO and lysosome to intensify the inflammation reaction and aggravate the disease.Thus CD55 might become a new potential target for the treatment of this disease in the future.