The Characteristics And Outcome Prediction Of Anti-Neutrophil Cytoplasmic Antibody Associated Vasculitis With Renal Involvement

Objective:High-dose methylprednisolone pulses were one of the main treatments for anti-neutrophil cytoplasmic autoantibody(ANCA)associated vasculitides(AAV)but had obvious side effects.We aimed to know the efficacy and who would have good responses to this treatment in Chinese AAV patients with severe renal involvement.In addition,we analysed the clinical characteristics and pathogenesis of AAV patients with elevated IgG4 levels.Methods:1.One hundred and eleven AAV patients with an estimated glomerular filtration rate(eGFR)of 10ml/min or less at admission were included.The MP group(n=57)received intravenous methylprednisolone 500 mg/d for 3 days,while the control group(n=54)had not.The outcomes and adverse events between two groups were compared.Besides,predictors for dialysis independence and good response of intravenous methylprednisolone were analyzed using Cox regression analysis and ROC curves respectively.2.We compared the characteristics of AAV patients,IgG4-RD patients and concomitant AAV and IgG4-RD patients in our center.One hundred and sixty-nine AAV patients,58 IgG4-related disease patients and 8 concomitant patients were included.Besides,The serum IgG subclasses of MPO-ANCA were measured.Results:1.Their median duration of follow-up was 31(range,3 to 134)months.Eleven patients(19.3%)in MP group and 20 patients(37.0%)in control group were died(P=0.056).Twenty-one patients(36.8%)in MP group and 29 patients(53.7%)in control group were on maintaining dialysis(P=0.088).Twenty-one patients(36.8%)in MP group remained dialysis independent,more than those(4 patients,7.4%)in control group(P<0.01).Urine protein creatinine ratio(hazard ratio 1.730,95%confidence interval 1.029 to 2.909;P=0.039)was the independent risk factor for dialysis independence.While,the treatment of intravenous methylprednisolone pulses(hazard ratio 0.362,95%confidence interval 0.190 to 0.690;P=0.002)was the independent protective factor for dialysis independence.Those patients with serum creatinine?855?mol/L and urine protein>3.7g/24h at admission may have worse responses to intravenous methylprednisolone pulses(sensibility 56.7%,specificity 85.0%,PPV 100.0%and NPV57.1%).2.The patients in concomitant group had lower levels of hemoglobin,serum albumin,glomerular filtration rate and higher levels of platelet,serum creatinine,erythrocyte sedimentation rate and C-reactive protein compared with IgG4-RD group.Their involved organs were mainly kidney(100%),lung(62.5%)and lacrimal glands(62.5%).They had higher serum globulin level and even lower serum albumin level than AAV patients.The IgG4 subclass of MPO-ANCA was higher in concomitant group than that in AAV group(OD450 value 12.42±6.63 vs 3.03±3.67,P=0.017),whereas the other three subclasses(IgG1,IgG2 and IgG3)of MPO-ANCA were parallel between these groups.Conclusions:Intravenous methylprednisolone pulses could improve the long-term outcome in term of dialysis independence and tend to decrease mortality for Chinese AAV patients with severe renal involvement.Those patients with serum creatinine?855?mol/L and urine protein ?3.7g/24h at admission may have worse responses to intravenous methylprednisolone pulses.We also showed a new overlap syndrome of AAV and IgG4-RD,and the IgG4 subclass of ANCA may be a pathogenic factor in this concomitant disease.